adding mpi process id and num of processes to elpa index

src/elpa_impl.F90

@@ -255,9 +255,10 @@ module elpa_impl
     subroutine set_or_check_missing_comm_params(self)
       implicit none
       class(elpa_impl_t), intent(inout)   :: self
-      integer                             :: mpi_comm_rows, mpi_comm_cols, mpierr, error, &
-                                             my_prow, my_pcol, present_my_prow, present_my_pcol, &
-                                             np_rows, np_cols, present_np_rows, present_np_cols
+      integer                             :: mpi_comm_parent, mpi_comm_rows, mpi_comm_cols, mpierr, error, &
+                                             my_prow, my_pcol, my_id, present_my_prow, present_my_pcol, present_my_id, &
+                                             np_rows, np_cols, np_total, present_np_rows, present_np_cols, present_np_total, &
+                                             is_process_id_zero
       if (.not. (self%is_set("mpi_comm_rows") == 1 .and. self%is_set("mpi_comm_cols") == 1) ) then
         print *,"MPI row and column communicators not set correctly. Aborting..."
         stop
@@ -308,6 +309,54 @@ module elpa_impl
       else
         call self%set("process_col", my_pcol, error)
       endif
+
+
+      ! sadly, at the moment, the parent mpi communicator is not required to be set, e.g. in legacy tests
+      ! we thus cannot obtain process_id
+      ! we can, however, determine the number of prcesses and determine, whether the given process has id 0, 
+      ! assuming, that that is the wan with row and column ids == 0
+      is_process_id_zero = 0
+      if (self%is_set("mpi_comm_parent") == 1) then
+        call self%get("mpi_comm_parent", mpi_comm_parent, error)
+
+        call mpi_comm_size(mpi_comm_parent, np_total, mpierr)
+        if(self%is_set("num_processes") == 1) then
+          call self%get("num_processes", present_np_total, error)
+          if(np_total .ne. present_np_total) then
+            print *,"MPI parent communicator not set correctly. Aborting..."
+            stop
+          endif
+        else
+          call self%set("num_processes", np_total, error)
+        endif
+
+        if(np_total .ne. np_rows * np_cols) then
+          print *,"MPI parent communicator and row/col communicators do not match. Aborting..."
+          stop
+        endif
+
+        call mpi_comm_rank(mpi_comm_parent, my_id, mpierr)
+        if(self%is_set("process_id") == 1) then
+          call self%get("process_id", present_my_id, error)
+          if(my_id .ne. present_my_id) then
+            print *,"MPI parent communicator not set correctly. Aborting..."
+            stop
+          endif
+        else
+          call self%set("process_id", my_id, error)
+        endif
+
+        if(my_id == 0) &
+          is_process_id_zero = 1
+      else
+        ! we can set number of processes and whether process id is zero, but not the process id.
+        ! we assume, that my_pcol == 0 && my_prow == 0  <==> my_id == 0
+        call self%set("num_process", np_rows * np_cols, error)
+        if((my_prow == 0) .and. (my_pcol == 0)) &
+          is_process_id_zero = 1
+      endif
+        call self%set("is_process_id_zero", is_process_id_zero, error)
+
     end subroutine
 
     !> \brief function to setup an ELPA object and to store the MPI communicators internally

src/elpa_index.c

@@ -168,8 +168,11 @@ static const elpa_index_int_entry_t int_entries[] = {
         INT_PARAMETER_ENTRY("local_ncols", "Number of matrix columns stored on this process", NULL),
         INT_PARAMETER_ENTRY("process_row", "Process row number in the 2D domain decomposition", NULL),
         INT_PARAMETER_ENTRY("process_col", "Process column number in the 2D domain decomposition", NULL),
+        INT_PARAMETER_ENTRY("process_id", "Process rank", NULL),
+        INT_PARAMETER_ENTRY("is_process_id_zero", "Is it a process with rank zero?", NULL),
         INT_PARAMETER_ENTRY("num_process_rows", "Number of process row number in the 2D domain decomposition", NULL),
         INT_PARAMETER_ENTRY("num_process_cols", "Number of process column number in the 2D domain decomposition", NULL),
+        INT_PARAMETER_ENTRY("num_processes", "Total number of processes", NULL),
         INT_PARAMETER_ENTRY("bandwidth", "If specified, a band matrix with this bandwidth is expected as input; bandwidth must be multiply of nblk", bw_is_valid),
         INT_PARAMETER_ENTRY("suppress_warnings", "If specified, warnings will NOT be printed on this mpi rank", NULL),
         INT_ANY_ENTRY("mpi_comm_rows", "Communicator for inter-row communication"),
@@ -1024,15 +1027,18 @@ int elpa_index_print_autotune_parameters(elpa_index_t index, int autotune_level,
 }
 
 int elpa_index_print_all_parameters(elpa_index_t index) {
-        for (int i = 0; i < nelements(int_entries); i++) {
-                fprintf(stderr, " %s = ", int_entries[i].base.name);
-                if (int_entries[i].to_string) {
-                        fprintf(stderr, " %s\n", int_entries[i].to_string(index->int_options.values[i]));
-                } else {
-                        fprintf(stderr, " %d\n", index->int_options.values[i]);
+        int process_id = elpa_index_get_int_value(index, "process_id", NULL);
+        if(process_id == 0){
+                for (int i = 0; i < nelements(int_entries); i++) {
+                        fprintf(stderr, " %s = ", int_entries[i].base.name);
+                        if (int_entries[i].to_string) {
+                                fprintf(stderr, " %s\n", int_entries[i].to_string(index->int_options.values[i]));
+                        } else {
+                                fprintf(stderr, " %d\n", index->int_options.values[i]);
+                        }
                 }
+                fprintf(stderr, "\n");
         }
-        fprintf(stderr, "\n");
 
         return 1;
 }