Use read_field_chksum in MOM_restart

  Use read_field_chksum and MOM_read_data in MOM_restart.  Also internally
renamed mpp_chksum to just chksum in MOM_restart to aid in identifying
unfiltered dependencies on FMS in MOM_restart.F90.  All answers are bitwise
identical.

src/framework/MOM_restart.F90

@@ -3,24 +3,22 @@ module MOM_restart
 
 ! This file is part of MOM6. See LICENSE.md for the license.
 
-use MOM_domains, only : pe_here, num_PEs
+use MOM_domains, only : PE_here, num_PEs
 use MOM_error_handler, only : MOM_error, FATAL, WARNING, NOTE, is_root_pe
 use MOM_file_parser, only : get_param, log_param, log_version, param_file_type
 use MOM_string_functions, only : lowercase
 use MOM_grid, only : ocean_grid_type
 use MOM_io, only : create_file, fieldtype, file_exists, open_file, close_file
-use MOM_io, only : MOM_read_data, read_data, get_filename_appendix
+use MOM_io, only : MOM_read_data, read_data, get_filename_appendix, read_field_chksum
 use MOM_io, only : get_file_info, get_file_atts, get_file_fields, get_file_times
 use MOM_io, only : vardesc, var_desc, query_vardesc, modify_vardesc
 use MOM_io, only : MULTIPLE, NETCDF_FILE, READONLY_FILE, SINGLE_FILE
 use MOM_io, only : CENTER, CORNER, NORTH_FACE, EAST_FACE
-use MOM_time_manager, only : time_type, time_type_to_real, real_to_time
-use MOM_time_manager, only : days_in_month, get_date, set_date
-use MOM_transform_FMS, only : mpp_chksum => rotated_mpp_chksum
+use MOM_time_manager,  only : time_type, time_type_to_real, real_to_time
+use MOM_time_manager,  only : days_in_month, get_date, set_date
+use MOM_transform_FMS, only : chksum => rotated_mpp_chksum
 use MOM_transform_FMS, only : write_field => rotated_write_field
-use MOM_verticalGrid, only : verticalGrid_type
-use mpp_io_mod,      only :  mpp_attribute_exist, mpp_get_atts
-use mpp_mod,         only :  mpp_pe
+use MOM_verticalGrid,  only : verticalGrid_type
 
 implicit none ; private
 
@@ -116,7 +114,7 @@ module MOM_restart
   module procedure register_restart_field_ptr0d, register_restart_field_0d
 end interface
 
-!> Register a pair of restart fieilds whose rotations map onto each other
+!> Register a pair of restart fields whose rotations map onto each other
 interface register_restart_pair
   module procedure register_restart_pair_ptr2d
   module procedure register_restart_pair_ptr3d
@@ -1010,18 +1008,15 @@ subroutine save_restart(directory, time, G, CS, time_stamped, filename, GV, num_
     endif
     do m=start_var,next_var-1
       if (associated(CS%var_ptr3d(m)%p)) then
-        check_val(m-start_var+1,1) = &
-            mpp_chksum(CS%var_ptr3d(m)%p(isL:ieL,jsL:jeL,:), turns=-turns)
+        check_val(m-start_var+1,1) = chksum(CS%var_ptr3d(m)%p(isL:ieL,jsL:jeL,:), turns=-turns)
       elseif (associated(CS%var_ptr2d(m)%p)) then
-        check_val(m-start_var+1,1) = &
-            mpp_chksum(CS%var_ptr2d(m)%p(isL:ieL,jsL:jeL), turns=-turns)
+        check_val(m-start_var+1,1) = chksum(CS%var_ptr2d(m)%p(isL:ieL,jsL:jeL), turns=-turns)
       elseif (associated(CS%var_ptr4d(m)%p)) then
-        check_val(m-start_var+1,1) = &
-            mpp_chksum(CS%var_ptr4d(m)%p(isL:ieL,jsL:jeL,:,:), turns=-turns)
+        check_val(m-start_var+1,1) = chksum(CS%var_ptr4d(m)%p(isL:ieL,jsL:jeL,:,:), turns=-turns)
       elseif (associated(CS%var_ptr1d(m)%p)) then
-        check_val(m-start_var+1,1) = mpp_chksum(CS%var_ptr1d(m)%p)
+        check_val(m-start_var+1,1) = chksum(CS%var_ptr1d(m)%p)
       elseif (associated(CS%var_ptr0d(m)%p)) then
-        check_val(m-start_var+1,1) = mpp_chksum(CS%var_ptr0d(m)%p,pelist=(/mpp_pe()/))
+        check_val(m-start_var+1,1) = chksum(CS%var_ptr0d(m)%p, pelist=(/PE_here()/))
       endif
     enddo
 
@@ -1100,9 +1095,9 @@ subroutine restore_state(filename, directory, day, G, CS)
   real    :: t1, t2 ! Two times.
   real, allocatable :: time_vals(:)
   type(fieldtype), allocatable :: fields(:)
-  logical                          :: check_exist, is_there_a_checksum
-  integer(kind=8),dimension(3)     :: checksum_file
-  integer(kind=8)                  :: checksum_data
+  logical            :: is_there_a_checksum ! Is there a valid checksum that should be checked.
+  integer(kind=8)    :: checksum_file  ! The checksum value recorded in the input file.
+  integer(kind=8)    :: checksum_data  ! The checksum value for the data that was read in.
 
   if (.not.associated(CS)) call MOM_error(FATAL, "MOM_restart " // &
       "restore_state: Module must be initialized before it is used.")
@@ -1202,25 +1197,21 @@ subroutine restore_state(filename, directory, day, G, CS)
       do i=1, nvar
         call get_file_atts(fields(i),name=varname)
         if (lowercase(trim(varname)) == lowercase(trim(CS%restart_field(m)%var_name))) then
-          check_exist = mpp_attribute_exist(fields(i),"checksum")
-          checksum_file(:) = -1
           checksum_data = -1
-          is_there_a_checksum = .false.
-          if ( check_exist ) then
-            call mpp_get_atts(fields(i),checksum=checksum_file)
-            is_there_a_checksum = .true.
+          if (CS%checksum_required) then
+            call read_field_chksum(fields(i), checksum_file, is_there_a_checksum)
+          else
+            checksum_file = -1
+            is_there_a_checksum = .false. ! Do not need to do data checksumming.
           endif
-          if (.NOT. CS%checksum_required) is_there_a_checksum = .false. ! Do not need to do data checksumming.
 
           if (associated(CS%var_ptr1d(m)%p))  then
             ! Read a 1d array, which should be invariant to domain decomposition.
-            call read_data(unit_path(n), varname, CS%var_ptr1d(m)%p, &
-                           G%Domain%mpp_domain, timelevel=1)
-            if (is_there_a_checksum) checksum_data = mpp_chksum(CS%var_ptr1d(m)%p)
+            call MOM_read_data(unit_path(n), varname, CS%var_ptr1d(m)%p, timelevel=1)
+            if (is_there_a_checksum) checksum_data = chksum(CS%var_ptr1d(m)%p)
           elseif (associated(CS%var_ptr0d(m)%p)) then ! Read a scalar...
-            call read_data(unit_path(n), varname, CS%var_ptr0d(m)%p, &
-                           G%Domain%mpp_domain, timelevel=1)
-            if (is_there_a_checksum) checksum_data = mpp_chksum(CS%var_ptr0d(m)%p,pelist=(/mpp_pe()/))
+            call MOM_read_data(unit_path(n), varname, CS%var_ptr0d(m)%p, timelevel=1)
+            if (is_there_a_checksum) checksum_data = chksum(CS%var_ptr0d(m)%p, pelist=(/PE_here()/))
           elseif (associated(CS%var_ptr2d(m)%p)) then  ! Read a 2d array.
             if (pos /= 0) then
               call MOM_read_data(unit_path(n), varname, CS%var_ptr2d(m)%p, &
@@ -1229,7 +1220,7 @@ subroutine restore_state(filename, directory, day, G, CS)
               call read_data(unit_path(n), varname, CS%var_ptr2d(m)%p, &
                              no_domain=.true., timelevel=1)
             endif
-            if (is_there_a_checksum) checksum_data = mpp_chksum(CS%var_ptr2d(m)%p(isL:ieL,jsL:jeL))
+            if (is_there_a_checksum) checksum_data = chksum(CS%var_ptr2d(m)%p(isL:ieL,jsL:jeL))
           elseif (associated(CS%var_ptr3d(m)%p)) then  ! Read a 3d array.
             if (pos /= 0) then
               call MOM_read_data(unit_path(n), varname, CS%var_ptr3d(m)%p, &
@@ -1238,7 +1229,7 @@ subroutine restore_state(filename, directory, day, G, CS)
               call read_data(unit_path(n), varname, CS%var_ptr3d(m)%p, &
                              no_domain=.true., timelevel=1)
             endif
-            if (is_there_a_checksum) checksum_data = mpp_chksum(CS%var_ptr3d(m)%p(isL:ieL,jsL:jeL,:))
+            if (is_there_a_checksum) checksum_data = chksum(CS%var_ptr3d(m)%p(isL:ieL,jsL:jeL,:))
           elseif (associated(CS%var_ptr4d(m)%p)) then  ! Read a 4d array.
             if (pos /= 0) then
               call MOM_read_data(unit_path(n), varname, CS%var_ptr4d(m)%p, &
@@ -1247,14 +1238,14 @@ subroutine restore_state(filename, directory, day, G, CS)
               call read_data(unit_path(n), varname, CS%var_ptr4d(m)%p, &
                              no_domain=.true., timelevel=1)
             endif
-            if (is_there_a_checksum) checksum_data = mpp_chksum(CS%var_ptr4d(m)%p(isL:ieL,jsL:jeL,:,:))
+            if (is_there_a_checksum) checksum_data = chksum(CS%var_ptr4d(m)%p(isL:ieL,jsL:jeL,:,:))
           else
             call MOM_error(FATAL, "MOM_restart restore_state: No pointers set for "//trim(varname))
           endif
 
-          if (is_root_pe() .and. is_there_a_checksum .and. (checksum_file(1) /= checksum_data)) then
+          if (is_root_pe() .and. is_there_a_checksum .and. (checksum_file /= checksum_data)) then
              write (mesg,'(a,Z16,a,Z16,a)') "Checksum of input field "// trim(varname)//" ",checksum_data,&
-                                          " does not match value ", checksum_file(1), &
+                                          " does not match value ", checksum_file, &
                                           " stored in "//trim(unit_path(n)//"." )
              call MOM_error(FATAL, "MOM_restart(restore_state): "//trim(mesg) )
           endif
@@ -1455,7 +1446,7 @@ function open_restart_units(filename, directory, G, CS, units, file_paths, &
         if (fexists) then
           if (present(units)) &
             call open_file(units(n), trim(filepath), READONLY_FILE, NETCDF_FILE, &
-                           threading = MULTIPLE, fileset = SINGLE_FILE)
+                           threading=MULTIPLE, fileset=SINGLE_FILE)
           if (present(global_files)) global_files(n) = .true.
         elseif (CS%parallel_restartfiles) then
           ! Look for decomposed files using the I/O Layout.
@@ -1484,7 +1475,7 @@ function open_restart_units(filename, directory, G, CS, units, file_paths, &
       if (fexists) then
         if (present(units)) &
           call open_file(units(n), trim(filepath), READONLY_FILE, NETCDF_FILE, &
-                       threading = MULTIPLE, fileset = SINGLE_FILE)
+                       threading=MULTIPLE, fileset=SINGLE_FILE)
         if (present(global_files)) global_files(n) = .true.
         if (present(file_paths)) file_paths(n) = filepath
         n = n + 1