Adding support to control mpi use in meson.

Disabling mpi in macos brew build (bug in the MPI lib).

.github/workflows/build_check.yml

@@ -78,15 +78,15 @@ jobs:
         python-version: '3.x' 
     - name: Brew install pre-requisites
       run: |
-        brew install gobject-introspection gsl gmp mpfr fftw cfitsio libfyaml nlopt gfortran gtk-doc glib openblas open-mpi
+        brew install gobject-introspection gsl gmp mpfr fftw cfitsio libfyaml nlopt gfortran gtk-doc glib openblas
     - name: Pip install pre-requisites
       run: |
         pip3 install meson ninja pytest pytest-tap numpy pygobject
     - name: Ensure clear Jupyter Notebooks
       uses: ResearchSoftwareActions/EnsureCleanNotebooksAction@1.1
     - name: Configure NumCosmo
       run: | 
-        meson setup build -Dbuildtype=release -Dnumcosmo_py=true --prefix=/usr || (cat build/meson-logs/meson-log.txt && exit 1)
+        meson setup build -Dbuildtype=release -Dnumcosmo_py=true -Dmpi=disabled --prefix=/usr || (cat build/meson-logs/meson-log.txt && exit 1)
     - name: Building NumCosmo
       run: |
         meson compile -C build

meson.build

@@ -360,26 +360,39 @@ flint_req = '>= 3.0'
 #######################################################################################
 message('Checking for MPI')
 
-mpi_c_dep = dependency(
-  'mpi',
-  language: 'c',
-  required: false,
-)
+if get_option('mpi').auto() or get_option('mpi').enabled()
 
-mpi_fortran_dep = dependency(
-  'mpi',
-  language: 'fortran',
-  required: false,
-)
+  mpi_c_dep = dependency(
+    'mpi',
+    language: 'c',
+    required: false,
+  )
 
-# MPICH is not found by the mpi dependency, so we need to check for it manually
-if not mpi_c_dep.found()
-  mpi_c_dep = dependency('mpich', required: false)
-endif
+  mpi_fortran_dep = dependency(
+    'mpi',
+    language: 'fortran',
+    required: false,
+  )
 
-# MPICH is not found by the mpi dependency, so we need to check for it manually
-if not mpi_fortran_dep.found()
-  mpi_fortran_dep = dependency('mpichf90', required: false)
+  # MPICH is not found by the mpi dependency, so we need to check for it manually
+  if (not mpi_c_dep.found())
+    mpi_c_dep = dependency('mpich', required: false)
+  endif
+
+  # MPICH is not found by the mpi dependency, so we need to check for it manually
+  if (not mpi_fortran_dep.found())
+    mpi_fortran_dep = dependency('mpichf90', required: false)
+  endif
+
+  if get_option('mpi').enabled() and not mpi_c_dep.found()
+    error(
+      '''MPI support requested but not found. Both attempts to locate MPI dependency, \
+      using Meson's generic finder and MPICH specifically, failed.''',
+    )
+  endif
+else
+  mpi_c_dep = not_found
+  mpi_fortran_dep = not_found
 endif
 
 if mpi_c_dep.found()

meson_options.txt

@@ -131,3 +131,10 @@ option(
        value: false,
        description: 'Enable MPI debug messages',
 )
+
+option(
+       'mpi',
+       type: 'feature',
+       value: 'auto',
+       description: 'Enable MPI support',
+)