From f2b18f26228f559e9bddaaf340a7890da616327f Mon Sep 17 00:00:00 2001
From: Ralf Gommers <ralf.gommers@gmail.com>
Date: Thu, 28 Dec 2023 21:05:14 +0100
Subject: [PATCH 01/22] CI: add CI jobs for different BLAS configs

Adapted largely from NumPy's `linux_blas.yml`
---
 .github/workflows/linux_blas.yml | 123 +++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 .github/workflows/linux_blas.yml

diff --git a/.github/workflows/linux_blas.yml b/.github/workflows/linux_blas.yml
new file mode 100644
index 000000000000..665ee2964601
--- /dev/null
+++ b/.github/workflows/linux_blas.yml
@@ -0,0 +1,123 @@
+name: BLAS tests (Linux)
+
+# This file is meant for testing different BLAS/LAPACK flavors and build
+# options on Linux. All other yml files for Linux will only test without BLAS
+# (mostly because that's easier and faster to build) or with the same 64-bit
+# OpenBLAS build that is used in the wheel jobs.
+#
+# Jobs and their purpose:
+#
+#   - openblas32_stable_nightly:
+#         Uses the 32-bit OpenBLAS builds, both the latest stable release
+#         and a nightly build.
+#   - openblas_no_pkgconfig_fedora:
+#         Test OpenBLAS on Fedora. Fedora doesn't ship .pc files for OpenBLAS,
+#         hence this exercises the "system dependency" detection method.
+#   - flexiblas_fedora:
+#         Tests FlexiBLAS (the default on Fedora for its own packages), via
+#         pkg-config. FlexiBLAS allows runtime switching of BLAS/LAPACK
+#         libraries, which is a useful capability (not tested in this job).
+#   - openblas_cmake:
+#         Tests whether OpenBLAS LP64 is detected correctly when only CMake
+#         and not pkg-config is installed.
+#   - netlib-debian:
+#         Installs libblas/liblapack, which in Debian contains libcblas within
+#         libblas.
+#   - netlib-split:
+#         Installs vanilla Netlib blas/lapack with separate libcblas, which is
+#         the last option tried in auto-detection.
+#   - mkl:
+#         Tests MKL installed from PyPI (because easiest/fastest, if broken) in
+#         3 ways: both LP64 and ILP64 via pkg-config, and then using the
+#         Single Dynamic Library (SDL, or `libmkl_rt`).
+#   - blis:
+#         Simple test for LP64 via pkg-config
+#   - atlas:
+#         Simple test for LP64 via pkg-config
+
+on:
+  pull_request:
+    branches:
+      - main
+      - maintenance/**
+
+defaults:
+  run:
+    shell: bash
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read # to fetch code (actions/checkout)
+
+jobs:
+  # openblas32_stable_nightly:
+  # openblas_no_pkgconfig_fedora:
+  # flexiblas_fedora:
+  # openblas_cmake:
+  # mkl:
+  # blis:
+  # atlas:
+
+  netlib-debian:
+    #if: "github.repository == 'rgommers/scipy'"
+    if: false   # no cblas.pc, need to switch to Meson auto
+    runs-on: ubuntu-latest
+    name: "Debian libblas/liblapack"
+    steps:
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      with:
+        submodules: recursive
+        fetch-depth: 0
+    - uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c # v5.0.0
+      with:
+        python-version: '3.11'
+
+    - name: Install dependencies
+      run: |
+        pip install -r requirements/all.txt
+        pip install git+https://github.com/rgommers/meson.git@dependency-openblas
+        sudo apt-get install liblapack-dev pkg-config
+
+    - name: Build
+      run: |
+        python dev.py build -C-Dblas=blas -C-Dlapack=lapack
+
+    - name: Test
+      run: |
+        python dev.py test -j2
+
+
+  netlib-split:
+    if: "github.repository == 'scipy/scipy'"
+    runs-on: ubuntu-latest
+    container: opensuse/tumbleweed
+    name: "OpenSUSE Netlib BLAS/LAPACK"
+    steps:
+    - name: Install system dependencies
+      run: |
+        # No blas.pc on OpenSUSE as of Nov 2023, so no need to install pkg-config.
+        # If it is needed in the future, use install name `pkgconf-pkg-config`
+        zypper install -y git gcc-c++ gcc-fortran python3-pip python3-devel blas cblas lapack
+
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      with:
+        submodules: recursive
+        fetch-depth: 0
+
+    - name: Install PyPI dependencies
+      run: |
+        pip install --break-system-packages -r requirements/build.txt
+        pip install --break-system-packages git+https://github.com/rgommers/meson.git@dependency-openblas
+
+    - name: Build
+      run: |
+        pip install . --break-system-packages --no-build-isolation -v -Csetup-args=-Dblas=blas -Csetup-args=-Dlapack=lapack
+
+    - name: Test
+      run: |
+        pip install --break-system-packages -r requirements/test.txt
+        cd tools
+        pytest --pyargs scipy -j2

From 30b473a17cb900e40f20cae934de72b630813408 Mon Sep 17 00:00:00 2001
From: Ralf Gommers <ralf.gommers@gmail.com>
Date: Thu, 28 Dec 2023 21:06:19 +0100
Subject: [PATCH 02/22] DEBUG: run BLAS jobs on fork

---
 .github/workflows/linux_blas.yml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/linux_blas.yml b/.github/workflows/linux_blas.yml
index 665ee2964601..24f55e309196 100644
--- a/.github/workflows/linux_blas.yml
+++ b/.github/workflows/linux_blas.yml
@@ -40,6 +40,9 @@ on:
     branches:
       - main
       - maintenance/**
+  push:
+    branches:
+      - ci-blas
 
 defaults:
   run:
@@ -91,7 +94,7 @@ jobs:
 
 
   netlib-split:
-    if: "github.repository == 'scipy/scipy'"
+    if: "github.repository == 'rgommers/scipy'"
     runs-on: ubuntu-latest
     container: opensuse/tumbleweed
     name: "OpenSUSE Netlib BLAS/LAPACK"

From cd447e37205ab9e133fc300a109b849852ed293c Mon Sep 17 00:00:00 2001
From: Ralf Gommers <ralf.gommers@gmail.com>
Date: Sun, 23 Feb 2025 15:36:10 +0100
Subject: [PATCH 03/22] ENH: use Meson's BLAS and LAPACK support

---
 meson.build       |   2 -
 meson.options     |  18 +++--
 scipy/meson.build | 176 +++++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 179 insertions(+), 17 deletions(-)

diff --git a/meson.build b/meson.build
index 371d983a59d1..cdbcc0a5f9ed 100644
--- a/meson.build
+++ b/meson.build
@@ -9,8 +9,6 @@ project(
     'b_ndebug=if-release',
     'c_std=c17',
     'cpp_std=c++17',
-    'blas=openblas',
-    'lapack=openblas'
   ],
 )
 
diff --git a/meson.options b/meson.options
index 3257cb8a8ff5..096d0aa0f6d8 100644
--- a/meson.options
+++ b/meson.options
@@ -1,7 +1,17 @@
-option('blas', type: 'string', value: 'openblas',
-        description: 'option for BLAS library switching')
-option('lapack', type: 'string', value: 'openblas',
-        description: 'option for LAPACK library switching')
+option('blas', type: 'string', value: 'auto',
+        description: 'Option for BLAS library selection. By default, try to find any in the order given by `blas-order`')
+option('lapack', type: 'string', value: 'auto',
+        description: 'Option for LAPACK library selection. By default, try to find any in the order given by `lapack-order`')
+option('blas-order', type: 'array', value: ['auto'],
+       description: 'Order of BLAS libraries to search for. E.g.: mkl,openblas,blis,blas')
+option('lapack-order', type: 'array', value: ['auto'],
+       description: 'Order of LAPACK libraries to search for. E.g.: mkl,openblas,lapack')
+option('use-ilp64', type: 'boolean', value: false,
+       description: 'Use ILP64 (64-bit integer) BLAS and LAPACK interfaces')
+option('blas-symbol-suffix', type: 'string', value: 'auto',
+        description: 'BLAS and LAPACK symbol suffix to use, if any')
+option('mkl-threading', type: 'string', value: 'auto',
+        description: 'MKL threading method, one of: `seq`, `iomp`, `gomp`, `tbb`')
 option('use-g77-abi', type: 'boolean', value: false,
         description: 'If set to true, forces using g77 compatibility wrappers ' +
                      'for LAPACK functions. The default is to use gfortran ' +
diff --git a/scipy/meson.build b/scipy/meson.build
index b3803a4f4592..c34bef307cfb 100644
--- a/scipy/meson.build
+++ b/scipy/meson.build
@@ -85,18 +85,16 @@ else
   _incdir_numpy_abs = incdir_numpy
 endif
 inc_np = include_directories(incdir_numpy)
-# Don't use the deprecated NumPy C API. Define this to a fixed version instead of
-# NPY_API_VERSION in order not to break compilation for released SciPy versions
-# when NumPy introduces a new deprecation.
-numpy_nodepr_api = ['-DNPY_NO_DEPRECATED_API=NPY_1_9_API_VERSION']
-np_dep = declare_dependency(include_directories: inc_np, compile_args: numpy_nodepr_api)
+np_dep = declare_dependency(include_directories: inc_np)
 
 incdir_f2py = incdir_numpy / '..' / '..' / 'f2py' / 'src'
 inc_f2py = include_directories(incdir_f2py)
 fortranobject_c = incdir_f2py / 'fortranobject.c'
 
 npymath_path = _incdir_numpy_abs / '..' / 'lib'
+npyrandom_path = _incdir_numpy_abs / '..' / '..' / 'random' / 'lib'
 npymath_lib = cc.find_library('npymath', dirs: npymath_path)
+npyrandom_lib = cc.find_library('npyrandom', dirs: npyrandom_path)
 
 pybind11_dep = dependency('pybind11', version: '>=2.13.2')
 
@@ -223,6 +221,158 @@ f2py_gen = generator(generate_f2pymod,
 )
 
 
+blas_name = get_option('blas')
+lapack_name = get_option('lapack')
+# This is currently injected directly into CFLAGS/CXXFLAGS for wheel builds
+# (see cibuildwheel settings in pyproject.toml), but used by CI jobs already
+blas_symbol_suffix = get_option('blas-symbol-suffix')
+
+use_ilp64 = get_option('use-ilp64')
+if use_ilp64
+  blas_interface = ['interface: ilp64']
+else
+  blas_interface = ['interface: lp64']
+endif
+
+blas_order = get_option('blas-order')
+if blas_order == ['auto']
+  blas_order = []
+  if host_machine.system() == 'darwin'
+    blas_order += 'accelerate'
+  endif
+  if host_machine.cpu_family() == 'x86_64'
+    blas_order += 'mkl'
+  endif
+  blas_order += ['openblas', 'flexiblas', 'blis', 'blas']
+endif
+lapack_order = get_option('lapack-order')
+if lapack_order == ['auto']
+  lapack_order = []
+  if host_machine.system() == 'darwin'
+    lapack_order += 'accelerate'
+  endif
+  if host_machine.cpu_family() == 'x86_64'
+    lapack_order += 'mkl'
+  endif
+  lapack_order += ['openblas', 'flexiblas', 'lapack']
+endif
+
+# MKL-specific options
+_threading_opt = get_option('mkl-threading')
+if _threading_opt == 'auto'
+  # Switch default to iomp once conda-forge missing openmp.pc issue is fixed
+  mkl_opts = ['threading: seq']
+else
+  mkl_opts = ['threading: ' + _threading_opt]
+endif
+blas_opts = {'mkl': mkl_opts}
+mkl_version_req = '>=2023.0'  # see gh-24824
+mkl_may_use_sdl = not use_ilp64 and _threading_opt in ['auto', 'iomp']
+
+
+# BLAS detection.
+#
+# First try scipy-openblas, and if found don't look for cblas or lapack, we
+# know what's inside the scipy-openblas wheels already.
+if blas_name == 'openblas' or blas_name == 'auto'
+  blas = dependency('scipy-openblas', method: 'pkg-config', required: false)
+  if blas.found()
+    blas_name = 'scipy-openblas'
+  endif
+endif
+if blas_name == 'auto'
+  foreach _name : blas_order
+    if _name == 'mkl'
+      blas = dependency('mkl',
+        modules: ['cblas'] + blas_interface + mkl_opts,
+        required: false,  # may be required, but we need to emit a custom error message
+        version: mkl_version_req,
+      )
+      # Insert a second try with MKL, because we may be rejecting older versions
+      # or missing it because no pkg-config installed. If so, we need to retry
+      # with MKL SDL, and drop the version constraint (this always worked).
+      if not blas.found() and mkl_may_use_sdl
+        blas = dependency('mkl', modules: ['cblas', 'sdl: true'], required: false)
+      endif
+    else
+      if _name == 'flexiblas' and use_ilp64
+        _name = 'flexiblas64'
+      endif
+      blas = dependency(_name, modules: ['cblas'] + blas_interface, required: false)
+    endif
+    if blas.found()
+      break
+    endif
+  endforeach
+else
+  if blas_name == 'mkl'
+    blas = dependency('mkl',
+      modules: ['cblas'] + blas_interface + mkl_opts,
+      required: false,
+      version: mkl_version_req,
+    )
+    # Same deal as above - try again for MKL
+    if not blas.found() and mkl_may_use_sdl
+      blas = dependency('mkl', modules: ['cblas', 'sdl: true'], required: false)
+    endif
+  else
+    blas = dependency(blas_name, modules: ['cblas'] + blas_interface, required: false)
+  endif
+endif
+
+if not blas.found()
+  error('No BLAS library detected! SciPy needs one, please install it.')
+endif
+
+_args_blas = []  # note: used for C and C++ via `blas_dep` below
+if use_ilp64
+  _args_blas += ['-DHAVE_BLAS_ILP64']
+  if 'openblas' in blas.name()
+    _args_blas += ['-DOPENBLAS_ILP64_NAMING_SCHEME']
+  endif
+endif
+if blas_symbol_suffix == 'auto'
+  if blas_name == 'scipy-openblas' and use_ilp64
+    blas_symbol_suffix = '64_'
+  else
+    blas_symbol_suffix = blas.get_variable('symbol_suffix', default_value: '')
+  endif
+  message(f'BLAS symbol suffix: @blas_symbol_suffix@')
+endif
+if blas_symbol_suffix != ''
+  _args_blas += ['-DBLAS_SYMBOL_SUFFIX=' + blas_symbol_suffix]
+endif
+blas_dep = declare_dependency(
+  dependencies: [blas],
+  compile_args: _args_blas,
+)
+
+# LAPACK detection
+if 'mkl' in blas.name() or blas.name() == 'accelerate' or blas_name == 'scipy-openblas'
+  # For these libraries we know that they contain LAPACK, and it's desirable to
+  # use that - no need to run the full detection twice.
+  lapack = blas
+else
+  if lapack_name == 'auto'
+    foreach _name : lapack_order
+      lapack = dependency(_name, modules: ['lapack'] + blas_interface, required: false)
+      if lapack.found()
+        break
+      endif
+    endforeach
+  else
+    lapack = dependency(lapack_name, modules: ['lapack'] + blas_interface, required: false)
+  endif
+endif
+
+if not lapack.found()
+  error('No LAPACK library detected! SciPy needs one, please install it.')
+endif
+lapack_dep = declare_dependency(dependencies: [lapack, blas_dep])
+
+
+
+###############################################
 # TODO: 64-bit BLAS and LAPACK
 #
 # Note that this works as long as BLAS and LAPACK are detected properly via
@@ -310,10 +460,11 @@ dependency_map = {
   'PYBIND11': pybind11_dep,
 }
 
-# FIXME: conda-forge sets MKL_INTERFACE_LAYER=LP64,GNU, see gh-11812.
-#        This needs work on gh-16200 to make MKL robust. We should be
-#        requesting `mkl-dynamic-lp64-seq` here. And then there's work needed
-#        in general to enable the ILP64 interface (also for OpenBLAS).
+# Reuse the names, so we ensure we don't lose the arguments wrapped in with
+# declare_dependency. Also, avoids changing `dependencies: blas` to blas_dep in other files.
+blas = blas_dep
+lapack = lapack_dep
+
 uses_mkl = blas.name().to_lower().startswith('mkl') or lapack.name().to_lower().startswith('mkl')
 uses_accelerate = blas.name().to_lower().startswith('accelerate') or lapack.name().to_lower().startswith('accelerate')
 use_g77_abi = uses_mkl or uses_accelerate or get_option('use-g77-abi')
@@ -321,14 +472,14 @@ if use_g77_abi
   g77_abi_wrappers = static_library(
     'g77_abi_wrappers',
     ['_build_utils/src/wrap_g77_abi.c'],
-    dependencies: [py3_dep, cblas, blas_dep, np_dep],
+    dependencies: [py3_dep, blas, np_dep],
     gnu_symbol_visibility: 'hidden',
   )
 else
   g77_abi_wrappers = static_library(
     'dummy_g77_abi_wrappers',
     ['_build_utils/src/wrap_dummy_g77_abi.c'],
-    dependencies: [py3_dep, blas_dep, np_dep],
+    dependencies: [py3_dep, blas, np_dep],
     gnu_symbol_visibility: 'hidden',
   )
 endif
@@ -360,6 +511,9 @@ python_sources = [
   '__init__.py',
   '_distributor_init.py',
   'conftest.py',
+  'linalg.pxd',
+  'optimize.pxd',
+  'special.pxd',
 ]
 
 if fs.exists('_distributor_init_local.py')

From bd8bc0c5fde2b5c416edeecafdd339ce216a95a9 Mon Sep 17 00:00:00 2001
From: Ralf Gommers <ralf.gommers@gmail.com>
Date: Thu, 28 Dec 2023 22:28:15 +0100
Subject: [PATCH 04/22] Squash several commits to simplify rebasing

ci fix

Avoid pytest-cov, and install python311 on OpenSUSE

CI: enable Debian libblas/liblapack job

CI: add Fedora jobs for OpenBLAS and FlexiBLAS

OpenBLAS is detected without pkg-config, because Fedora does not
ship an openblas.pc file. FlexiBLAS is detected through pkg-config.

CI: add job using BLIS

CI: add MKL job

CI: add Accelerate (NEWLAPACK LP64) job

ENH: enable new macOS Accelerate BLAS/LAPACK support

BUG: fix issue with picking up use-g77-abi flag
---
 .github/workflows/linux_blas.yml   | 186 ++++++++++++++++++++++++++---
 .github/workflows/macos.yml        |  30 +++++
 ci/_blis_debian.pc                 |   8 ++
 scipy/_build_utils/src/npy_cblas.h |  15 +++
 scipy/meson.build                  |  13 +-
 5 files changed, 232 insertions(+), 20 deletions(-)
 create mode 100644 ci/_blis_debian.pc

diff --git a/.github/workflows/linux_blas.yml b/.github/workflows/linux_blas.yml
index 24f55e309196..db2480c67bbd 100644
--- a/.github/workflows/linux_blas.yml
+++ b/.github/workflows/linux_blas.yml
@@ -56,17 +56,80 @@ permissions:
   contents: read # to fetch code (actions/checkout)
 
 jobs:
-  # openblas32_stable_nightly:
-  # openblas_no_pkgconfig_fedora:
-  # flexiblas_fedora:
-  # openblas_cmake:
-  # mkl:
-  # blis:
-  # atlas:
+  # openblas32_stable_nightly: (see linux_meson.yml for scipy-openblas32 test job)
+  # atlas: (see linux_meson.yml for ATLAS test job)
+  # accelerate: (see macos_meson.yml)
+
+  openblas_no_pkgconfig_fedora:
+    #if: "github.repository == 'rgommers/scipy'"
+    if: false  # WORKS
+    runs-on: ubuntu-latest
+    container: fedora:39
+    name: "OpenBLAS (Fedora, no pkg-config)"  # openblas.pc not shipped by Fedora
+    steps:
+    - name: Install system dependencies
+      run: |
+        dnf install git gcc-gfortran g++ python3-devel openblas-devel -y
+
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      with:
+        submodules: recursive
+        fetch-depth: 0
+
+    - name: Install dependencies from PyPI
+      run: |
+        pip install -r requirements/build.txt
+        pip install build
+        pip install git+https://github.com/numpy/meson.git@main-numpymeson
+
+    - name: Build
+      run: |
+        python3 -m build -wnx -Cbuild-dir=build
+        python3 -m pip install dist/scipy*.whl
+
+    - name: Test
+      run: |
+        pip install -r requirements/test.txt
+        cd tools
+        pytest --pyargs scipy -n2 -m "not slow"
+
+  flexiblas_fedora:
+    #if: "github.repository == 'rgommers/scipy'"
+    if: false  # WORKS
+    runs-on: ubuntu-latest
+    container: fedora:39
+    name: "FlexiBLAS Fedora"  # flexiblas.pc is shipped by Fedora
+    steps:
+    - name: Install system dependencies
+      run: |
+        dnf install git gcc-gfortran g++ python3-devel flexiblas-devel -y
+
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      with:
+        submodules: recursive
+        fetch-depth: 0
+
+    - name: Install dependencies from PyPI
+      run: |
+        pip install -r requirements/build.txt
+        pip install build
+        pip install git+https://github.com/numpy/meson.git@main-numpymeson
+
+    - name: Build
+      run: |
+        python3 -m build -wnx -Cbuild-dir=build
+        python3 -m pip install dist/scipy*.whl
+
+    - name: Test
+      run: |
+        pip install -r requirements/test.txt
+        cd tools
+        pytest --pyargs scipy -n2 -m "not slow"
+
 
   netlib-debian:
     #if: "github.repository == 'rgommers/scipy'"
-    if: false   # no cblas.pc, need to switch to Meson auto
+    if: false  # WORKS
     runs-on: ubuntu-latest
     name: "Debian libblas/liblapack"
     steps:
@@ -81,12 +144,12 @@ jobs:
     - name: Install dependencies
       run: |
         pip install -r requirements/all.txt
-        pip install git+https://github.com/rgommers/meson.git@dependency-openblas
+        pip install git+https://github.com/numpy/meson.git@main-numpymeson
         sudo apt-get install liblapack-dev pkg-config
 
     - name: Build
       run: |
-        python dev.py build -C-Dblas=blas -C-Dlapack=lapack
+        python dev.py build
 
     - name: Test
       run: |
@@ -94,7 +157,8 @@ jobs:
 
 
   netlib-split:
-    if: "github.repository == 'rgommers/scipy'"
+    #if: "github.repository == 'rgommers/scipy'"
+    if: false  # WORKS
     runs-on: ubuntu-latest
     container: opensuse/tumbleweed
     name: "OpenSUSE Netlib BLAS/LAPACK"
@@ -103,7 +167,7 @@ jobs:
       run: |
         # No blas.pc on OpenSUSE as of Nov 2023, so no need to install pkg-config.
         # If it is needed in the future, use install name `pkgconf-pkg-config`
-        zypper install -y git gcc-c++ gcc-fortran python3-pip python3-devel blas cblas lapack
+        zypper install -y git gcc-c++ gcc-fortran python3-pip python311 python3-devel blas cblas lapack
 
     - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
       with:
@@ -113,7 +177,7 @@ jobs:
     - name: Install PyPI dependencies
       run: |
         pip install --break-system-packages -r requirements/build.txt
-        pip install --break-system-packages git+https://github.com/rgommers/meson.git@dependency-openblas
+        pip install --break-system-packages git+https://github.com/numpy/meson.git@main-numpymeson
 
     - name: Build
       run: |
@@ -121,6 +185,98 @@ jobs:
 
     - name: Test
       run: |
-        pip install --break-system-packages -r requirements/test.txt
+        pip install --break-system-packages pytest hypothesis pytest-xdist threadpoolctl pooch
         cd tools
-        pytest --pyargs scipy -j2
+        pytest --pyargs scipy -n2 -m "not slow"
+
+
+  mkl:
+    if: "github.repository == 'rgommers/scipy'"
+    runs-on: ubuntu-latest
+    name: "MKL (LP64 split, SDL)"
+    steps:
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      with:
+        submodules: recursive
+        fetch-depth: 0
+    - uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c # v5.0.0
+      with:
+        python-version: '3.11'
+
+    - name: Install dependencies
+      run: |
+        pip install -r requirements/all.txt
+        pip install git+https://github.com/numpy/meson.git@main-numpymeson
+        pip install "mkl==2023.2.0" "mkl-devel==2023.2.0"
+
+    - name: Repair MKL pkg-config files and symlinks
+      run: |
+        # MKL 2023.2 works when installed from conda-forge (except for `-iomp`
+        # and `-tbb` pkg-config files), Spack, or with the standalone Intel
+        # installer. The standalone installer is the worst option, since it's
+        # large and clumsy to install and requires running a setvars.sh script
+        # before things work. The PyPI MKL packages are broken and need the
+        # fixes in this step. For details, see
+        # https://github.com/conda-forge/intel_repack-feedstock/issues/34
+        cd $Python3_ROOT_DIR/lib/pkgconfig
+        sed -i 's/\/intel64//g' mkl*.pc
+        # add the expected .so -> .so.2 symlinks to fix linking
+        cd ..
+        for i in $( ls libmkl*.so.2 ); do ln -s $i ${i%.*}; done
+
+    - name: Build with defaults (LP64)
+      run: |
+        pkg-config --libs mkl-dynamic-lp64-seq  # check link flags
+        python dev.py build
+
+    - name: Test
+      run: python dev.py test
+
+    - name: Build without pkg-config (default options, SDL)
+      run: |
+        git clean -xdf > /dev/null
+        pushd $Python3_ROOT_DIR/lib/pkgconfig
+        rm mkl*.pc
+        popd
+        export MKLROOT=$Python3_ROOT_DIR
+        python dev.py build
+
+    - name: Test
+      run: python dev.py test
+
+
+  blis:
+    #if: "github.repository == 'rgommers/scipy'"
+    if: false  # WORKS
+    runs-on: ubuntu-latest
+    name: "BLIS"
+    steps:
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      with:
+        submodules: recursive
+        fetch-depth: 0
+    - uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c # v5.0.0
+      with:
+        python-version: '3.11'
+
+    - name: Install dependencies
+      run: |
+        pip install -r requirements/all.txt
+        pip install git+https://github.com/numpy/meson.git@main-numpymeson
+        sudo apt-get install libblis-dev libopenblas-dev pkg-config
+
+    - name: Add BLIS pkg-config file
+      run: |
+        # Needed because blis.pc missing in Debian:
+        # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=989076
+        # The alternative here would be to use another distro or Miniforge
+        sudo cp ci/_blis_debian.pc /usr/lib/x86_64-linux-gnu/pkgconfig/blis.pc
+        # Check if the patch works:
+        pkg-config --libs blis
+        pkg-config --cflags blis
+
+    - name: Build
+      run: python dev.py build -C-Dblas=blis
+
+    - name: Test
+      run: python dev.py test
diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index cc2f83189737..a4b0b5201e49 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -217,3 +217,33 @@ jobs:
 
         pip install pooch pytest hypothesis
         python dev.py -n test
+
+  accelerate:
+    name: Accelerate (LP64)
+    if: "github.repository == 'rgommers/scipy'"
+    runs-on: macos-13
+    steps:
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      with:
+        submodules: recursive
+        fetch-depth: 0
+
+    - uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c # v5.0.0
+      with:
+        python-version: '3.10'
+
+    - uses: maxim-lobanov/setup-xcode@60606e260d2fc5762a71e64e74b2174e8ea3c8bd # v1.6.0
+      with:
+        xcode-version: '14.3'
+
+    - name: Install dependencies
+      run: |
+        pip install -r requirements/all.txt
+        pip install git+https://github.com/numpy/meson.git@main-numpymeson
+        brew install gfortran
+
+    - name: Build against Accelerate (LP64)
+      run: python dev.py build
+
+    - name: Test
+      run: python dev.py test -j2
diff --git a/ci/_blis_debian.pc b/ci/_blis_debian.pc
new file mode 100644
index 000000000000..a4a5c7fbb244
--- /dev/null
+++ b/ci/_blis_debian.pc
@@ -0,0 +1,8 @@
+libdir=/usr/lib/x86_64-linux-gnu/blis-pthread/
+includedir=/usr/include/x86_64-linux-gnu/blis-pthread
+
+Name: BLIS
+Description: BLAS-like Library Instantiation Software Framework - specific to SciPy CI job, needed until Debian ships blis.pc (see .github/workflows/linux_blas.yml)
+Version: 0.9.0-scipy-ci
+Libs: -L${libdir} -lblis
+Cflags: -I${includedir}
diff --git a/scipy/_build_utils/src/npy_cblas.h b/scipy/_build_utils/src/npy_cblas.h
index de65ad903284..8bc5496c9579 100644
--- a/scipy/_build_utils/src/npy_cblas.h
+++ b/scipy/_build_utils/src/npy_cblas.h
@@ -26,6 +26,21 @@ enum CBLAS_SIDE {CblasLeft=141, CblasRight=142};
 
 #define CBLAS_INDEX size_t  /* this may vary between platforms */
 
+#ifdef ACCELERATE_NEW_LAPACK
+    #if __MAC_OS_X_VERSION_MAX_ALLOWED < 130300
+        #ifdef HAVE_BLAS_ILP64
+            #error "Accelerate ILP64 support is only available with macOS 13.3 SDK or later"
+        #endif
+    #else
+        #define NO_APPEND_FORTRAN
+        #ifdef HAVE_BLAS_ILP64
+            #define BLAS_SYMBOL_SUFFIX $NEWLAPACK$ILP64
+        #else
+            #define BLAS_SYMBOL_SUFFIX $NEWLAPACK
+        #endif
+    #endif
+#endif
+
 #ifdef NO_APPEND_FORTRAN
 #define BLAS_FORTRAN_SUFFIX
 #else
diff --git a/scipy/meson.build b/scipy/meson.build
index c34bef307cfb..483884edbd87 100644
--- a/scipy/meson.build
+++ b/scipy/meson.build
@@ -460,11 +460,6 @@ dependency_map = {
   'PYBIND11': pybind11_dep,
 }
 
-# Reuse the names, so we ensure we don't lose the arguments wrapped in with
-# declare_dependency. Also, avoids changing `dependencies: blas` to blas_dep in other files.
-blas = blas_dep
-lapack = lapack_dep
-
 uses_mkl = blas.name().to_lower().startswith('mkl') or lapack.name().to_lower().startswith('mkl')
 uses_accelerate = blas.name().to_lower().startswith('accelerate') or lapack.name().to_lower().startswith('accelerate')
 use_g77_abi = uses_mkl or uses_accelerate or get_option('use-g77-abi')
@@ -484,6 +479,14 @@ else
   )
 endif
 
+# Reuse the names, so we ensure we don't lose the arguments wrapped in with
+# declare_dependency. Also, avoids changing `dependencies: blas` to blas_dep in other files.
+blas = blas_dep
+lapack = lapack_dep
+
+# End of BLAS/LAPACK handling
+
+
 scipy_dir = py3.get_install_dir() / 'scipy'
 
 # Generate version.py for sdist

From 6e8e7568ec5cc94938c9766b294dd74f7943efbc Mon Sep 17 00:00:00 2001
From: Ralf Gommers <ralf.gommers@gmail.com>
Date: Mon, 1 Jan 2024 21:01:55 +0100
Subject: [PATCH 05/22] WIP: ENH: enable ILP64 BLAS/LAPACK support again

This was left out initially when adding support for building with
Meson. The numpy.distutils based build supported ILP64 builds with
OpenBLAS and its `64_` symbol suffix scheme. We now add this back
and make it more generic, so that it also supports the `_64` scheme
of MKL as well as the `$NEWLAPACK_ILP64` scheme from Accelerate.
---
 scipy/_build_utils/int64.f2cmap.in            |   1 +
 scipy/_build_utils/src/npy_cblas.h            |   7 +-
 scipy/integrate/meson.build                   |  26 ++--
 scipy/interpolate/meson.build                 |  14 +-
 scipy/interpolate/src/_fitpackmodule.c        |   2 +-
 scipy/interpolate/src/dfitpack.pyf            |   2 +-
 scipy/linalg/meson.build                      |  68 +++++++++
 scipy/meson.build                             | 133 +++++++++++++-----
 scipy/odr/meson.build                         |   7 +-
 scipy/optimize/_trlib/meson.build             |   2 +-
 scipy/optimize/meson.build                    |   2 +-
 scipy/sparse/linalg/_eigen/arpack/meson.build |   7 +-
 scipy/spatial/meson.build                     |   2 +-
 scipy/special/meson.build                     |   3 +-
 tools/generate_f2pymod.py                     |  13 +-
 15 files changed, 226 insertions(+), 63 deletions(-)
 create mode 100644 scipy/_build_utils/int64.f2cmap.in

diff --git a/scipy/_build_utils/int64.f2cmap.in b/scipy/_build_utils/int64.f2cmap.in
new file mode 100644
index 000000000000..86ffa326b6e6
--- /dev/null
+++ b/scipy/_build_utils/int64.f2cmap.in
@@ -0,0 +1 @@
+{'integer': {'': '@int64_name@'}, 'logical': {'': '@int64_name@'}}
diff --git a/scipy/_build_utils/src/npy_cblas.h b/scipy/_build_utils/src/npy_cblas.h
index 8bc5496c9579..d68af2846bab 100644
--- a/scipy/_build_utils/src/npy_cblas.h
+++ b/scipy/_build_utils/src/npy_cblas.h
@@ -65,7 +65,6 @@ enum CBLAS_SIDE {CblasLeft=141, CblasRight=142};
 #define BLAS_FUNC_CONCAT(name,prefix,suffix,suffix2) prefix ## name ## suffix ## suffix2
 #define BLAS_FUNC_EXPAND(name,prefix,suffix,suffix2) BLAS_FUNC_CONCAT(name,prefix,suffix,suffix2)
 
-#define CBLAS_FUNC(name) BLAS_FUNC_EXPAND(name,BLAS_SYMBOL_PREFIX,,BLAS_SYMBOL_SUFFIX)
 /*
  * Use either the OpenBLAS scheme with the `64_` suffix behind the Fortran
  * compiler symbol mangling, or the MKL scheme (and upcoming
@@ -77,6 +76,12 @@ enum CBLAS_SIDE {CblasLeft=141, CblasRight=142};
 #define BLAS_FUNC(name) BLAS_FUNC_EXPAND(name,BLAS_SYMBOL_PREFIX,BLAS_SYMBOL_SUFFIX,BLAS_FORTRAN_SUFFIX)
 #endif
 
+/*
+ * Note that CBLAS doesn't include Fortran compiler symbol mangling, so ends up
+ * being the same in both schemes
+ */
+#define CBLAS_FUNC(name) BLAS_FUNC_EXPAND(name,BLAS_SYMBOL_PREFIX,,BLAS_SYMBOL_SUFFIX)
+
 #ifdef HAVE_BLAS_ILP64
 #define CBLAS_INT npy_int64
 #define CBLAS_INT_MAX NPY_MAX_INT64
diff --git a/scipy/integrate/meson.build b/scipy/integrate/meson.build
index 206d504f44b0..d6b5703e0551 100644
--- a/scipy/integrate/meson.build
+++ b/scipy/integrate/meson.build
@@ -37,54 +37,61 @@ quadpack_test_src = [
 
 mach_lib = static_library('mach_lib',
   mach_src,
-  fortran_args: fortran_ignore_warnings,
   gnu_symbol_visibility: 'hidden',
+  fortran_args: [fortran_ignore_warnings, _fflag_ilp64],
+)
+
+quadpack_lib = static_library('quadpack_lib',
+  quadpack_src,
+  fortran_args: [fortran_ignore_warnings, _fflag_ilp64],
 )
 
 lsoda_lib = static_library('lsoda_lib',
   lsoda_src,
-  fortran_args: fortran_ignore_warnings,
+  fortran_args: [fortran_ignore_warnings, _fflag_ilp64],
   override_options: ['b_lto=false'],
   gnu_symbol_visibility: 'hidden',
 )
 
 vode_lib = static_library('vode_lib',
   vode_src,
-  fortran_args: fortran_ignore_warnings,
+  fortran_args: [fortran_ignore_warnings, _fflag_ilp64],
   override_options: ['b_lto=false'],
   gnu_symbol_visibility: 'hidden',
 )
 
 dop_lib = static_library('dop_lib',
   dop_src,
-  fortran_args: fortran_ignore_warnings,
+  fortran_args: [fortran_ignore_warnings, _fflag_ilp64]
   gnu_symbol_visibility: 'hidden',
 )
 
 py3.extension_module('_quadpack',
   ['__quadpack.h', '__quadpack.c'],
-  dependencies: [np_dep, ccallback_dep],
+  dependencies: [np_dep, ccallback_dep, lapack_ilp64, ],
   install: true,
   subdir: 'scipy/integrate'
 )
 
+
 py3.extension_module('_odepack',
   '_odepackmodule.c',
   fortran_args: fortran_ignore_warnings,
   link_with: [lsoda_lib, mach_lib],
   link_args: version_link_args,
-  dependencies: [lapack_dep, np_dep],
+  dependencies: [lapack_ilp64, np_dep],
   install: true,
   link_language: 'fortran',
   subdir: 'scipy/integrate'
 )
 
+
 py3.extension_module('_vode',
   f2py_gen.process('vode.pyf'),
   link_with: [vode_lib],
   c_args: [Wno_unused_variable],
   link_args: version_link_args,
-  dependencies: [lapack_dep, blas_dep, fortranobject_dep],
+  dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep],
   install: true,
   link_language: 'fortran',
   subdir: 'scipy/integrate'
@@ -94,7 +101,8 @@ py3.extension_module('_lsoda',
   f2py_gen.process('lsoda.pyf'),
   link_with: [lsoda_lib, mach_lib],
   c_args: [Wno_unused_variable],
-  dependencies: [lapack_dep, fortranobject_dep],
+  dependencies: [lapack_ilp64, fortranobject_dep],
+  c_args: [numpy_nodepr_api, Wno_unused_variable],
   link_args: version_link_args,
   install: true,
   link_language: 'fortran',
@@ -125,7 +133,7 @@ py3.extension_module('_test_odeint_banded',
   link_with: [lsoda_lib, mach_lib],
   fortran_args: _fflag_Wno_unused_dummy_argument,
   link_args: version_link_args,
-  dependencies: [lapack_dep, fortranobject_dep],
+  dependencies: [lapack_ilp64, fortranobject_dep],
   install: true,
   link_language: 'fortran',
   subdir: 'scipy/integrate',
diff --git a/scipy/interpolate/meson.build b/scipy/interpolate/meson.build
index 72e2d20fd1dd..e4061a227bce 100644
--- a/scipy/interpolate/meson.build
+++ b/scipy/interpolate/meson.build
@@ -90,7 +90,7 @@ fitpack_src = [
 # TODO: Add flags for 64 bit ints
 fitpack_lib = static_library('fitpack_lib',
   fitpack_src,
-  fortran_args: _fflag_Wno_maybe_uninitialized,
+  fortran_args: [_fflag_Wno_maybe_uninitialized, _fflag_ilp64],
   override_options: ['b_lto=false'],
   gnu_symbol_visibility: 'hidden',
 )
@@ -150,9 +150,13 @@ py3.extension_module('_dierckx',
     subdir: 'scipy/interpolate'
 )
 
-# TODO: Add flags for 64 bit ints
-py3.extension_module('_fitpack',
+
+if use_ilp64
+  _c_args_fitpack += ['-DHAVE_BLAS_ILP64']
+endif
+_fitpack = py3.extension_module('_fitpack',
   ['src/_fitpackmodule.c'],
+  c_args: _c_args_fitpack,
   link_with: [fitpack_lib],
   include_directories: 'src/',
   dependencies: np_dep,
@@ -162,12 +166,13 @@ py3.extension_module('_fitpack',
   subdir: 'scipy/interpolate'
 )
 
+
 # TODO: Add flags for 64 bit ints
 py3.extension_module('_dfitpack',
   f2py_gen.process('src/dfitpack.pyf'),
   c_args: [Wno_unused_variable],
   link_args: version_link_args,
-  dependencies: [lapack_dep, fortranobject_dep],
+  dependencies: [lapack_ilp64, fortranobject_dep],
   link_with: [fitpack_lib],
   override_options: ['b_lto=false'],
   install: true,
@@ -175,6 +180,7 @@ py3.extension_module('_dfitpack',
   subdir: 'scipy/interpolate'
 )
 
+
 if use_pythran
   py3.extension_module('_rbfinterp_pythran',
     pythran_gen.process('_rbfinterp_pythran.py'),
diff --git a/scipy/interpolate/src/_fitpackmodule.c b/scipy/interpolate/src/_fitpackmodule.c
index e569fe93034f..59ebf4600e85 100644
--- a/scipy/interpolate/src/_fitpackmodule.c
+++ b/scipy/interpolate/src/_fitpackmodule.c
@@ -5,7 +5,7 @@
 
 static PyObject *fitpack_error;
 
-#ifdef HAVE_ILP64
+#ifdef HAVE_BLAS_ILP64
 
 #define F_INT npy_int64
 #define F_INT_NPY NPY_INT64
diff --git a/scipy/interpolate/src/dfitpack.pyf b/scipy/interpolate/src/dfitpack.pyf
index 829e1cdbbe7c..35b5d0846a73 100644
--- a/scipy/interpolate/src/dfitpack.pyf
+++ b/scipy/interpolate/src/dfitpack.pyf
@@ -13,7 +13,7 @@ python module _dfitpack ! in
 
   usercode '''
 
-#ifdef HAVE_ILP64
+#ifdef HAVE_BLAS_ILP64
 typedef npy_int64 F_INT;
 #else
 typedef int F_INT;
diff --git a/scipy/linalg/meson.build b/scipy/linalg/meson.build
index 95925a791cbc..b68e2a1adccf 100644
--- a/scipy/linalg/meson.build
+++ b/scipy/linalg/meson.build
@@ -101,6 +101,74 @@ py3.extension_module('_flapack',
   subdir: 'scipy/linalg'
 )
 
+# Add _fblas_64 and _flapack_64 if we're building with ILP64 support
+#
+# NOTE: what happened in the setup.py build was that we were linking LP64
+# libopenblas.so to `_fblas` and ILP64 `libopenblas64_.so` to `_fblas_64`
+# and used both at the same time. We never shipped wheels that way, it only
+# worked in a CI job. We are re-exporting the LP64 symbols in
+# `cython_blas`/`cython_lapack`, so we can't use only ILP64 even if we support
+# it in all SciPy code.
+# TODO: right now we're only detecting one BLAS library (like NumPy does), but
+#       we need two blas and two lapack dependency objects here.
+#       The ILP64 CI job in the 1.10.x branch downloads two OpenBLAS tarballs
+#       and then uses both in the build (search for `Download-OpenBLAS('1'))
+#       in azure-pipelines.yml if you want to check that).
+if use_ilp64
+  conf_data = configuration_data()
+  if cc.sizeof('long') == 8
+    conf_data.set('int64_name', 'long')
+  elif cc.sizeof('long long') == 8
+    conf_data.set('int64_name', 'long long')
+  else
+    error('Neither `long` nor `long long` is 64-bit, giving up.')
+  endif
+
+  int64_f2cmap = configure_file(
+    input: '../_build_utils/int64.f2cmap.in',
+    output: 'int64.f2cmap',
+    configuration: conf_data,
+    install: false,
+  )
+
+  f2py_ilp64_opts = ['--f2cmap', int64_f2cmap]
+
+  fblas64_module = custom_target('fblas64_module',
+    output: ['_fblas_64module.c', '_fblas_64-f2pywrappers.f'],
+    input: 'fblas_64.pyf.src',
+    command: [py3, generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@'] + f2py_ilp64_opts
+  )
+
+  py3.extension_module('_fblas_64',
+    fblas64_module,
+    c_args: numpy_nodepr_api,
+    fortran_args: _fflag_ilp64,
+    link_args: version_link_args,
+    dependencies: [lapack, blas, fortranobject_dep, g77_abi_wrappers],
+    install: true,
+    link_language: 'fortran',
+    subdir: 'scipy/linalg'
+  )
+
+  flapack64_module = custom_target('flapack64_module',
+    output: ['_flapack_64module.c', '_flapack_64-f2pywrappers.f'],
+    input: 'flapack_64.pyf.src',
+    command: [py3, generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@'] + f2py_ilp64_opts
+  )
+
+  py3.extension_module('_flapack_64',
+    flapack64_module,
+    c_args: [numpy_nodepr_api, Wno_empty_body],
+    fortran_args: _fflag_ilp64,
+    link_args: version_link_args,
+    dependencies: [lapack, blas, fortranobject_dep, g77_abi_wrappers],
+    install: true,
+    link_language: 'fortran',
+    subdir: 'scipy/linalg'
+  )
+endif
+
+
 # TODO: cblas/clapack are built *only* for ATLAS. Why? Is it still needed?
 
 # _decomp_interpolative
diff --git a/scipy/meson.build b/scipy/meson.build
index 483884edbd87..bcec6cfad8d6 100644
--- a/scipy/meson.build
+++ b/scipy/meson.build
@@ -221,20 +221,17 @@ f2py_gen = generator(generate_f2pymod,
 )
 
 
+# Start of BLAS/LAPACK detection
+
 blas_name = get_option('blas')
 lapack_name = get_option('lapack')
-# This is currently injected directly into CFLAGS/CXXFLAGS for wheel builds
-# (see cibuildwheel settings in pyproject.toml), but used by CI jobs already
 blas_symbol_suffix = get_option('blas-symbol-suffix')
-
 use_ilp64 = get_option('use-ilp64')
-if use_ilp64
-  blas_interface = ['interface: ilp64']
-else
-  blas_interface = ['interface: lp64']
-endif
-
 blas_order = get_option('blas-order')
+lapack_order = get_option('lapack-order')
+
+# Detect LP64 (32-bit) BLAS and LAPACK, we always need that
+blas_interface = ['interface: lp64']
 if blas_order == ['auto']
   blas_order = []
   if host_machine.system() == 'darwin'
@@ -245,7 +242,6 @@ if blas_order == ['auto']
   endif
   blas_order += ['openblas', 'flexiblas', 'blis', 'blas']
 endif
-lapack_order = get_option('lapack-order')
 if lapack_order == ['auto']
   lapack_order = []
   if host_machine.system() == 'darwin'
@@ -272,7 +268,7 @@ mkl_may_use_sdl = not use_ilp64 and _threading_opt in ['auto', 'iomp']
 
 # BLAS detection.
 #
-# First try scipy-openblas, and if found don't look for cblas or lapack, we
+# First try scipy-openblas, and if found don't look for blas/lapack, we
 # know what's inside the scipy-openblas wheels already.
 if blas_name == 'openblas' or blas_name == 'auto'
   blas = dependency('scipy-openblas', method: 'pkg-config', required: false)
@@ -284,7 +280,7 @@ if blas_name == 'auto'
   foreach _name : blas_order
     if _name == 'mkl'
       blas = dependency('mkl',
-        modules: ['cblas'] + blas_interface + mkl_opts,
+        modules: blas_interface + mkl_opts,
         required: false,  # may be required, but we need to emit a custom error message
         version: mkl_version_req,
       )
@@ -292,13 +288,10 @@ if blas_name == 'auto'
       # or missing it because no pkg-config installed. If so, we need to retry
       # with MKL SDL, and drop the version constraint (this always worked).
       if not blas.found() and mkl_may_use_sdl
-        blas = dependency('mkl', modules: ['cblas', 'sdl: true'], required: false)
+        blas = dependency('mkl', modules: ['sdl: true'], required: false)
       endif
     else
-      if _name == 'flexiblas' and use_ilp64
-        _name = 'flexiblas64'
-      endif
-      blas = dependency(_name, modules: ['cblas'] + blas_interface, required: false)
+      blas = dependency(_name, modules: blas_interface, required: false)
     endif
     if blas.found()
       break
@@ -306,17 +299,19 @@ if blas_name == 'auto'
   endforeach
 else
   if blas_name == 'mkl'
+    mkl_uses_sdl = false
     blas = dependency('mkl',
-      modules: ['cblas'] + blas_interface + mkl_opts,
+      modules: blas_interface + mkl_opts,
       required: false,
       version: mkl_version_req,
     )
     # Same deal as above - try again for MKL
     if not blas.found() and mkl_may_use_sdl
-      blas = dependency('mkl', modules: ['cblas', 'sdl: true'], required: false)
+      mkl_uses_sdl = true
+      blas = dependency('mkl', modules: ['sdl: true'], required: false)
     endif
   else
-    blas = dependency(blas_name, modules: ['cblas'] + blas_interface, required: false)
+    blas = dependency(blas_name, modules: blas_interface, required: false)
   endif
 endif
 
@@ -325,18 +320,8 @@ if not blas.found()
 endif
 
 _args_blas = []  # note: used for C and C++ via `blas_dep` below
-if use_ilp64
-  _args_blas += ['-DHAVE_BLAS_ILP64']
-  if 'openblas' in blas.name()
-    _args_blas += ['-DOPENBLAS_ILP64_NAMING_SCHEME']
-  endif
-endif
 if blas_symbol_suffix == 'auto'
-  if blas_name == 'scipy-openblas' and use_ilp64
-    blas_symbol_suffix = '64_'
-  else
-    blas_symbol_suffix = blas.get_variable('symbol_suffix', default_value: '')
-  endif
+  blas_symbol_suffix = blas.get_variable('symbol_suffix', default_value: '')
   message(f'BLAS symbol suffix: @blas_symbol_suffix@')
 endif
 if blas_symbol_suffix != ''
@@ -460,8 +445,10 @@ dependency_map = {
   'PYBIND11': pybind11_dep,
 }
 
-uses_mkl = blas.name().to_lower().startswith('mkl') or lapack.name().to_lower().startswith('mkl')
-uses_accelerate = blas.name().to_lower().startswith('accelerate') or lapack.name().to_lower().startswith('accelerate')
+blas_name = blas.name()
+lapack_name = lapack.name()
+uses_mkl = blas_name.to_lower().startswith('mkl')
+uses_accelerate = blas_name.to_lower().startswith('accelerate')
 use_g77_abi = uses_mkl or uses_accelerate or get_option('use-g77-abi')
 if use_g77_abi
   g77_abi_wrappers = static_library(
@@ -484,6 +471,60 @@ endif
 blas = blas_dep
 lapack = lapack_dep
 
+if use_ilp64
+  # Okay, we need ILP64 BLAS and LAPACK *in addition to LP64*. So we need to
+  # detect the ILP64 variants of the found LP64 libraries now.
+  _args_blas = []
+  blas_interface = ['interface: ilp64']
+  if blas_name == 'flexiblas'
+    blas_name = 'flexiblas64'
+  endif
+  _args_blas += ['-DHAVE_BLAS_ILP64']
+  if 'openblas' in blas_name
+    _args_blas += ['-DOPENBLAS_ILP64_NAMING_SCHEME']
+  endif
+
+  # Run the detection
+  if blas_name == 'mkl'
+    if mkl_uses_sdl
+      mkl_opts = ['sdl: true']
+    endif
+    blas_ilp64 = dependency('mkl', modules: [blas_interface, mkl_opts])
+    lapack_ilp64 = blas_ilp64
+  else
+    if blas_name == 'openblas'
+      # We cannot allow plain openblas here, that's already the LP64 library and
+      # will lead to problems (there is, as of now, no combined OpenBLAS build
+      # with 32 and 64 bit symbols)
+      blas_name = ['openblas64', 'openblas_ilp64']
+    endif
+    blas_ilp64 = dependency(blas_name, modules: blas_interface)
+    lapack_ilp64 = dependency(lapack_name, modules: ['lapack'] + blas_interface)
+  endif
+
+  # Pick up the symbol suffix, it may be auto-detected by Meson and different from LP64
+  if blas_symbol_suffix == 'auto'
+    if blas_name == 'scipy-openblas'
+      blas_symbol_suffix = '64_'
+    else
+      blas_symbol_suffix = blas_ilp64.get_variable('symbol_suffix', default_value: '')
+    endif
+    message(f'BLAS symbol suffix (ILP64): @blas_symbol_suffix@')
+  endif
+  if blas_symbol_suffix != ''
+    _args_blas += ['-DBLAS_SYMBOL_SUFFIX=' + blas_symbol_suffix]
+  endif
+  # Declare the ILP64 dependencies
+  blas_ilp64 = declare_dependency(
+    dependencies: [blas_ilp64],
+    compile_args: _args_blas,
+  )
+  lapack_ilp64 = declare_dependency(dependencies: [lapack_ilp64, blas_ilp64])
+else
+  blas_ilp64 = blas
+  lapack_ilp64 = lapack
+endif
+
 # End of BLAS/LAPACK handling
 
 
@@ -645,6 +686,32 @@ if ff.get_id() in ['intel-cl', 'intel-llvm-cl']
   endif
 endif
 
+_fflag_ilp64 = []
+f2py_ilp64_opts = []
+if use_ilp64
+  # Gfortran uses `-fdefault-integer-8` to switch to 64-bit integers by
+  # default, all other known compilers use `-i8`
+  _fflag_ilp64 = ff.get_supported_arguments(['-i8', '-fdefault-integer-8'])
+
+  conf_data = configuration_data()
+  if cc.sizeof('long') == 8
+    conf_data.set('int64_name', 'long')
+  elif cc.sizeof('long long') == 8
+    conf_data.set('int64_name', 'long long')
+  else
+    error('Neither `long` nor `long long` is 64-bit, giving up.')
+  endif
+
+  int64_f2cmap = configure_file(
+    input: '_build_utils/int64.f2cmap.in',
+    output: 'int64.f2cmap',
+    configuration: conf_data,
+    install: false,
+  )
+
+  f2py_ilp64_opts = ['--f2cmap', int64_f2cmap]
+endif
+
 # Deal with M_PI & friends; add `use_math_defines` to c_args or cpp_args
 # Cython doesn't always get this right itself (see, e.g., gh-16800), so
 # explicitly add the define as a compiler flag for Cython-generated code.
diff --git a/scipy/odr/meson.build b/scipy/odr/meson.build
index c7f53bc2365d..ebf27c7d6dc3 100644
--- a/scipy/odr/meson.build
+++ b/scipy/odr/meson.build
@@ -5,7 +5,10 @@ odrpack = static_library('odrpack',
     'odrpack/d_odr.f',
     'odrpack/dlunoc.f'
   ],
-  fortran_args: _fflag_Wno_conversion,  # silence "conversion from REAL(8) to INTEGER(4)"
+  fortran_args: [
+    _fflag_Wno_conversion,  # silence "conversion from REAL(8) to INTEGER(4)"
+    _fflag_ilp64
+  ],
   override_options: ['b_lto=false'],
   gnu_symbol_visibility: 'hidden',
 )
@@ -14,7 +17,7 @@ py3.extension_module('__odrpack',
   '__odrpack.c',
   link_with: odrpack,
   link_args: version_link_args,
-  dependencies: [blas_dep, np_dep],
+  dependencies: [blas_ilp64, np_dep]
   install: true,
   link_language: 'fortran',
   subdir: 'scipy/odr'
diff --git a/scipy/optimize/_trlib/meson.build b/scipy/optimize/_trlib/meson.build
index 9b15bb50fd23..734e84964f84 100644
--- a/scipy/optimize/_trlib/meson.build
+++ b/scipy/optimize/_trlib/meson.build
@@ -12,7 +12,7 @@ py3.extension_module('_trlib',
     '../../_lib',
     '../../_build_utils/src'
   ],
-  dependencies: [lapack_dep, blas_dep, np_dep],
+  dependencies: [lapack_ilp64, blas_ilp64, np_dep],
   link_args: version_link_args,
   install: true,
   subdir: 'scipy/optimize/_trlib'
diff --git a/scipy/optimize/meson.build b/scipy/optimize/meson.build
index 375f4c3aef79..a41d146c202d 100644
--- a/scipy/optimize/meson.build
+++ b/scipy/optimize/meson.build
@@ -67,7 +67,7 @@ py3.extension_module('_lbfgsb',
     '__lbfgsb.h',
     '__lbfgsb.c',
   ],
-  dependencies: [lapack_dep, blas_dep, np_dep],
+  dependencies: [lapack_ilp64, blas_ilp64],
   link_args: version_link_args,
   install: true,
   subdir: 'scipy/optimize'
diff --git a/scipy/sparse/linalg/_eigen/arpack/meson.build b/scipy/sparse/linalg/_eigen/arpack/meson.build
index 52c8ab968b22..f57653a61e48 100644
--- a/scipy/sparse/linalg/_eigen/arpack/meson.build
+++ b/scipy/sparse/linalg/_eigen/arpack/meson.build
@@ -89,7 +89,7 @@ _suppress_all_warnings = ff.get_supported_arguments('-w')
 
 arpack_lib = static_library('arpack_lib',
   arpack_sources,
-  fortran_args: [fortran_ignore_warnings, _suppress_all_warnings],
+  fortran_args: [fortran_ignore_warnings, _suppress_all_warnings, _fflag_ilp64],
   include_directories: ['ARPACK/SRC'],
   override_options: ['b_lto=false'],
   gnu_symbol_visibility: 'hidden',
@@ -98,14 +98,15 @@ arpack_lib = static_library('arpack_lib',
 arpack_module = custom_target('arpack_module',
   output: ['_arpackmodule.c', '_arpack-f2pywrappers.f'],
   input: 'arpack.pyf.src',
-  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@'] + f2py_freethreading_arg,
+  command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@'] + f2py_freethreading_arg + f2py_ilp64_opts,
 )
 
 _arpack = py3.extension_module('_arpack',
   arpack_module,
   link_with: arpack_lib,
   link_args: version_link_args,
-  dependencies: [lapack_dep, blas_dep, fortranobject_dep],
+  dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep], #, g77_abi_wrappers],
+  fortran_args: _fflag_ilp64,
   install: true,
   link_language: 'fortran',
   subdir: 'scipy/sparse/linalg/_eigen/arpack'
diff --git a/scipy/spatial/meson.build b/scipy/spatial/meson.build
index 1f46d1c7c53d..b37f9d0015d3 100644
--- a/scipy/spatial/meson.build
+++ b/scipy/spatial/meson.build
@@ -40,7 +40,7 @@ py3.extension_module('_qhull',
     'qhull_src/src'
   ],
   link_args: version_link_args,
-  dependencies: [np_dep],
+  dependencies: [lapack_ilp64, np_dep],
   install: true,
   subdir: 'scipy/spatial'
 )
diff --git a/scipy/special/meson.build b/scipy/special/meson.build
index 583c29c1f300..372aed27177d 100644
--- a/scipy/special/meson.build
+++ b/scipy/special/meson.build
@@ -123,7 +123,7 @@ py3.extension_module('_ufuncs',
   cpp_args: ['-DSP_SPECFUN_ERROR'],
   include_directories: ['../_lib', '../_build_utils/src'],
   dependencies: [
-    lapack_dep,
+    lapack_ilp64,
     npymath_lib,
     np_dep,
   ],
@@ -235,7 +235,6 @@ npz_files = [
     '_data_gsl',
     'tests/data/gsl/mathieu_ab.txt',
     'gsl',
-    'gsl.npz'
   ],
   [
     '_data_local',
diff --git a/tools/generate_f2pymod.py b/tools/generate_f2pymod.py
index e61524cc39b5..adc2b031370d 100644
--- a/tools/generate_f2pymod.py
+++ b/tools/generate_f2pymod.py
@@ -266,6 +266,8 @@ def main():
     parser.add_argument("--free-threading",
                         action=argparse.BooleanOptionalAction,
                         help="Whether to add --free-threading-compatible")
+    parser.add_argument("--f2cmap", type=str,
+                        help="Path to the f2cmap file")
     args = parser.parse_args()
 
     if not args.infile.endswith(('.pyf', '.pyf.src', '.f.src')):
@@ -290,10 +292,13 @@ def main():
 
     # Now invoke f2py to generate the C API module file
     if args.infile.endswith(('.pyf.src', '.pyf')):
-        p = subprocess.Popen(
-            ['f2py', fname_pyf, '--build-dir', outdir_abs] + nogil_arg,
-            stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=os.getcwd()
-        )
+        cmd = [sys.executable, '-m', 'numpy.f2py', fname_pyf,
+               '--build-dir', outdir_abs] + nogil_arg
+        if args.f2cmap:
+            cmd += ['--f2cmap', args.f2cmap]
+
+        p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
+                             stderr=subprocess.PIPE, cwd=os.getcwd())
         out, err = p.communicate()
         if not (p.returncode == 0):
             raise RuntimeError(f"Processing {fname_pyf} with f2py failed!\n"

From b4b7cb5d37ec1bc450a5681dbc807751e74aea03 Mon Sep 17 00:00:00 2001
From: Ralf Gommers <ralf.gommers@gmail.com>
Date: Tue, 2 Jan 2024 00:56:08 +0100
Subject: [PATCH 06/22] Squash several commits to simplify rebasing

DEBUG: enable macos job

BUG: ensure F77 ABI wrappers deal with BLAS symbol suffix correctly

This avoids build errors that look like:
```
../scipy/_build_utils/src/wrap_g77_abi_c.c:13:16: error: use of undeclared identifier 'cblas_cdotc_sub'
```
when one uses Accelerate with the `$NEWLAPACK` symbol suffix for example.

[ci skip]

WIP: ENH: more symbol renaming needed for BLAS symbol suffix support
---
 .github/workflows/macos.yml                   |   8 +-
 .../generate_blas_symbolsuffix_shims.py       | 200 ++++++++++++++++++
 scipy/_build_utils/meson.build                |   1 -
 scipy/integrate/meson.build                   |   7 +-
 scipy/interpolate/meson.build                 |   2 +
 scipy/linalg/meson.build                      |  38 ++--
 scipy/meson.build                             | 100 ++++-----
 scipy/odr/meson.build                         |   2 +-
 scipy/optimize/meson.build                    |   2 +-
 scipy/sparse/linalg/_propack/meson.build      |   2 +-
 scipy/special/meson.build                     |   4 +-
 tools/generate_f2pymod.py                     |   1 +
 12 files changed, 269 insertions(+), 98 deletions(-)
 create mode 100644 scipy/_build_utils/generate_blas_symbolsuffix_shims.py

diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index a4b0b5201e49..fdfce1cf8935 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - maintenance/**
+      - ci-blas
   pull_request:
     branches:
       - main
@@ -236,11 +237,16 @@ jobs:
       with:
         xcode-version: '14.3'
 
+    - name: Install gfortran with Homebrew
+      run: |
+        brew install gfortran
+        brew list
+        gfortran --version
+
     - name: Install dependencies
       run: |
         pip install -r requirements/all.txt
         pip install git+https://github.com/numpy/meson.git@main-numpymeson
-        brew install gfortran
 
     - name: Build against Accelerate (LP64)
       run: python dev.py build
diff --git a/scipy/_build_utils/generate_blas_symbolsuffix_shims.py b/scipy/_build_utils/generate_blas_symbolsuffix_shims.py
new file mode 100644
index 000000000000..92d288f6e0e9
--- /dev/null
+++ b/scipy/_build_utils/generate_blas_symbolsuffix_shims.py
@@ -0,0 +1,200 @@
+import re
+import os
+
+import numpy as np
+
+__all__ = ['blas_ilp64_pre_build_hook', 'generic_pre_build_hook',
+           'write_file_content']
+
+
+# See _fflag_lp64/ilp64 in scipy/meson.build for these
+# def get_fcompiler_ilp64_flags():
+# def get_fcompiler_macro_include_flags(path): 
+
+# Done in scipy/meson.build
+# def get_f2py_int64_options():
+
+
+def _blas_ilp64_pre_build_hook(outdir, prefix='', suffix=''):
+    if suffix:
+        if not suffix.endswith('_'):
+            # Symbol suffix has to end with '_' to be Fortran-compatible
+            raise RuntimeError("BLAS/LAPACK has incompatible symbol suffix: "
+                               "{!r}".format(suffix))
+
+        suffix = suffix[:-1]
+
+    # When symbol prefix/suffix is present, we have to patch sources
+
+    # Create name-mapping include files
+    include_name_f = 'blas64-prefix-defines.inc'
+    include_name_c = 'blas64-prefix-defines.h'
+    include_fn_f = os.path.join(outdir, include_name_f)
+    include_fn_c = os.path.join(outdir, include_name_c)
+
+    text = ""
+    for symbol in get_blas_lapack_symbols():
+        text += f'#define {symbol} {prefix}{symbol}_{suffix}\n'
+        text += f'#define {symbol.upper()} {prefix}{symbol}_{suffix}\n'
+
+        # Code generation may give source codes with mixed-case names
+        for j in (1, 2):
+            s = symbol[:j].lower() + symbol[j:].upper()
+            text += f'#define {s} {prefix}{symbol}_{suffix}\n'
+            s = symbol[:j].upper() + symbol[j:].lower()
+            text += f'#define {s} {prefix}{symbol}_{suffix}\n'
+
+    write_file_content(include_fn_f, text)
+
+    ctext = re.sub(r'^#define (.*) (.*)$', r'#define \1_ \2_', text, flags=re.M)
+    write_file_content(include_fn_c, text + "\n" + ctext)
+
+    # Patch sources to include it
+    def patch_source(filename, old_text):
+        text = f'#include "{include_name_f}"\n'
+        text += old_text
+        return text
+
+    # TODO: update source file names
+    #return generic_pre_build_hook(patch_source_func=patch_source,
+    #                             source_fnpart="_blas64")
+
+
+def generic_pre_build_hook(cmd, ext, fcompiler_flags, patch_source_func=None,
+                           source_fnpart=None):
+    """
+    Pre-build hook for adding compiler flags and patching sources.
+
+    Parameters
+    ----------
+    cmd : distutils.core.Command
+        Hook input. Current distutils command (build_clib or build_ext).
+    ext : dict or numpy.distutils.extension.Extension
+        Hook input. Configuration information for library (dict, build_clib)
+        or extension (numpy.distutils.extension.Extension, build_ext).
+    fcompiler_flags : dict
+        Dictionary of ``{'compiler_name': ['-flag1', ...]}`` containing
+        compiler flags to set.
+    patch_source_func : callable, optional
+        Function patching sources, see `_generic_patch_sources` below.
+    source_fnpart : str, optional
+        String to append to the modified file basename before extension.
+
+    """
+    # Mangle sources
+    if patch_source_func is not None:
+        build_info.setdefault('depends', []).extend(build_info['sources'])
+        new_sources = _generic_patch_sources(build_info['sources'], patch_source_func,
+                                             source_fnpart)
+        build_info['sources'][:] = new_sources
+
+
+
+def _generic_patch_sources(filenames, patch_source_func, source_fnpart, root_dir=None):
+    """
+    Patch Fortran sources, creating new source files.
+
+    Parameters
+    ----------
+    filenames : list
+        List of Fortran source files to patch.
+        Files not ending in ``.f`` or ``.f90`` are left unaltered.
+    patch_source_func : callable(filename, old_contents) -> new_contents
+        Function to apply to file contents, returning new file contents
+        as a string.
+    source_fnpart : str
+        String to append to the modified file basename before extension.
+    root_dir : str, optional
+        Source root directory. Default: cwd
+
+    Returns
+    -------
+    new_filenames : list
+        List of names of the newly created patched sources.
+
+    """
+    new_filenames = []
+
+    if root_dir is None:
+        root_dir = os.getcwd()
+
+    root_dir = os.path.abspath(root_dir)
+    src_dir = os.path.join(root_dir, _get_build_src_dir())
+
+    for src in filenames:
+        base, ext = os.path.splitext(os.path.basename(src))
+
+        if ext not in ('.f', '.f90'):
+            new_filenames.append(src)
+            continue
+
+        with open(src) as fsrc:
+            text = patch_source_func(src, fsrc.read())
+
+        # Generate useful target directory name under src_dir
+        src_path = os.path.abspath(os.path.dirname(src))
+
+        for basedir in [src_dir, root_dir]:
+            if os.path.commonpath([src_path, basedir]) == basedir:
+                rel_path = os.path.relpath(src_path, basedir)
+                break
+        else:
+            raise ValueError(f"{src!r} not under {root_dir!r}")
+
+        dst = os.path.join(src_dir, rel_path, base + source_fnpart + ext)
+        write_file_content(dst, text)
+
+        new_filenames.append(dst)
+
+    return new_filenames
+
+
+def write_file_content(filename, content):
+    """
+    Write content to file, but only if it differs from the current one.
+    """
+    if os.path.isfile(filename):
+        with open(filename) as f:
+            old_content = f.read()
+
+        if old_content == content:
+            return
+
+    dirname = os.path.dirname(filename)
+    if not os.path.isdir(dirname):
+        os.makedirs(dirname)
+
+    with open(filename, 'w') as f:
+        f.write(content)
+
+
+def get_blas_lapack_symbols():
+    cached = getattr(get_blas_lapack_symbols, 'cached', None)
+    if cached is not None:
+        return cached
+
+    # Obtain symbol list from Cython Blas/Lapack interface
+    srcdir = os.path.join(os.path.dirname(__file__), os.pardir, 'linalg')
+
+    symbols = []
+
+    # Get symbols from the generated files
+    for fn in ['cython_blas_signatures.txt', 'cython_lapack_signatures.txt']:
+        with open(os.path.join(srcdir, fn)) as f:
+            for line in f:
+                m = re.match(r"^\s*[a-z]+\s+([a-z0-9]+)\(", line)
+                if m:
+                    symbols.append(m.group(1))
+
+    # Get the rest from the generator script
+    # (we cannot import it directly here, so use exec)
+    sig_fn = os.path.join(srcdir, '_cython_signature_generator.py')
+    with open(sig_fn) as f:
+        code = f.read()
+    ns = {'__name__': '<module>'}
+    exec(code, ns)
+    symbols.extend(ns['blas_exclusions'])
+    symbols.extend(ns['lapack_exclusions'])
+
+    get_blas_lapack_symbols.cached = tuple(sorted(set(symbols)))
+    return get_blas_lapack_symbols.cached
diff --git a/scipy/_build_utils/meson.build b/scipy/_build_utils/meson.build
index c9de2910900a..b73d50969008 100644
--- a/scipy/_build_utils/meson.build
+++ b/scipy/_build_utils/meson.build
@@ -11,7 +11,6 @@ if generate_blas_wrappers
 
   blas_lapack_wrapper_lib = static_library('blas_lapack_wrapper_lib',
     blas_lapack_wrappers,
-    c_args: numpy_nodepr_api,
     dependencies: [blas_dep, lapack_dep, np_dep, py3_dep],
     include_directories: ['../linalg/', './src'],
     gnu_symbol_visibility: 'hidden',
diff --git a/scipy/integrate/meson.build b/scipy/integrate/meson.build
index d6b5703e0551..cf12c79c5347 100644
--- a/scipy/integrate/meson.build
+++ b/scipy/integrate/meson.build
@@ -41,10 +41,6 @@ mach_lib = static_library('mach_lib',
   fortran_args: [fortran_ignore_warnings, _fflag_ilp64],
 )
 
-quadpack_lib = static_library('quadpack_lib',
-  quadpack_src,
-  fortran_args: [fortran_ignore_warnings, _fflag_ilp64],
-)
 
 lsoda_lib = static_library('lsoda_lib',
   lsoda_src,
@@ -62,7 +58,7 @@ vode_lib = static_library('vode_lib',
 
 dop_lib = static_library('dop_lib',
   dop_src,
-  fortran_args: [fortran_ignore_warnings, _fflag_ilp64]
+  fortran_args: [fortran_ignore_warnings, _fflag_ilp64],
   gnu_symbol_visibility: 'hidden',
 )
 
@@ -102,7 +98,6 @@ py3.extension_module('_lsoda',
   link_with: [lsoda_lib, mach_lib],
   c_args: [Wno_unused_variable],
   dependencies: [lapack_ilp64, fortranobject_dep],
-  c_args: [numpy_nodepr_api, Wno_unused_variable],
   link_args: version_link_args,
   install: true,
   link_language: 'fortran',
diff --git a/scipy/interpolate/meson.build b/scipy/interpolate/meson.build
index e4061a227bce..5bce33ff276f 100644
--- a/scipy/interpolate/meson.build
+++ b/scipy/interpolate/meson.build
@@ -151,9 +151,11 @@ py3.extension_module('_dierckx',
 )
 
 
+_c_args_fitpack = []
 if use_ilp64
   _c_args_fitpack += ['-DHAVE_BLAS_ILP64']
 endif
+
 _fitpack = py3.extension_module('_fitpack',
   ['src/_fitpackmodule.c'],
   c_args: _c_args_fitpack,
diff --git a/scipy/linalg/meson.build b/scipy/linalg/meson.build
index b68e2a1adccf..16449340c588 100644
--- a/scipy/linalg/meson.build
+++ b/scipy/linalg/meson.build
@@ -66,6 +66,7 @@ fblas_module = custom_target('fblas_module',
 # LAPACK - we have historically put these in `_fblas`.
 py3.extension_module('_fblas',
   fblas_module,
+  fortran_args: _fflag_lp64,
   link_args: version_link_args,
   dependencies: [lapack_dep, blas_dep, fortranobject_dep],
   install: true,
@@ -95,6 +96,7 @@ flapack_module = custom_target('flapack_module',
 py3.extension_module('_flapack',
   flapack_module,
   c_args: [Wno_empty_body],
+  fortran_args: _fflag_lp64,
   link_args: version_link_args,
   dependencies: [lapack_dep, blas_dep, fortranobject_dep],
   install: true,
@@ -115,36 +117,23 @@ py3.extension_module('_flapack',
 #       and then uses both in the build (search for `Download-OpenBLAS('1'))
 #       in azure-pipelines.yml if you want to check that).
 if use_ilp64
-  conf_data = configuration_data()
-  if cc.sizeof('long') == 8
-    conf_data.set('int64_name', 'long')
-  elif cc.sizeof('long long') == 8
-    conf_data.set('int64_name', 'long long')
-  else
-    error('Neither `long` nor `long long` is 64-bit, giving up.')
-  endif
-
-  int64_f2cmap = configure_file(
-    input: '../_build_utils/int64.f2cmap.in',
-    output: 'int64.f2cmap',
-    configuration: conf_data,
-    install: false,
-  )
-
-  f2py_ilp64_opts = ['--f2cmap', int64_f2cmap]
-
   fblas64_module = custom_target('fblas64_module',
     output: ['_fblas_64module.c', '_fblas_64-f2pywrappers.f'],
     input: 'fblas_64.pyf.src',
-    command: [py3, generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@'] + f2py_ilp64_opts
+    command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@'] + f2py_ilp64_opts,
+    depend_files:
+      [
+        'fblas_l1.pyf.src',
+        'fblas_l2.pyf.src',
+        'fblas_l3.pyf.src',
+      ]
   )
 
   py3.extension_module('_fblas_64',
     fblas64_module,
-    c_args: numpy_nodepr_api,
     fortran_args: _fflag_ilp64,
     link_args: version_link_args,
-    dependencies: [lapack, blas, fortranobject_dep, g77_abi_wrappers],
+    dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep, g77_abi_wrappers],
     install: true,
     link_language: 'fortran',
     subdir: 'scipy/linalg'
@@ -153,15 +142,15 @@ if use_ilp64
   flapack64_module = custom_target('flapack64_module',
     output: ['_flapack_64module.c', '_flapack_64-f2pywrappers.f'],
     input: 'flapack_64.pyf.src',
-    command: [py3, generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@'] + f2py_ilp64_opts
+    command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@'] + f2py_ilp64_opts
   )
 
   py3.extension_module('_flapack_64',
     flapack64_module,
-    c_args: [numpy_nodepr_api, Wno_empty_body],
+    c_args: [Wno_empty_body],
     fortran_args: _fflag_ilp64,
     link_args: version_link_args,
-    dependencies: [lapack, blas, fortranobject_dep, g77_abi_wrappers],
+    dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep, g77_abi_wrappers],
     install: true,
     link_language: 'fortran',
     subdir: 'scipy/linalg'
@@ -171,6 +160,7 @@ endif
 
 # TODO: cblas/clapack are built *only* for ATLAS. Why? Is it still needed?
 
+
 # _decomp_interpolative
 py3.extension_module('_decomp_interpolative',
   linalg_cython_gen.process('_decomp_interpolative.pyx'),
diff --git a/scipy/meson.build b/scipy/meson.build
index bcec6cfad8d6..44253100a208 100644
--- a/scipy/meson.build
+++ b/scipy/meson.build
@@ -85,7 +85,12 @@ else
   _incdir_numpy_abs = incdir_numpy
 endif
 inc_np = include_directories(incdir_numpy)
-np_dep = declare_dependency(include_directories: inc_np)
+# Don't use the deprecated NumPy C API. Define this to a fixed version instead of
+# NPY_API_VERSION in order not to break compilation for released SciPy versions
+# when NumPy introduces a new deprecation.
+numpy_nodepr_api = ['-DNPY_NO_DEPRECATED_API=NPY_1_9_API_VERSION']
+np_dep = declare_dependency(include_directories: inc_np, compile_args: numpy_nodepr_api)
+
 
 incdir_f2py = incdir_numpy / '..' / '..' / 'f2py' / 'src'
 inc_f2py = include_directories(incdir_f2py)
@@ -138,7 +143,6 @@ cpp_args_pythran = [
 # Share this object across multiple modules.
 fortranobject_lib = static_library('_fortranobject',
   fortranobject_c,
-  c_args: numpy_nodepr_api,
   dependencies: py3_dep,
   include_directories: [inc_np, inc_f2py],
   gnu_symbol_visibility: 'hidden',
@@ -324,12 +328,15 @@ if blas_symbol_suffix == 'auto'
   blas_symbol_suffix = blas.get_variable('symbol_suffix', default_value: '')
   message(f'BLAS symbol suffix: @blas_symbol_suffix@')
 endif
+_blas_incdir = []
 if blas_symbol_suffix != ''
   _args_blas += ['-DBLAS_SYMBOL_SUFFIX=' + blas_symbol_suffix]
+  _blas_incdir = ['.']  # for the generated symbol rename shims in the build dir
 endif
 blas_dep = declare_dependency(
   dependencies: [blas],
   compile_args: _args_blas,
+  include_directories: _blas_incdir,
 )
 
 # LAPACK detection
@@ -357,19 +364,6 @@ lapack_dep = declare_dependency(dependencies: [lapack, blas_dep])
 
 
 
-###############################################
-# TODO: 64-bit BLAS and LAPACK
-#
-# Note that this works as long as BLAS and LAPACK are detected properly via
-# pkg-config. By default we look for OpenBLAS, other libraries can be configured via
-# `meson configure -Dblas=blas -Dlapack=lapack` (example to build with Netlib
-# BLAS and LAPACK).
-# For MKL and for auto-detecting one of multiple libs, we'll need a custom
-# dependency in Meson (like is done for scalapack) - see
-# https://github.com/mesonbuild/meson/issues/2835
-blas_name = get_option('blas')
-lapack_name = get_option('lapack')
-
 macOS13_3_or_later = false
 if host_machine.system() == 'darwin'
   r = run_command('xcrun', '-sdk', 'macosx', '--show-sdk-version', check: true)
@@ -393,27 +387,7 @@ if blas_name == 'accelerate'
   accelerate_flag = '-a'
 endif
 
-# First try scipy-openblas, and if found don't look for cblas or lapack, we
-# know what's inside the scipy-openblas wheels already.
-if blas_name == 'openblas' or blas_name == 'auto'
-  blas = dependency('scipy-openblas', method: 'pkg-config', required: false)
-  if blas.found()
-    blas_name = 'scipy-openblas'
-    generate_blas_wrappers = true
-  endif
-endif
 
-# pkg-config uses a lower-case name while CMake uses a capitalized name, so try
-# that too to make the fallback detection with CMake work
-if blas_name == 'openblas'
-  blas = dependency(['openblas', 'OpenBLAS'])
-elif blas_name != 'scipy-openblas'  # if so, we found it already
-  blas = dependency(blas_name)
-endif
-blas_dep = declare_dependency(
-  dependencies: blas,
-  compile_args: _args_blas_lapack
-)
 if blas_name == 'blas'
   # Netlib BLAS has a separate `libcblas.so` which we use directly in the g77
   # ABI wrappers, so detect it and error out if we cannot find it.
@@ -425,19 +399,6 @@ else
   cblas = []
 endif
 
-if 'mkl' in blas.name() or blas.name().to_lower() == 'accelerate' or blas_name == 'scipy-openblas'
-  # For these libraries we know that they contain LAPACK, and it's desirable to
-  # use that - no need to run the full detection twice.
-  lapack = blas
-elif lapack_name == 'openblas'
-  lapack = dependency(['openblas', 'OpenBLAS'])
-else
-  lapack = dependency(lapack_name)
-endif
-lapack_dep = declare_dependency(
-  dependencies: lapack,
-  compile_args: _args_blas_lapack
-)
 
 dependency_map = {
   'BLAS': blas,
@@ -511,13 +472,16 @@ if use_ilp64
     endif
     message(f'BLAS symbol suffix (ILP64): @blas_symbol_suffix@')
   endif
+  _blas_incdir = []
   if blas_symbol_suffix != ''
     _args_blas += ['-DBLAS_SYMBOL_SUFFIX=' + blas_symbol_suffix]
+    _blas_incdir = ['.']
   endif
   # Declare the ILP64 dependencies
   blas_ilp64 = declare_dependency(
     dependencies: [blas_ilp64],
     compile_args: _args_blas,
+    include_directories: _blas_incdir,
   )
   lapack_ilp64 = declare_dependency(dependencies: [lapack_ilp64, blas_ilp64])
 else
@@ -555,9 +519,9 @@ python_sources = [
   '__init__.py',
   '_distributor_init.py',
   'conftest.py',
-  'linalg.pxd',
-  'optimize.pxd',
-  'special.pxd',
+ # 'linalg.pxd',
+ # 'optimize.pxd',
+ # 'special.pxd',
 ]
 
 if fs.exists('_distributor_init_local.py')
@@ -677,22 +641,27 @@ fortran_ignore_warnings = ff.get_supported_arguments(
 
 # Intel Fortran (ifort) does not run the preprocessor by default, if Fortran
 # code uses preprocessor statements, add this compile flag to it.
-_fflag_fpp = []
-if ff.get_id() in ['intel-cl', 'intel-llvm-cl']
-  if is_windows
-    _fflag_fpp = ff.get_supported_arguments('/fpp')
-  else
-    _fflag_fpp = ff.get_supported_arguments('-fpp')
-  endif
+
+# Gfortran does run the preprocessor for .F files, and PROPACK is the only
+# component which needs the preprocessor (unless we need symbol renaming for
+# blas_symbol_suffix).
+_fflag_preprocess = []
+_gfortran_preprocess = ['-cpp', '-ffree-line-length-none', '-ffixed-line-length-none']
+if ff.has_multi_arguments(_gfortran_preprocess)
+  _fflag_preprocess = _gfortran_preprocess
+else
+  _fflag_preprocess = ff.first_supported_argument(['-fpp', '/fpp', 'cpp'])
 endif
 
+_fflag_lp64 = []
 _fflag_ilp64 = []
 f2py_ilp64_opts = []
 if use_ilp64
-  # Gfortran uses `-fdefault-integer-8` to switch to 64-bit integers by
+  # Gfortran and Clang use `-fdefault-integer-8` to switch to 64-bit integers by
   # default, all other known compilers use `-i8`
-  _fflag_ilp64 = ff.get_supported_arguments(['-i8', '-fdefault-integer-8'])
+  _fflag_ilp64 = ff.first_supported_argument(['-fdefault-integer-8', '-i8'])
 
+  # Write out a mapping file for f2py for defaulting to ILP64
   conf_data = configuration_data()
   if cc.sizeof('long') == 8
     conf_data.set('int64_name', 'long')
@@ -701,17 +670,24 @@ if use_ilp64
   else
     error('Neither `long` nor `long long` is 64-bit, giving up.')
   endif
-
   int64_f2cmap = configure_file(
     input: '_build_utils/int64.f2cmap.in',
     output: 'int64.f2cmap',
     configuration: conf_data,
     install: false,
   )
-
   f2py_ilp64_opts = ['--f2cmap', int64_f2cmap]
 endif
 
+if blas_symbol_suffix != ''
+  # We need to patch source files that use BLAS/LAPACK symbols.
+  # In addition, we now need to enable the Fortran preprocessor on all targets
+  # that depend on BLAS/LAPACK
+  # Note: this came from `scipy/build_utils/_fortran.py` in the distutils build.
+  _fflag_lp64 += _fflag_preprocess  # TODO: propagate _fflag_lp64
+  _fflag_ilp64 += _fflag_preprocess
+endif
+
 # Deal with M_PI & friends; add `use_math_defines` to c_args or cpp_args
 # Cython doesn't always get this right itself (see, e.g., gh-16800), so
 # explicitly add the define as a compiler flag for Cython-generated code.
diff --git a/scipy/odr/meson.build b/scipy/odr/meson.build
index ebf27c7d6dc3..6ed10624194c 100644
--- a/scipy/odr/meson.build
+++ b/scipy/odr/meson.build
@@ -17,7 +17,7 @@ py3.extension_module('__odrpack',
   '__odrpack.c',
   link_with: odrpack,
   link_args: version_link_args,
-  dependencies: [blas_ilp64, np_dep]
+  dependencies: [blas_ilp64, np_dep],
   install: true,
   link_language: 'fortran',
   subdir: 'scipy/odr'
diff --git a/scipy/optimize/meson.build b/scipy/optimize/meson.build
index a41d146c202d..5247e5f1c5e0 100644
--- a/scipy/optimize/meson.build
+++ b/scipy/optimize/meson.build
@@ -67,7 +67,7 @@ py3.extension_module('_lbfgsb',
     '__lbfgsb.h',
     '__lbfgsb.c',
   ],
-  dependencies: [lapack_ilp64, blas_ilp64],
+  dependencies: [lapack_ilp64, blas_ilp64, np_dep],
   link_args: version_link_args,
   install: true,
   subdir: 'scipy/optimize'
diff --git a/scipy/sparse/linalg/_propack/meson.build b/scipy/sparse/linalg/_propack/meson.build
index d33cdc0e7646..b6b5dd94d419 100644
--- a/scipy/sparse/linalg/_propack/meson.build
+++ b/scipy/sparse/linalg/_propack/meson.build
@@ -94,7 +94,7 @@ foreach ele: elements
       fortran_ignore_warnings,
       _fflag_Wno_intrinsic_shadow,
       _fflag_Wno_uninitialized,
-      _fflag_fpp,
+      _fflag_preprocess,
     ],
     gnu_symbol_visibility: 'hidden',
   )
diff --git a/scipy/special/meson.build b/scipy/special/meson.build
index 372aed27177d..d00d44583566 100644
--- a/scipy/special/meson.build
+++ b/scipy/special/meson.build
@@ -223,7 +223,6 @@ py3.install_sources(
 )
 
 # Must use `custom_target`, because `py3.install_sources` does not work with
-# generated sources - see https://github.com/mesonbuild/meson/issues/7372
 npz_files = [
   [
     '_data_boost',
@@ -235,6 +234,7 @@ npz_files = [
     '_data_gsl',
     'tests/data/gsl/mathieu_ab.txt',
     'gsl',
+    'gsl.npz'
   ],
   [
     '_data_local',
@@ -258,6 +258,8 @@ foreach npz_file: npz_files
   )
 endforeach
 
+
+
 # Headers for special functions in `xsf` library are included in
 # both build and install dirs for development purposes. Not public!
 
diff --git a/tools/generate_f2pymod.py b/tools/generate_f2pymod.py
index adc2b031370d..aaedad2bd26f 100644
--- a/tools/generate_f2pymod.py
+++ b/tools/generate_f2pymod.py
@@ -9,6 +9,7 @@
 import os
 import re
 import subprocess
+import sys
 
 
 # START OF CODE VENDORED FROM `numpy.distutils.from_template`

From 2d90949aa1c32c79017d5d0792161a71bbf2a841 Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Sat, 22 Mar 2025 22:15:14 +0100
Subject: [PATCH 07/22] BLD: linalg, sparse/linalg: link with g77_abi_wrappers

---
 scipy/integrate/meson.build                   |  2 --
 scipy/linalg/meson.build                      | 12 +++++++++---
 scipy/sparse/linalg/_eigen/arpack/meson.build |  4 ++--
 3 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/scipy/integrate/meson.build b/scipy/integrate/meson.build
index cf12c79c5347..e76f864d7956 100644
--- a/scipy/integrate/meson.build
+++ b/scipy/integrate/meson.build
@@ -69,7 +69,6 @@ py3.extension_module('_quadpack',
   subdir: 'scipy/integrate'
 )
 
-
 py3.extension_module('_odepack',
   '_odepackmodule.c',
   fortran_args: fortran_ignore_warnings,
@@ -81,7 +80,6 @@ py3.extension_module('_odepack',
   subdir: 'scipy/integrate'
 )
 
-
 py3.extension_module('_vode',
   f2py_gen.process('vode.pyf'),
   link_with: [vode_lib],
diff --git a/scipy/linalg/meson.build b/scipy/linalg/meson.build
index 16449340c588..c5abda2be2ae 100644
--- a/scipy/linalg/meson.build
+++ b/scipy/linalg/meson.build
@@ -50,7 +50,7 @@ linalg_cython_gen = generator(cython,
 
 # fblas
 fblas_module = custom_target('fblas_module',
-  output: ['_fblasmodule.c'],
+  output: ['_fblasmodule.c', '_fblas-f2pywrappers.f'],
   input: 'fblas.pyf.src',
   command: [generate_f2pymod, '@INPUT@', '-o', '@OUTDIR@'] + f2py_freethreading_arg,
   depend_files:
@@ -69,7 +69,9 @@ py3.extension_module('_fblas',
   fortran_args: _fflag_lp64,
   link_args: version_link_args,
   dependencies: [lapack_dep, blas_dep, fortranobject_dep],
+  link_with: [g77_abi_wrappers],
   install: true,
+  link_language: 'fortran',
   subdir: 'scipy/linalg'
 )
 
@@ -131,9 +133,11 @@ if use_ilp64
 
   py3.extension_module('_fblas_64',
     fblas64_module,
+    #['_fblas_64module.c'],
     fortran_args: _fflag_ilp64,
     link_args: version_link_args,
-    dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep, g77_abi_wrappers],
+    dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep], #g77_abi_wrappers],
+    link_with: [g77_abi_wrappers],
     install: true,
     link_language: 'fortran',
     subdir: 'scipy/linalg'
@@ -147,10 +151,12 @@ if use_ilp64
 
   py3.extension_module('_flapack_64',
     flapack64_module,
+    #['_flapack_64module.c'],
     c_args: [Wno_empty_body],
     fortran_args: _fflag_ilp64,
     link_args: version_link_args,
-    dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep, g77_abi_wrappers],
+    dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep], #g77_abi_wrappers],
+    link_with: [g77_abi_wrappers],
     install: true,
     link_language: 'fortran',
     subdir: 'scipy/linalg'
diff --git a/scipy/sparse/linalg/_eigen/arpack/meson.build b/scipy/sparse/linalg/_eigen/arpack/meson.build
index f57653a61e48..876b19bbb8c5 100644
--- a/scipy/sparse/linalg/_eigen/arpack/meson.build
+++ b/scipy/sparse/linalg/_eigen/arpack/meson.build
@@ -103,9 +103,9 @@ arpack_module = custom_target('arpack_module',
 
 _arpack = py3.extension_module('_arpack',
   arpack_module,
-  link_with: arpack_lib,
+  link_with: [arpack_lib, g77_abi_wrappers],
   link_args: version_link_args,
-  dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep], #, g77_abi_wrappers],
+  dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep],
   fortran_args: _fflag_ilp64,
   install: true,
   link_language: 'fortran',

From 986e29a04a17ffbff80ec54e181565139cb1a3e5 Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Tue, 11 Mar 2025 18:09:01 +0000
Subject: [PATCH 08/22] BLD: interpolate: build FITPACK with 32- or 64-bit ints

---
 scipy/interpolate/meson.build | 27 +++++++++++++++++++++------
 scipy/meson.build             |  2 +-
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/scipy/interpolate/meson.build b/scipy/interpolate/meson.build
index 5bce33ff276f..a4cc26aa9dbe 100644
--- a/scipy/interpolate/meson.build
+++ b/scipy/interpolate/meson.build
@@ -87,10 +87,15 @@ fitpack_src = [
   'fitpack/pardtc.f'
 ]
 
-# TODO: Add flags for 64 bit ints
+if use_ilp64
+  _fflag_intsize = _fflag_ilp64
+else
+  _fflag_intsize = _fflag_lp64
+endif
+
 fitpack_lib = static_library('fitpack_lib',
   fitpack_src,
-  fortran_args: [_fflag_Wno_maybe_uninitialized, _fflag_ilp64],
+  fortran_args: [_fflag_Wno_maybe_uninitialized, _fflag_intsize],
   override_options: ['b_lto=false'],
   gnu_symbol_visibility: 'hidden',
 )
@@ -150,6 +155,9 @@ py3.extension_module('_dierckx',
     subdir: 'scipy/interpolate'
 )
 
+# Build _fitpack and dfitpack extensions: both are FITPACK wrappers.
+# XXX: some functions from dfitpack use the F_INT macro defined in dfitpack.pyf, while
+#      others rely on the build flags only. Consider cleaning this up at some point.
 
 _c_args_fitpack = []
 if use_ilp64
@@ -168,13 +176,20 @@ _fitpack = py3.extension_module('_fitpack',
   subdir: 'scipy/interpolate'
 )
 
+if use_ilp64
+   # generator only accepts strings, not files
+   f2c_map_file = f2py_ilp64_opts[1]
+   extra_arg = f2py_ilp64_opts[0] + '=' + fs.parent(f2c_map_file) / fs.name(f2c_map_file)
+  _dfitpackmodule_obj = f2py_gen.process('src/dfitpack.pyf', extra_args: extra_arg)
+else
+  _dfitpackmodule_obj = f2py_gen.process('src/dfitpack.pyf')
+endif
 
-# TODO: Add flags for 64 bit ints
 py3.extension_module('_dfitpack',
-  f2py_gen.process('src/dfitpack.pyf'),
-  c_args: [Wno_unused_variable],
+  _dfitpackmodule_obj,
+  c_args: [Wno_unused_variable] + _c_args_fitpack,
   link_args: version_link_args,
-  dependencies: [lapack_ilp64, fortranobject_dep],
+  dependencies: [fortranobject_dep],
   link_with: [fitpack_lib],
   override_options: ['b_lto=false'],
   install: true,
diff --git a/scipy/meson.build b/scipy/meson.build
index 44253100a208..8c2e457ca37c 100644
--- a/scipy/meson.build
+++ b/scipy/meson.build
@@ -220,7 +220,7 @@ endif
 # 2. targets with #include's (due to no `depend_files` - see feature request
 #    at meson#8295)
 f2py_gen = generator(generate_f2pymod,
-  arguments : ['@INPUT@', '-o', '@BUILD_DIR@'] + f2py_freethreading_arg,
+  arguments : ['@INPUT@', '-o', '@BUILD_DIR@', '@EXTRA_ARGS@'] + f2py_freethreading_arg,
   output : ['_@BASENAME@module.c', '_@BASENAME@-f2pywrappers.f'],
 )
 

From 0fc215c07b8ae59f6e483c3323f186c34b5eb9ac Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Wed, 26 Mar 2025 10:05:31 +0000
Subject: [PATCH 09/22] MAINT: interpolate: link the __fitpack C extension to
 64-bit LAPACK

---
 scipy/interpolate/meson.build | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scipy/interpolate/meson.build b/scipy/interpolate/meson.build
index a4cc26aa9dbe..a62c4480382e 100644
--- a/scipy/interpolate/meson.build
+++ b/scipy/interpolate/meson.build
@@ -128,7 +128,7 @@ py3.extension_module('_rgi_cython',
 
 __fitpack_lib = static_library('__fitpack',
     ['src/__fitpack.h', 'src/__fitpack.cc'],
-    dependencies:[lapack, np_dep, py3_dep],
+    dependencies:[lapack_ilp64, np_dep, py3_dep],
 )
 
 __fitpack_dep = declare_dependency(
@@ -139,7 +139,7 @@ py3.extension_module('_bspl',
   cython_gen_cpp.process('_bspl.pyx'),
   cpp_args: cython_cpp_args,
   include_directories: 'src/',
-  dependencies: [lapack, np_dep, __fitpack_dep],
+  dependencies: [np_dep, __fitpack_dep],
   link_args: version_link_args,
   install: true,
   subdir: 'scipy/interpolate'

From 0d34ecd2d0e854305dfd29f9ff6d835add344b6c Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Thu, 13 Mar 2025 13:51:51 +0100
Subject: [PATCH 10/22] BUG: spatial: Qhull does not need linking to LAPACK

`qhull.pyx` uses cython_lapack, so linking is done at the build time.
NB: and if anything, Qhull might not be 64-bit int ready, so it'll
probably need an LP64 LAPACK.
---
 scipy/spatial/meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scipy/spatial/meson.build b/scipy/spatial/meson.build
index b37f9d0015d3..1f46d1c7c53d 100644
--- a/scipy/spatial/meson.build
+++ b/scipy/spatial/meson.build
@@ -40,7 +40,7 @@ py3.extension_module('_qhull',
     'qhull_src/src'
   ],
   link_args: version_link_args,
-  dependencies: [lapack_ilp64, np_dep],
+  dependencies: [np_dep],
   install: true,
   subdir: 'scipy/spatial'
 )

From 4bfc3a50bd63d2a9fd598e0bd2088a8d52a252e9 Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Thu, 13 Mar 2025 14:34:56 +0100
Subject: [PATCH 11/22] TST: linalg: bump test tolerances

Violations observed on linux with MKL in the ILP64 mode.
---
 scipy/linalg/tests/test_batch.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/scipy/linalg/tests/test_batch.py b/scipy/linalg/tests/test_batch.py
index 7a32e7a5cd66..7871a31ffa1f 100644
--- a/scipy/linalg/tests/test_batch.py
+++ b/scipy/linalg/tests/test_batch.py
@@ -441,8 +441,8 @@ def test_solve(self, bdim, dtype):
         if len(bdim) == 1:
             x = x[..., np.newaxis]
             b = b[..., np.newaxis]
-        assert_allclose(A @ x - b, 0, atol=1.5e-6)
-        assert_allclose(x, np.linalg.solve(A, b), atol=2e-6)
+        assert_allclose(A @ x - b, 0, atol=2e-6)
+        assert_allclose(x, np.linalg.solve(A, b), atol=3e-6)
 
     @pytest.mark.parametrize('bdim', [(5,), (5, 4), (2, 3, 5, 4)])
     @pytest.mark.parametrize('dtype', floating)
@@ -455,8 +455,8 @@ def test_lu_solve(self, bdim, dtype):
         if len(bdim) == 1:
             x = x[..., np.newaxis]
             b = b[..., np.newaxis]
-        assert_allclose(A @ x - b, 0, atol=1.5e-6)
-        assert_allclose(x, np.linalg.solve(A, b), atol=2e-6)
+        assert_allclose(A @ x - b, 0, atol=2e-6)
+        assert_allclose(x, np.linalg.solve(A, b), atol=3e-6)
 
     @pytest.mark.parametrize('l_and_u', [(1, 1), ([2, 1, 0], [0, 1 , 2])])
     @pytest.mark.parametrize('bdim', [(5,), (5, 4), (2, 3, 5, 4)])

From 3f9548bb454d55e152bb9607600fa4058b05caa4 Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Thu, 13 Mar 2025 17:01:59 +0100
Subject: [PATCH 12/22] ENH: integrate: make lsoda.pyf and vode.pyf int64-aware

---
 scipy/integrate/lsoda.pyf | 11 ++++++++++-
 scipy/integrate/vode.pyf  | 11 +++++++++--
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/scipy/integrate/lsoda.pyf b/scipy/integrate/lsoda.pyf
index d09e32a59184..20cc688320f5 100644
--- a/scipy/integrate/lsoda.pyf
+++ b/scipy/integrate/lsoda.pyf
@@ -23,11 +23,20 @@ python module lsoda__user__routines
 end python module lsoda__user__routines
 
 python module _lsoda
+  usercode '''
+
+#ifdef HAVE_BLAS_ILP64
+typedef npy_int64 F_INT;
+#else
+typedef int F_INT;
+#endif
+'''
+
     interface
        subroutine lsoda(f,neq,y,t,tout,itol,rtol,atol,itask,istate,iopt,rwork,lrw,iwork,liw,jac,jt)
          ! y1,t,istate = lsoda(f,jac,y0,t0,t1,rtol,atol,itask,istate,rwork,iwork,mf)
          callstatement (*f2py_func)(cb_f_in_lsoda__user__routines,&neq,y,&t,&tout,&itol,rtol,atol,&itask,&istate,&iopt,rwork,&lrw,iwork,&liw,cb_jac_in_lsoda__user__routines,&jt)
-         callprotoargument void*,int*,double*,double*,double*,int*,double*,double*,int*,int*,int*,double*,int*,int*,int*,void*,int*
+         callprotoargument void*,F_INT*,double*,double*,double*,F_INT*,double*,double*,F_INT*,F_INT*,F_INT*,double*,F_INT*,F_INT*,F_INT*,void*,F_INT*
          use lsoda__user__routines
          external f
          external jac
diff --git a/scipy/integrate/vode.pyf b/scipy/integrate/vode.pyf
index 90774653486f..94181009d268 100644
--- a/scipy/integrate/vode.pyf
+++ b/scipy/integrate/vode.pyf
@@ -50,11 +50,18 @@ python module zvode__user__routines
 end python module zvode__user__routines
 
 python module _vode
+  usercode '''
+#ifdef HAVE_BLAS_ILP64
+typedef npy_int64 F_INT;
+#else
+typedef int F_INT;
+#endif
+'''
     interface
        subroutine dvode(f,jac,neq,y,t,tout,itol,rtol,atol,itask,istate,iopt,rwork,lrw,iwork,liw,mf,rpar,ipar)
          ! y1,t,istate = dvode(f,jac,y0,t0,t1,rtol,atol,itask,istate,rwork,iwork,mf)
          callstatement (*f2py_func)(cb_f_in_dvode__user__routines,&neq,y,&t,&tout,&itol,rtol,atol,&itask,&istate,&iopt,rwork,&lrw,iwork,&liw,cb_jac_in_dvode__user__routines,&mf,&rpar,&ipar)
-         callprotoargument void*,int*,double*,double*,double*,int*,double*,double*,int*,int*,int*,double*,int*,int*,int*,void*,int*,double*,int*
+         callprotoargument void*,F_INT*,double*,double*,double*,F_INT*,double*,double*,F_INT*,F_INT*,F_INT*,double*,F_INT*,F_INT*,F_INT*,void*,F_INT*,double*,F_INT*
          use dvode__user__routines
          external f
          external jac
@@ -85,7 +92,7 @@ python module _vode
        subroutine zvode(f,jac,neq,y,t,tout,itol,rtol,atol,itask,istate,iopt,zwork,lzw,rwork,lrw,iwork,liw,mf,rpar,ipar)
          ! y1,t,istate = zvode(f,jac,y0,t0,t1,rtol,atol,itask,istate,rwork,iwork,mf)
          callstatement (*f2py_func)(cb_f_in_zvode__user__routines,&neq,y,&t,&tout,&itol,rtol,atol,&itask,&istate,&iopt,zwork,&lzw,rwork,&lrw,iwork,&liw,cb_jac_in_zvode__user__routines,&mf,&rpar,&ipar)
-         callprotoargument void*,int*,complex_double*,double*,double*,int*,double*,double*,int*,int*,int*,complex_double*,int*,double*,int*,int*,int*,void*,int*,double*,int*
+         callprotoargument void*,F_INT*,complex_double*,double*,double*,F_INT*,double*,double*,F_INT*,F_INT*,F_INT*,complex_double*,F_INT*,double*,F_INT*,F_INT*,F_INT*,void*,F_INT*,double*,F_INT*
          use zvode__user__routines
          external f
          external jac

From ffdd57dbc0e9ac37d1751b1e866817a1eb9af50e Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Thu, 13 Mar 2025 17:11:31 +0100
Subject: [PATCH 13/22] BLD: integrate: add int64 flags to ODE wrappers (lsoda,
 dop, vode, zvode)

---
 scipy/integrate/_ode.py     |  1 -
 scipy/integrate/meson.build | 64 +++++++++++++++++++++++++++++--------
 2 files changed, 50 insertions(+), 15 deletions(-)

diff --git a/scipy/integrate/_ode.py b/scipy/integrate/_ode.py
index 1c1fff502c48..ed81ad16b27b 100644
--- a/scipy/integrate/_ode.py
+++ b/scipy/integrate/_ode.py
@@ -95,7 +95,6 @@ class complex_ode
 _vode_int_dtype = _vode.types.intvar.dtype
 _lsoda_int_dtype = _lsoda.types.intvar.dtype
 
-
 # lsoda, vode and zvode are not thread-safe. VODE_LOCK protects both vode and
 # zvode; they share the `def run` implementation
 LSODA_LOCK = threading.Lock()
diff --git a/scipy/integrate/meson.build b/scipy/integrate/meson.build
index e76f864d7956..d35a6de55cae 100644
--- a/scipy/integrate/meson.build
+++ b/scipy/integrate/meson.build
@@ -35,43 +35,58 @@ quadpack_test_src = [
   'tests/_test_multivariate.c'
 ]
 
+
+if use_ilp64
+  _fflag_intsize = _fflag_ilp64
+else
+  _fflag_intsize = _fflag_lp64
+endif
+
+
 mach_lib = static_library('mach_lib',
   mach_src,
   gnu_symbol_visibility: 'hidden',
-  fortran_args: [fortran_ignore_warnings, _fflag_ilp64],
+  fortran_args: [fortran_ignore_warnings, _fflag_intsize],
 )
 
 
 lsoda_lib = static_library('lsoda_lib',
   lsoda_src,
-  fortran_args: [fortran_ignore_warnings, _fflag_ilp64],
+  fortran_args: [fortran_ignore_warnings, _fflag_intsize],
   override_options: ['b_lto=false'],
   gnu_symbol_visibility: 'hidden',
 )
 
 vode_lib = static_library('vode_lib',
   vode_src,
-  fortran_args: [fortran_ignore_warnings, _fflag_ilp64],
+  fortran_args: [fortran_ignore_warnings, _fflag_intsize],
   override_options: ['b_lto=false'],
   gnu_symbol_visibility: 'hidden',
 )
 
 dop_lib = static_library('dop_lib',
   dop_src,
-  fortran_args: [fortran_ignore_warnings, _fflag_ilp64],
+  fortran_args: [fortran_ignore_warnings, _fflag_intsize],
   gnu_symbol_visibility: 'hidden',
 )
 
 py3.extension_module('_quadpack',
   ['__quadpack.h', '__quadpack.c'],
-  dependencies: [np_dep, ccallback_dep, lapack_ilp64, ],
+  dependencies: [np_dep, ccallback_dep, lapack_ilp64],
   install: true,
   subdir: 'scipy/integrate'
 )
 
+
+_c_args_lsoda = []
+if use_ilp64
+  _c_args_lsoda += ['-DHAVE_BLAS_ILP64']
+endif
+
 py3.extension_module('_odepack',
   '_odepackmodule.c',
-  fortran_args: fortran_ignore_warnings,
+  fortran_args: [fortran_ignore_warnings, _fflag_intsize],
+  c_args: _c_args_lsoda,
   link_with: [lsoda_lib, mach_lib],
   link_args: version_link_args,
   dependencies: [lapack_ilp64, np_dep],
@@ -80,10 +95,28 @@ py3.extension_module('_odepack',
   subdir: 'scipy/integrate'
 )
 
+
+if use_ilp64
+   # generator only accepts strings, not files
+   f2c_map_file = f2py_ilp64_opts[1]
+   extra_arg = f2py_ilp64_opts[0] + '=' + fs.parent(f2c_map_file) / fs.name(f2c_map_file)
+  _vodemodule_obj = f2py_gen.process('vode.pyf', extra_args: extra_arg)
+  _lsodamodule_obj = f2py_gen.process('lsoda.pyf', extra_args: extra_arg)
+  _dopmodule_obj = f2py_gen.process('dop.pyf', extra_args: extra_arg)
+  _testodeintmodule_obj = f2py_gen.process('tests/test_odeint_banded.pyf', extra_args: extra_arg)
+else
+  _vodemodule_obj = f2py_gen.process('vode.pyf')
+  _lsodamodule_obj = f2py_gen.process('lsoda.pyf')
+  _dopmodule_obj = f2py_gen.process('dop.pyf')
+  _testodeintmodule_obj = f2py_gen.process('tests/test_odeint_banded.pyf')
+endif
+
+
 py3.extension_module('_vode',
-  f2py_gen.process('vode.pyf'),
+  _vodemodule_obj,
   link_with: [vode_lib],
-  c_args: [Wno_unused_variable],
+  fortran_args: [_fflag_intsize],
+  c_args: [Wno_unused_variable] + _c_args_lsoda,
   link_args: version_link_args,
   dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep],
   install: true,
@@ -92,9 +125,10 @@ py3.extension_module('_vode',
 )
 
 py3.extension_module('_lsoda',
-  f2py_gen.process('lsoda.pyf'),
+  _lsodamodule_obj,
   link_with: [lsoda_lib, mach_lib],
-  c_args: [Wno_unused_variable],
+  fortran_args: [_fflag_intsize],
+  c_args: [Wno_unused_variable] + _c_args_lsoda,
   dependencies: [lapack_ilp64, fortranobject_dep],
   link_args: version_link_args,
   install: true,
@@ -103,9 +137,10 @@ py3.extension_module('_lsoda',
 )
 
 py3.extension_module('_dop',
-  f2py_gen.process('dop.pyf'),
+  _dopmodule_obj,
   link_with: [dop_lib],
-  c_args: [Wno_unused_variable],
+  fortran_args: [_fflag_intsize],
+  c_args: [Wno_unused_variable] + _c_args_lsoda,
   dependencies: [fortranobject_dep],
   link_args: version_link_args,
   install: true,
@@ -122,9 +157,10 @@ py3.extension_module('_test_multivariate',
 )
 
 py3.extension_module('_test_odeint_banded',
-  ['tests/banded5x5.f', f2py_gen.process('tests/test_odeint_banded.pyf')],
+  ['tests/banded5x5.f', _testodeintmodule_obj],
   link_with: [lsoda_lib, mach_lib],
-  fortran_args: _fflag_Wno_unused_dummy_argument,
+  fortran_args: [_fflag_intsize, _fflag_Wno_unused_dummy_argument],
+  c_args: _c_args_lsoda,
   link_args: version_link_args,
   dependencies: [lapack_ilp64, fortranobject_dep],
   install: true,

From 4f0089082ca84905e3e9150f93b0507db3bde7c9 Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Thu, 13 Mar 2025 19:47:35 +0100
Subject: [PATCH 14/22] BLD: sparse/arpack: add an int64 flag

---
 scipy/sparse/linalg/_eigen/arpack/meson.build | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scipy/sparse/linalg/_eigen/arpack/meson.build b/scipy/sparse/linalg/_eigen/arpack/meson.build
index 876b19bbb8c5..edb77bc4430e 100644
--- a/scipy/sparse/linalg/_eigen/arpack/meson.build
+++ b/scipy/sparse/linalg/_eigen/arpack/meson.build
@@ -107,6 +107,7 @@ _arpack = py3.extension_module('_arpack',
   link_args: version_link_args,
   dependencies: [lapack_ilp64, blas_ilp64, fortranobject_dep],
   fortran_args: _fflag_ilp64,
+  c_args: ['-DHAVE_BLAS_ILP64'],
   install: true,
   link_language: 'fortran',
   subdir: 'scipy/sparse/linalg/_eigen/arpack'

From 043a40e5787b146260ece50f5692ba9dcd5c6e4d Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Sun, 16 Mar 2025 13:53:37 +0100
Subject: [PATCH 15/22] BLD: special: link to LP64-bit LAPACK, use
 cython_special in ellip_harm

---
 scipy/special/_ellip_harm.pxd | 3 ++-
 scipy/special/meson.build     | 4 ++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/scipy/special/_ellip_harm.pxd b/scipy/special/_ellip_harm.pxd
index 42f8ae366e8b..53f883e9860e 100644
--- a/scipy/special/_ellip_harm.pxd
+++ b/scipy/special/_ellip_harm.pxd
@@ -34,6 +34,7 @@ from . cimport sf_error
 
 from libc.math cimport sqrt, fabs, pow, NAN
 from libc.stdlib cimport malloc, free
+from scipy.linalg.cython_lapack cimport dstevr
 
 cdef extern from "lapack_defs.h":
     ctypedef int CBLAS_INT  # actual type defined in the header
@@ -162,7 +163,7 @@ cdef inline double* lame_coefficients(double h2, double k2, int n, int p,
     for i in range(0, size-1):
         dd[i] = g[i]*ss[i]/ss[i+1]
 
-    c_dstevr("V", "I", &size, d, dd, &vl, &vu, &tp, &tp, &tol, &c, w, eigv,
+    dstevr("V", "I", &size, d, dd, &vl, &vu, &tp, &tp, &tol, &c, w, eigv,
              &size, isuppz, work, &lwork, iwork, &liwork, &info)
 
     if info != 0:
diff --git a/scipy/special/meson.build b/scipy/special/meson.build
index d00d44583566..029f932151bb 100644
--- a/scipy/special/meson.build
+++ b/scipy/special/meson.build
@@ -123,7 +123,7 @@ py3.extension_module('_ufuncs',
   cpp_args: ['-DSP_SPECFUN_ERROR'],
   include_directories: ['../_lib', '../_build_utils/src'],
   dependencies: [
-    lapack_ilp64,
+    lapack_dep,
     npymath_lib,
     np_dep,
   ],
@@ -193,7 +193,7 @@ py3.extension_module('cython_special',
   cpp_args: ['-DSP_SPECFUN_ERROR'],
   include_directories: ['../_lib', '../_build_utils/src'],
   link_args: version_link_args,
-  dependencies: [np_dep, npymath_lib, lapack_dep],
+  dependencies: [np_dep, npymath_lib, sf_error_state_dep, lapack_dep],
   link_with: cdflib_lib,
   install: true,
   subdir: 'scipy/special',

From 8b60d82fee4dc06e3acd500e81bd8eb9bb220a8f Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Sun, 16 Mar 2025 14:16:49 +0100
Subject: [PATCH 16/22] MAINT: special: no need to link to LAPACK explicitly
 with cython_lapack

---
 scipy/special/_ellip_harm.pxd |  7 +------
 scipy/special/lapack_defs.h   | 20 --------------------
 scipy/special/meson.build     |  4 ++--
 3 files changed, 3 insertions(+), 28 deletions(-)
 delete mode 100644 scipy/special/lapack_defs.h

diff --git a/scipy/special/_ellip_harm.pxd b/scipy/special/_ellip_harm.pxd
index 53f883e9860e..939ed1cd50e1 100644
--- a/scipy/special/_ellip_harm.pxd
+++ b/scipy/special/_ellip_harm.pxd
@@ -36,13 +36,8 @@ from libc.math cimport sqrt, fabs, pow, NAN
 from libc.stdlib cimport malloc, free
 from scipy.linalg.cython_lapack cimport dstevr
 
-cdef extern from "lapack_defs.h":
+cdef extern from "npy_cblas.h":
     ctypedef int CBLAS_INT  # actual type defined in the header
-    void c_dstevr(char *jobz, char *range, CBLAS_INT *n, double *d, double *e,
-                  double *vl, double *vu, CBLAS_INT *il, CBLAS_INT *iu, double *abstol,
-                  CBLAS_INT *m, double *w, double *z, CBLAS_INT *ldz, CBLAS_INT *isuppz,
-                  double *work, CBLAS_INT *lwork, CBLAS_INT *iwork, CBLAS_INT *liwork,
-                  CBLAS_INT *info) nogil
 
 
 @cython.wraparound(False)
diff --git a/scipy/special/lapack_defs.h b/scipy/special/lapack_defs.h
deleted file mode 100644
index 0d20ba1ca619..000000000000
--- a/scipy/special/lapack_defs.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Handle different Fortran conventions.
- */
-
-#include "npy_cblas.h"
-
-extern void BLAS_FUNC(dstevr)(char *jobz, char *range, CBLAS_INT *n, double *d, double *e,
-                              double *vl, double *vu, CBLAS_INT *il, CBLAS_INT *iu, double *abstol,
-                              CBLAS_INT *m, double *w, double *z, CBLAS_INT *ldz, CBLAS_INT *isuppz,
-                              double *work, CBLAS_INT *lwork, CBLAS_INT *iwork, CBLAS_INT *liwork,
-                              CBLAS_INT *info, size_t jobz_len, size_t range_len);
-
-static void c_dstevr(char *jobz, char *range, CBLAS_INT *n, double *d, double *e,
-                     double *vl, double *vu, CBLAS_INT *il, CBLAS_INT *iu, double *abstol,
-                     CBLAS_INT *m, double *w, double *z, CBLAS_INT *ldz, CBLAS_INT *isuppz,
-                     double *work, CBLAS_INT *lwork, CBLAS_INT *iwork, CBLAS_INT *liwork, CBLAS_INT *info) {
-    BLAS_FUNC(dstevr)(jobz, range, n, d, e, vl, vu, il, iu, abstol, m,
-                      w, z, ldz, isuppz, work, lwork, iwork, liwork, info,
-                      1, 1);
-}
diff --git a/scipy/special/meson.build b/scipy/special/meson.build
index 029f932151bb..b47fcd5684e6 100644
--- a/scipy/special/meson.build
+++ b/scipy/special/meson.build
@@ -176,7 +176,7 @@ py3.extension_module('_ellip_harm_2',
   cpp_args: ['-DSP_SPECFUN_ERROR'],
   include_directories: ['../_lib', '../_build_utils/src'],
   link_args: version_link_args,
-  dependencies: [lapack_dep, np_dep],
+  dependencies: [np_dep],
   install: true,
   subdir: 'scipy/special',
 )
@@ -193,7 +193,7 @@ py3.extension_module('cython_special',
   cpp_args: ['-DSP_SPECFUN_ERROR'],
   include_directories: ['../_lib', '../_build_utils/src'],
   link_args: version_link_args,
-  dependencies: [np_dep, npymath_lib, sf_error_state_dep, lapack_dep],
+  dependencies: [np_dep, npymath_lib, lapack_dep],
   link_with: cdflib_lib,
   install: true,
   subdir: 'scipy/special',

From a1e5a44f902ed8c7e2971d329a7673c70994ba1a Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Wed, 26 Mar 2025 09:42:13 +0000
Subject: [PATCH 17/22] BLD: optimize: link lbfgsb to 32-bit LP64 LAPACK

It otherwise segfaults. Needs using BLAS_FUNC maybe?
---
 scipy/optimize/meson.build | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/scipy/optimize/meson.build b/scipy/optimize/meson.build
index 5247e5f1c5e0..5c183582ef76 100644
--- a/scipy/optimize/meson.build
+++ b/scipy/optimize/meson.build
@@ -62,12 +62,14 @@ py3.extension_module('_zeros',
   subdir: 'scipy/optimize'
 )
 
+
+# TODO: link to ILP64 LAPACK
 py3.extension_module('_lbfgsb',
   [
     '__lbfgsb.h',
     '__lbfgsb.c',
   ],
-  dependencies: [lapack_ilp64, blas_ilp64, np_dep],
+  dependencies: [lapack_dep, blas_dep, np_dep],
   link_args: version_link_args,
   install: true,
   subdir: 'scipy/optimize'

From 7d70b4e2643a83f1f30edb220169292c3c164a9f Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Sat, 22 Mar 2025 22:12:11 +0100
Subject: [PATCH 18/22] TEMP: debug print in generate_f2pymod

---
 tools/generate_f2pymod.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/generate_f2pymod.py b/tools/generate_f2pymod.py
index aaedad2bd26f..ad5fb5e8de6b 100644
--- a/tools/generate_f2pymod.py
+++ b/tools/generate_f2pymod.py
@@ -298,6 +298,9 @@ def main():
         if args.f2cmap:
             cmd += ['--f2cmap', args.f2cmap]
 
+        print("!!! CMD =", cmd, " at ", os.getcwd())
+
+
         p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                              stderr=subprocess.PIPE, cwd=os.getcwd())
         out, err = p.communicate()

From a29dc67233137a5cc3525afa2a84f46a6de63b10 Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Sat, 22 Mar 2025 22:14:49 +0100
Subject: [PATCH 19/22] BLD: fix up MKL ILP64 detection

---
 scipy/meson.build | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/scipy/meson.build b/scipy/meson.build
index 8c2e457ca37c..cf9d09f00298 100644
--- a/scipy/meson.build
+++ b/scipy/meson.build
@@ -302,7 +302,7 @@ if blas_name == 'auto'
     endif
   endforeach
 else
-  if blas_name == 'mkl'
+  if uses_mkl
     mkl_uses_sdl = false
     blas = dependency('mkl',
       modules: blas_interface + mkl_opts,
@@ -406,6 +406,7 @@ dependency_map = {
   'PYBIND11': pybind11_dep,
 }
 
+# NB: from this point on blas_name is e.g. 'mkl-lp64-dynamic-seq'
 blas_name = blas.name()
 lapack_name = lapack.name()
 uses_mkl = blas_name.to_lower().startswith('mkl')
@@ -446,11 +447,12 @@ if use_ilp64
   endif
 
   # Run the detection
-  if blas_name == 'mkl'
+  if uses_mkl
+    mkl_uses_sdl = false   # FIXME, why
     if mkl_uses_sdl
       mkl_opts = ['sdl: true']
     endif
-    blas_ilp64 = dependency('mkl', modules: [blas_interface, mkl_opts])
+    blas_ilp64 = dependency('mkl', modules: ['interface: ilp64'] + mkl_opts)
     lapack_ilp64 = blas_ilp64
   else
     if blas_name == 'openblas'
@@ -478,6 +480,8 @@ if use_ilp64
     _blas_incdir = ['.']
   endif
   # Declare the ILP64 dependencies
+  message('BLAS / LAPACK ILP64 detected: ', blas_ilp64.name(), ', ', lapack_ilp64.name())
+
   blas_ilp64 = declare_dependency(
     dependencies: [blas_ilp64],
     compile_args: _args_blas,
@@ -485,8 +489,11 @@ if use_ilp64
   )
   lapack_ilp64 = declare_dependency(dependencies: [lapack_ilp64, blas_ilp64])
 else
+  # we're not using ILP64; user will link to the always-available LP64 blas/lapack
+  # (all users must use preprocessor macros BLAS_NAME to handle the two options)
   blas_ilp64 = blas
   lapack_ilp64 = lapack
+  message('LAPACK ILP64 not requested / not detected.')
 endif
 
 # End of BLAS/LAPACK handling

From 48a011e703a09c8cba55b65089128abfdf039c42 Mon Sep 17 00:00:00 2001
From: Ralf Gommers <ralf.gommers@gmail.com>
Date: Wed, 26 Mar 2025 13:56:43 +0100
Subject: [PATCH 20/22] CI: separate the MKL ILP64 job

---
 .github/workflows/linux_mkl_ilp64.yml | 88 +++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 .github/workflows/linux_mkl_ilp64.yml

diff --git a/.github/workflows/linux_mkl_ilp64.yml b/.github/workflows/linux_mkl_ilp64.yml
new file mode 100644
index 000000000000..d7bf0b7d7f2e
--- /dev/null
+++ b/.github/workflows/linux_mkl_ilp64.yml
@@ -0,0 +1,88 @@
+name: BLAS tests (Linux)
+
+# This file is meant for testing different BLAS/LAPACK flavors and build
+# options on Linux. All other yml files for Linux will only test without BLAS
+# (mostly because that's easier and faster to build) or with the same 64-bit
+# OpenBLAS build that is used in the wheel jobs.
+#
+# Jobs and their purpose:
+#
+#   - mkl:
+#         Tests MKL installed from PyPI (because easiest/fastest, if broken) in
+#         3 ways: both LP64 and ILP64 via pkg-config, and then using the
+#         Single Dynamic Library (SDL, or `libmkl_rt`).
+
+
+on:
+  pull_request:
+    branches:
+      - main
+      - maintenance/**
+
+defaults:
+  run:
+    shell: bash
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read # to fetch code (actions/checkout)
+
+jobs:
+
+  mkl:
+    if: "github.repository == 'rgommers/scipy'"
+    runs-on: ubuntu-latest
+    name: "MKL (LP64 split, SDL)"
+    steps:
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      with:
+        submodules: recursive
+        fetch-depth: 0
+    - uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c # v5.0.0
+      with:
+        python-version: '3.11'
+
+    - name: Install dependencies
+      run: |
+        pip install -r requirements/all.txt
+        pip install git+https://github.com/numpy/meson.git@main-numpymeson
+        pip install "mkl==2023.2.0" "mkl-devel==2023.2.0"
+
+    - name: Repair MKL pkg-config files and symlinks
+      run: |
+        # MKL 2023.2 works when installed from conda-forge (except for `-iomp`
+        # and `-tbb` pkg-config files), Spack, or with the standalone Intel
+        # installer. The standalone installer is the worst option, since it's
+        # large and clumsy to install and requires running a setvars.sh script
+        # before things work. The PyPI MKL packages are broken and need the
+        # fixes in this step. For details, see
+        # https://github.com/conda-forge/intel_repack-feedstock/issues/34
+        cd $Python3_ROOT_DIR/lib/pkgconfig
+        sed -i 's/\/intel64//g' mkl*.pc
+        # add the expected .so -> .so.2 symlinks to fix linking
+        cd ..
+        for i in $( ls libmkl*.so.2 ); do ln -s $i ${i%.*}; done
+
+    - name: Build with defaults (LP64)
+      run: |
+        pkg-config --libs mkl-dynamic-lp64-seq  # check link flags
+        python dev.py build
+
+    - name: Test
+      run: python dev.py test
+
+    - name: Build without pkg-config (default options, SDL)
+      run: |
+        git clean -xdf > /dev/null
+        pushd $Python3_ROOT_DIR/lib/pkgconfig
+        rm mkl*.pc
+        popd
+        export MKLROOT=$Python3_ROOT_DIR
+        python dev.py build
+
+    - name: Test
+      run: python dev.py test
+

From 6011499405e7020ea7d4abdfd994782b1b9b6da9 Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Wed, 26 Mar 2025 13:59:19 +0100
Subject: [PATCH 21/22] CI: tweak the ILP64 job

---
 .github/workflows/linux_mkl_ilp64.yml | 58 ++++++++++++++++++---------
 1 file changed, 38 insertions(+), 20 deletions(-)

diff --git a/.github/workflows/linux_mkl_ilp64.yml b/.github/workflows/linux_mkl_ilp64.yml
index d7bf0b7d7f2e..0be2e2ba0735 100644
--- a/.github/workflows/linux_mkl_ilp64.yml
+++ b/.github/workflows/linux_mkl_ilp64.yml
@@ -32,8 +32,7 @@ permissions:
 
 jobs:
 
-  mkl:
-    if: "github.repository == 'rgommers/scipy'"
+  mkl-lp64:
     runs-on: ubuntu-latest
     name: "MKL (LP64 split, SDL)"
     steps:
@@ -47,24 +46,12 @@ jobs:
 
     - name: Install dependencies
       run: |
-        pip install -r requirements/all.txt
+        sudo apt-get update
+        sudo apt-get install -y gfortran
+        pip install cython numpy pybind11 pythran pytest hypothesis pytest-xdist pooch
+        pip install -r requirements/dev.txt
         pip install git+https://github.com/numpy/meson.git@main-numpymeson
-        pip install "mkl==2023.2.0" "mkl-devel==2023.2.0"
-
-    - name: Repair MKL pkg-config files and symlinks
-      run: |
-        # MKL 2023.2 works when installed from conda-forge (except for `-iomp`
-        # and `-tbb` pkg-config files), Spack, or with the standalone Intel
-        # installer. The standalone installer is the worst option, since it's
-        # large and clumsy to install and requires running a setvars.sh script
-        # before things work. The PyPI MKL packages are broken and need the
-        # fixes in this step. For details, see
-        # https://github.com/conda-forge/intel_repack-feedstock/issues/34
-        cd $Python3_ROOT_DIR/lib/pkgconfig
-        sed -i 's/\/intel64//g' mkl*.pc
-        # add the expected .so -> .so.2 symlinks to fix linking
-        cd ..
-        for i in $( ls libmkl*.so.2 ); do ln -s $i ${i%.*}; done
+        pip install mkl mkl-devel
 
     - name: Build with defaults (LP64)
       run: |
@@ -84,5 +71,36 @@ jobs:
         python dev.py build
 
     - name: Test
-      run: python dev.py test
+      run: python dev.py test -j 2
+
+
+  mkl-ilp64:
+    runs-on: ubuntu-latest
+    name: "MKL ILP64"
+    steps:
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      with:
+        submodules: recursive
+        fetch-depth: 0
+    - uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c # v5.0.0
+      with:
+        python-version: '3.11'
+
+    - name: Install dependencies
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y gfortran
+        pip install cython numpy pybind11 pythran pytest hypothesis pytest-xdist pooch
+        pip install -r requirements/dev.txt
+        pip install git+https://github.com/numpy/meson.git@main-numpymeson
+        pip install mkl mkl-devel
+
+    - name: Build with ILP64
+      run: |
+        pkg-config --libs mkl-dynamic-ilp64-seq  # check link flags
+        python dev.py build -C-Dblas-order=mkl -C-Duse-ilp64=true
+
+    - name: Test
+      run: python dev.py test -j 2
+
 

From 20e49f0daf02238bb4587cba83b0663261e1449d Mon Sep 17 00:00:00 2001
From: Evgeni Burovski <evgeny.burovskiy@gmail.com>
Date: Wed, 26 Mar 2025 15:38:53 +0100
Subject: [PATCH 22/22] TEMP: run CI on the fork

---
 .github/workflows/linux_mkl_ilp64.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/workflows/linux_mkl_ilp64.yml b/.github/workflows/linux_mkl_ilp64.yml
index 0be2e2ba0735..bf35aaaf1e6e 100644
--- a/.github/workflows/linux_mkl_ilp64.yml
+++ b/.github/workflows/linux_mkl_ilp64.yml
@@ -33,6 +33,7 @@ permissions:
 jobs:
 
   mkl-lp64:
+    if: "github.repository == 'ev-br/scipy'"
     runs-on: ubuntu-latest
     name: "MKL (LP64 split, SDL)"
     steps:
@@ -75,6 +76,7 @@ jobs:
 
 
   mkl-ilp64:
+    if: "github.repository == 'ev-br/scipy'"
     runs-on: ubuntu-latest
     name: "MKL ILP64"
     steps: