Add --disable-libint option and make possible to build without libint

configure.ac

@@ -73,10 +73,24 @@ AC_ARG_WITH(libint,
              LIBINT_LD_LIBRARY_PATH="`readlink -f $withval`/lib";
              LIBS="${LIBS} -L${LIBINT_LD_LIBRARY_PATH} -lint2"
              BUILD_LIBINT=NO],
-            [BUILD_LIBINT=YES
-             external_ldflags_add "libint/lib/libint2.a"
-             external_cppflags_add "libint/include/"
-             EXTERNAL_DEPENDENCIES="libint ${EXTERNAL_DEPENDENCIES}"])
+            [BUILD_LIBINT=YES])
+
+AC_ARG_ENABLE([libint],
+              [AS_HELP_STRING([--disable-libint],
+                              [Don't enable libint if it is not going to be used])],
+              [DISABLE_LIBINT=yes
+               BUILD_LIBINT=NO],
+              [DISABLE_LIBINT=no
+               AC_DEFINE([HAVE_LIBINT],
+                         [1],
+                         [Wether libint is used])])
+
+# Do this here after --disable-libint has been processed
+if test x$BUILD_LIBINT = xYES; then
+  EXTERNAL_DEPENDENCIES="libint ${EXTERNAL_DEPENDENCIES}"
+  external_ldflags_add "libint/lib/libint2.a"
+  external_cppflags_add "libint/include/"
+fi
 
 dnl EIGEN WITH OPTION
 AC_ARG_WITH(eigen,
@@ -253,17 +267,19 @@ dnl -----------------------------------------------------------------------
 dnl CHECK LIBINT
 dnl -----------------------------------------------------------------------
 AM_CONDITIONAL([WITH_BUILD_LIBINT], [test x${BUILD_LIBINT} = xYES])
+AM_CONDITIONAL([DISABLE_LIBINT], [test x${DISABLE_LIBINT} = xyes])
 LIBINT_MAX_AM=4
 AC_ARG_VAR([LIBINT_MAX_AM],
            [Maximum angular momentum for libint. Default: 4],)
-if test xNO = x${BUILD_LIBINT}; then
+if test xNO = x${BUILD_LIBINT} && test x${DISABLE_LIBINT} = xno; then
   CPPFLAGS="$CPPFLAGS -I${LIBINT_CPATH}"
   #LDFLAGS="$LDFLAGS -L${LIBINT_LD_LIBRARY_PATH} -lint2"
   AC_CHECK_HEADER([libint2.h],
                   [],
                   [AC_MSG_ERROR([no libint2.hpp header found in $CPPFLAGS])])
 fi
 
+
 dnl -----------------------------------------------------------------------
 dnl CHECK EIGEN
 dnl -----------------------------------------------------------------------

docs/manual.org

@@ -1,4 +1,5 @@
 #+macro: sisi4s =SiSi4S=
+#+macro: libint [[https://github.com/evaleev/libint][libint]]
 
 * Introduction
 
@@ -53,9 +54,44 @@ in which case you can test the following
 
 
 
-** TODO Libint
+** Libint
+
+We use the {{{libint}}} library
+for some algorithms such as molecular Hartree-Fock.
+
+Our build system is able to compile the library on itself.
+Notable dependencies of {{{libint}}}
+are =libboost= and =libgmp=.
+
+On systems similar to ubuntu these packages should be available
+under package identifiers similar to
+
+- =libgmp3-dev=
+- =libboost1.71-all-dev=
+
+Please refer to {{{libint}}}'s website
+for further information.
+
+*** Using an already compiled version
+
+If you want to reuse an already compiled verison of {{{libint}}}
+you can give the path to the configure script such as
+
+#+begin_src shell :eval no 
+./configure --with-libint=/absolute/path/to/your/libint
+#+end_src
+
+*** Disabling libint
+
+If you don't want to use [[https://github.com/evaleev/libint][libint]] since it takes
+a long time to build and it requires =libboost=,
+you can disable the algorithms that use it with the
+=configure= flag
+
+#+begin_src shell :eval no 
+./configure --disable-libint
+#+end_src
 
-- =BOOST_ROOT=
 
 ** TODO CTF
 

src/Makefile.am

@@ -101,12 +101,14 @@ sisi4s_SOURCES =                                                 \
 ./algorithms/Nop.cxx                                             \
 ./algorithms/PQRSCoulombIntegralsToVertex.cxx
 
-## FOR LIBINT2
-sisi4s_SOURCES +=                                                  \
+if DISABLE_LIBINT
+else
+sisi4s_SOURCES +=                                                \
 ./algorithms/HartreeFockFromGaussian.cxx                         \
 ./algorithms/OneBodyFromGaussian.cxx                             \
 ./algorithms/NuclearRepulsionEnergy.cxx                          \
 ./algorithms/CoulombIntegralsFromGaussian.cxx
+endif
 
 sisi4s_CPPFLAGS = $(EXTERNAL_CPPFLAGS)
 sisi4s_LDADD = $(EXTERNAL_LDFLAGS)
@@ -116,10 +118,8 @@ sisi4s_LDADD = $(EXTERNAL_LDFLAGS)
 ## ./algorithms/UPerturbativeTriples.cxx                            \
 ## ./algorithms/DoublesAmplitudesFromVertex.cxx                     \
 ## ./algorithms/ComplexTensorSum.cxx                                \
-
 ## ./algorithms/TensorContraction.cxx                               \
 ## ./algorithms/ApproximateParticleHoleCoulombVertex.cxx            \
-
 ## ./algorithms/PerturbativeTriples.cxx                             \
 ## ./algorithms/CoulombVertexDecomposition.cxx                      \
 ## ./algorithms/ParticleHoleCoulombVertexDecomposition.cxx          \