mpi: use mpi attribute consistently as the default MPI implementations

Use the attribute mpi to provide a system wide default MPI
implementation. The default is openmpi (as before).
This now allows for overriding the MPI implentation by using
the overlay mechanism. Build all packages with mpich instead
of the default openmpi can now be achived like this:
self: super:
 {
   mpi = super.mpich;
 }

All derivations that have been using "mpi ? null" to provide optional
building with MPI have been change in the following way to allow for
optional builds with MPI:
{ ...
, mpi
, useMpi ? false
}

2 files changed, 15 insertions, 29 deletions

diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index bd86fed4cb298..360d963fed87f 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -4975,12 +4975,11 @@ in
   hdf5 = callPackage ../tools/misc/hdf5 {
     gfortran = null;
     szip = null;
-    mpi = null;
   };
 
   hdf5-mpi = appendToName "mpi" (hdf5.override {
     szip = null;
-    mpi = pkgs.openmpi;
+    mpiSupport = true;
   });
 
   hdf5-cpp = appendToName "cpp" (hdf5.override {
@@ -7216,6 +7215,8 @@ in
 
   openmpi = callPackage ../development/libraries/openmpi { };
 
+  mpi = openmpi; # this attribute should used to build MPI applications
+
   ucx = callPackage ../development/libraries/ucx {};
 
   openmodelica = callPackage ../applications/science/misc/openmodelica {
@@ -22092,9 +22093,7 @@ in
 
   fractal = callPackage ../applications/networking/instant-messengers/fractal { };
 
-  freecad = libsForQt5.callPackage ../applications/graphics/freecad {
-    mpi = openmpi;
-  };
+  freecad = libsForQt5.callPackage ../applications/graphics/freecad { };
 
   freemind = callPackage ../applications/misc/freemind {
     jdk = jdk8; # TODO: remove override https://github.com/NixOS/nixpkgs/pull/89731
@@ -22480,7 +22479,7 @@ in
 
   hpcg = callPackage ../tools/misc/hpcg/default.nix { };
 
-  hpl = callPackage ../tools/misc/hpl { mpi = openmpi; };
+  hpl = callPackage ../tools/misc/hpl { };
 
   hpmyroom = libsForQt5.callPackage ../applications/networking/hpmyroom { };
 
@@ -27254,15 +27253,11 @@ in
 
   quantum-espresso = callPackage ../applications/science/chemistry/quantum-espresso { };
 
-  quantum-espresso-mpi = callPackage ../applications/science/chemistry/quantum-espresso {
-     mpi = openmpi;
-  };
+  quantum-espresso-mpi = callPackage ../applications/science/chemistry/quantum-espresso { useMpi = true; };
 
   siesta = callPackage ../applications/science/chemistry/siesta { };
 
-  siesta-mpi = callPackage ../applications/science/chemistry/siesta {
-     mpi = openmpi;
-  };
+  siesta-mpi = callPackage ../applications/science/chemistry/siesta { useMpi = true; };
 
   ### SCIENCE/GEOMETRY
 
@@ -27393,7 +27388,7 @@ in
   };
 
   neuron-mpi = appendToName "mpi" (neuron.override {
-    mpi = pkgs.openmpi;
+    useMpi = true;
   });
 
   neuron-full = neuron-mpi.override { inherit python; };
@@ -27445,7 +27440,7 @@ in
   raxml = callPackage ../applications/science/biology/raxml { };
 
   raxml-mpi = appendToName "mpi" (raxml.override {
-    mpi = true;
+    useMpi = true;
   });
 
   sambamba = callPackage ../applications/science/biology/sambamba { };
@@ -27567,9 +27562,7 @@ in
 
   planarity = callPackage ../development/libraries/science/math/planarity { };
 
-  scalapack = callPackage ../development/libraries/science/math/scalapack {
-    mpi = openmpi;
-  };
+  scalapack = callPackage ../development/libraries/science/math/scalapack { };
 
   rankwidth = callPackage ../development/libraries/science/math/rankwidth { };
 
@@ -27599,9 +27592,7 @@ in
 
   petsc = callPackage ../development/libraries/science/math/petsc { };
 
-  parmetis = callPackage ../development/libraries/science/math/parmetis {
-    mpi = openmpi;
-  };
+  parmetis = callPackage ../development/libraries/science/math/parmetis { };
 
   QuadProgpp = callPackage ../development/libraries/science/math/QuadProgpp { };
 
@@ -27631,17 +27622,13 @@ in
 
   ### SCIENCE/MOLECULAR-DYNAMICS
 
-  dl-poly-classic-mpi = callPackage ../applications/science/molecular-dynamics/dl-poly-classic {
-    mpi = openmpi;
-  };
+  dl-poly-classic-mpi = callPackage ../applications/science/molecular-dynamics/dl-poly-classic { };
 
   lammps = callPackage ../applications/science/molecular-dynamics/lammps {
     fftw = fftw;
   };
 
-  lammps-mpi = lowPrio (lammps.override {
-    mpi = openmpi;
-  });
+  lammps-mpi = lowPrio (lammps.override { withMPI = true; });
 
   gromacs = callPackage ../applications/science/molecular-dynamics/gromacs {
     singlePrec = true;
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 84c11b5cd0f1e..c5c17744266da 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -2184,7 +2184,6 @@ in {
 
   fenics = callPackage ../development/libraries/science/math/fenics {
     inherit (pkgs) pkg-config;
-    mpi = pkgs.openmpi;
     pytest = self.pytest_4;
   };
 
@@ -3486,7 +3485,7 @@ in {
 
   labelbox = callPackage ../development/python-modules/labelbox { };
 
-  lammps-cython = callPackage ../development/python-modules/lammps-cython { mpi = pkgs.openmpi; };
+  lammps-cython = callPackage ../development/python-modules/lammps-cython { mpi = pkgs.mpi; };
 
   langcodes = callPackage ../development/python-modules/langcodes { };
 
@@ -4120,7 +4119,7 @@ in {
 
   mpd = callPackage ../development/python-modules/mpd { };
 
-  mpi4py = callPackage ../development/python-modules/mpi4py { mpi = pkgs.openmpi; };
+  mpi4py = callPackage ../development/python-modules/mpi4py { mpi = pkgs.mpi; };
 
   mplleaflet = callPackage ../development/python-modules/mplleaflet { };