add almxfl test

Author: zonca

python/libsharp/tests/test_smoothing_noise_pol_mpi.py

@@ -0,0 +1,137 @@
+# This test needs to be run with:
+
+# mpirun -np X python test_smoothing_noise_pol_mpi.py
+
+from mpi4py import MPI
+
+import numpy as np
+
+import healpy as hp
+
+import libsharp
+
+mpi = True
+rank = MPI.COMM_WORLD.Get_rank()
+
+nside = 256
+npix = hp.nside2npix(nside)
+
+np.random.seed(100)
+input_map = np.random.normal(size=(3, npix))
+fwhm_deg = 10
+lmax = 512
+
+nrings = 4 * nside - 1  # four missing pixels
+
+if rank == 0:
+    print("total rings", nrings)
+
+n_mpi_processes = MPI.COMM_WORLD.Get_size()
+rings_per_process = nrings // n_mpi_processes + 1
+# ring indices are 1-based
+
+ring_indices_emisphere = np.arange(2*nside, dtype=np.int32) + 1
+local_ring_indices = ring_indices_emisphere[rank::n_mpi_processes]
+
+# to improve performance, simmetric rings north/south need to be in the same rank
+# therefore we use symmetry to create the full ring indexing
+
+if local_ring_indices[-1] == 2 * nside:
+    # has equator ring
+    local_ring_indices = np.concatenate(
+      [local_ring_indices[:-1],
+       nrings - local_ring_indices[::-1] + 1]
+    )
+else:
+    # does not have equator ring
+    local_ring_indices = np.concatenate(
+      [local_ring_indices,
+       nrings - local_ring_indices[::-1] + 1]
+    )
+
+print("rank", rank, "n_rings", len(local_ring_indices))
+
+if not mpi:
+    local_ring_indices = None
+grid = libsharp.healpix_grid(nside, rings=local_ring_indices)
+
+# returns start index of the ring and number of pixels
+startpix, ringpix, _, _, _ = hp.ringinfo(nside, local_ring_indices.astype(np.int64))
+
+local_npix = grid.local_size()
+
+def expand_pix(startpix, ringpix, local_npix):
+    """Turn first pixel index and number of pixel in full array of pixels
+
+    to be optimized with cython or numba
+    """
+    local_pix = np.empty(local_npix, dtype=np.int64)
+    i = 0
+    for start, num in zip(startpix, ringpix):
+        local_pix[i:i+num] = np.arange(start, start+num)
+        i += num
+    return local_pix
+
+local_pix = expand_pix(startpix, ringpix, local_npix)
+
+local_map = input_map[:, local_pix]
+
+local_hitmap = np.zeros(npix)
+local_hitmap[local_pix] = 1
+hp.write_map("hitmap_{}.fits".format(rank), local_hitmap, overwrite=True)
+
+print("rank", rank, "npix", npix, "local_npix", local_npix, "local_map len", len(local_map), "unique pix", len(np.unique(local_pix)))
+
+local_m_indices = np.arange(rank, lmax + 1, MPI.COMM_WORLD.Get_size(), dtype=np.int32)
+if not mpi:
+    local_m_indices = None
+
+order = libsharp.packed_real_order(lmax, ms=local_m_indices) 
+local_nl = order.local_size()
+print("rank", rank, "local_nl", local_nl, "mval", order.mval())
+
+mpi_comm = MPI.COMM_WORLD if mpi else None
+
+# map2alm
+# maps in libsharp are 3D, 2nd dimension is IQU, 3rd is pixel
+
+alm_sharp_I = libsharp.analysis(grid, order,
+                                np.ascontiguousarray(local_map[0].reshape((1, 1, -1))),
+                                spin=0, comm=mpi_comm)
+alm_sharp_P = libsharp.analysis(grid, order,
+                                np.ascontiguousarray(local_map[1:].reshape((1, 2, -1))),
+                                spin=2, comm=mpi_comm)
+
+beam = hp.gauss_beam(fwhm=np.radians(fwhm_deg), lmax=lmax, pol=True)
+
+print("Smooth")
+# smooth in place (zonca implemented this function)
+order.almxfl(alm_sharp_I, np.ascontiguousarray(beam[:, 0:1]))
+order.almxfl(alm_sharp_P, np.ascontiguousarray(beam[:, (1, 2)]))
+
+# alm2map
+
+new_local_map_I = libsharp.synthesis(grid, order, alm_sharp_I, spin=0, comm=mpi_comm)
+new_local_map_P = libsharp.synthesis(grid, order, alm_sharp_P, spin=2, comm=mpi_comm)
+
+# Transfer map to first process for writing
+
+local_full_map = np.zeros(input_map.shape, dtype=np.float64)
+local_full_map[0, local_pix] = new_local_map_I
+local_full_map[1:, local_pix] = new_local_map_P
+
+output_map = np.zeros(input_map.shape, dtype=np.float64) if rank == 0 else None
+mpi_comm.Reduce(local_full_map, output_map, root=0, op=MPI.SUM)
+
+if rank == 0:
+    # hp.write_map("sharp_smoothed_map.fits", output_map, overwrite=True)
+    # hp_smoothed = hp.alm2map(hp.map2alm(input_map, lmax=lmax), nside=nside) # transform only
+    hp_smoothed = hp.smoothing(input_map, fwhm=np.radians(fwhm_deg), lmax=lmax)
+    std_diff = (hp_smoothed-output_map).std()
+    print("Std of difference between libsharp and healpy", std_diff)
+    # hp.write_map(
+    #     "healpy_smoothed_map.fits",
+    #     hp_smoothed,
+    #     overwrite=True
+    # )
+    assert std_diff < 1e-5