Subruotine check_block_parameters was introduced.

A few conditions related to the number of processes, dimension of Hamiltonian Matrix and Block Size are now checked. At present, CONQUEST simply stops if inappropriate setting for the block size and MPI processes is given.

Main one is ..
proc_cols must be smaller than blocks_c = (matrix_size_padH/ block size)

src/ScalapackFormat.f90

@@ -255,6 +255,8 @@ contains
 !!    Added timer
 !!   2011/02/13 L.Tong
 !!    Added k-point parallelisation
+!!   2023/08/02 tsuyoshi
+!!    Changes for padding of H and S matrices
 !!  SOURCE
 !!
   subroutine allocate_arrays (nkp)
@@ -271,6 +273,7 @@ contains
 
     ! Local variables
     integer :: stat
+    logical :: flag_err
 
     if(iprint_DM>3.AND.myid==0) write(io_lun,fmt='(10x,i5,a)') myid,' Starting Allocate Arrays'
 
@@ -280,6 +283,8 @@ contains
      blocks_c = ceiling((real(matrix_size,double)-RD_ERR)/block_size_c)
      if(blocks_r .ne. blocks_c) call cq_abort("ScalapackFormat: blocks_r /= blocks_c")
      matrix_size_padH = blocks_r * block_size_r
+     call check_block_parameters(flag_err)
+     if(flag_err) call cq_abort("ScalapacFormat: check_block_parameter ",blocks_c, proc_cols)
     else
      blocks_r = (matrix_size/block_size_r)
      blocks_c = (matrix_size/block_size_c)
@@ -316,6 +321,17 @@ contains
     call stop_timer(tmr_std_allocation)
     return
 1   format(10x,'AllocArr: block sizes are: ',2i5)
+   contains 
+     subroutine check_block_parameters(flag_err)
+      implicit none
+      logical, intent(out):: flag_err
+       flag_err=.false.
+       if(blocks_c < blocks_r) flag_err = .true.
+       if(blocks_c < proc_cols) flag_err = .true.
+       !the next one should not be necessary
+       if(blocks_r < proc_rows) flag_err = .true.
+       return
+     end subroutine check_block_parameters
   end subroutine allocate_arrays
 !!***