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Author: adit4443ya

src/mpi.f90

@@ -185,6 +185,16 @@ integer(kind=MPI_HANDLE_KIND) function handle_mpi_comm_f2c(comm_f) result(c_comm
         end if
     end function handle_mpi_comm_f2c
 
+    integer(kind=MPI_HANDLE_KIND) function handle_mpi_comm_c2f(comm_c) result(f_comm)
+        use mpi_c_bindings, only: c_mpi_comm_c2f, c_mpi_comm_null
+        integer(kind=mpi_handle_kind), intent(in) :: comm_c
+        if (comm_c == c_mpi_comm_null) then
+            f_comm = MPI_COMM_NULL
+        else
+            f_comm = c_mpi_comm_c2f(comm_c)
+        end if
+    end function handle_mpi_comm_c2f
+
     integer(kind=MPI_HANDLE_KIND) function handle_mpi_info_f2c(info_f) result(c_info)
         use mpi_c_bindings, only: c_mpi_info_f2c, c_mpi_info_null
         integer, intent(in) :: info_f
@@ -396,11 +406,7 @@ subroutine MPI_Comm_create_proc(comm, group, newcomm, ierror)
         c_group = c_mpi_group_f2c(group)
         local_ierr = c_mpi_comm_create(c_comm, c_group, c_newcomm)
 
-        if (c_newcomm == c_mpi_comm_null) then
-            newcomm = MPI_COMM_NULL
-        else
-            newcomm = c_mpi_comm_c2f(c_newcomm)
-        end if
+        newcomm = handle_mpi_comm_c2f(c_newcomm)
 
         if (present(ierror)) then
             ierror = local_ierr

src/mpi_constants.c

@@ -4,24 +4,30 @@ MPI_Status* c_MPI_STATUSES_IGNORE = MPI_STATUSES_IGNORE;
 
 MPI_Info c_MPI_INFO_NULL = MPI_INFO_NULL;
 
-MPI_Comm c_MPI_COMM_WORLD = MPI_COMM_WORLD;
+void* c_MPI_IN_PLACE = MPI_IN_PLACE;
+
+// DataType Declarations
 
 MPI_Datatype c_MPI_DOUBLE = MPI_DOUBLE;
 
 MPI_Datatype c_MPI_FLOAT = MPI_FLOAT;
 
 MPI_Datatype c_MPI_INT = MPI_INT;
 
-void* c_MPI_IN_PLACE = MPI_IN_PLACE;
+MPI_Datatype c_MPI_LOGICAL = MPI_LOGICAL;
+
+MPI_Datatype c_MPI_CHARACTER = MPI_CHARACTER;
+
+MPI_Datatype c_MPI_REAL = MPI_REAL;
+
+// Operation Declarations
 
 MPI_Op c_MPI_SUM = MPI_SUM;
 
 MPI_Op c_MPI_MAX = MPI_MAX;
 
-MPI_Datatype c_MPI_LOGICAL = MPI_LOGICAL;
-
-MPI_Datatype c_MPI_CHARACTER = MPI_CHARACTER;
+// Communicators Declarations
 
-MPI_Datatype c_MPI_REAL = MPI_REAL;
+MPI_Comm c_MPI_COMM_NULL = MPI_COMM_NULL;
 
-MPI_Comm c_MPI_COMM_NULL = MPI_COMM_NULL;
+MPI_Comm c_MPI_COMM_WORLD = MPI_COMM_WORLD;

tests/comm_create_1.f90

@@ -2,7 +2,7 @@ program minimal_mre_range
   use mpi
   implicit none
 
-  integer :: ierr, rank, size
+  integer :: ierr, rank, new_rank, size
   integer :: group_world, group_range, new_comm
   integer, dimension(1,3) :: range   ! 1D array to define a single range
   integer :: i
@@ -28,7 +28,9 @@ program minimal_mre_range
 
   ! Print participation
   if (new_comm /= MPI_COMM_NULL) then
-    print *, 'Rank', rank, 'is in the new communicator.'
+    call MPI_COMM_RANK(new_comm, new_rank, ierr)
+    if (ierr /= MPI_SUCCESS) error stop "MPI_COMM_RANK on new_comm failed"
+    print *, 'Global rank', rank, 'is in new_comm with local rank', new_rank
   else
     print *, 'Rank', rank, 'is NOT in the new communicator.'
   end if