Merge branch 'vijaysm/fix-rof-mesh-usage' (PR #8479)

Fix the ERS.MOS_USRDAT.RMOSNLDAS* cases that were using the wrong ROF mesh file.

We now also perform an additional validation check to determine whether the ROF mesh is in either the SCRIP format for unstructured grids or a domain file format, so we can use the appropriate option to read the grid in parallel through MOAB. We can potentially try to decipher this at the MOAB layer as well, redirecting to SCRIP vs. Domain reader to achieve an equivalent effect.

[BFB]

Author: rljacob

components/mosart/cime_config/testdefs/testmods_dirs/mosart/sediment/user_nl_mosart

@@ -1,5 +1,5 @@
 frivinp_rtm = '$DIN_LOC_ROOT/rof/mosart/MOSART_NLDAS_8th_20160426_20210609d_rslp.nc'
-frivinp_mesh = '$DIN_LOC_ROOT/share/meshes/rof/MOSART_global_8th.scrip.20180211c.nc'
+frivinp_mesh = '$DIN_LOC_ROOT/share/domains/domain.clm/domain.lnd.nldas2_0224x0464_c110415.nc'
 sediflag = .true.
 parafile = '$DIN_LOC_ROOT/rof/mosart/US_reservoir_8th_NLDAS3_updated.nc'
 routingmethod = 2

driver-moab/main/cplcomp_exchange_mod.F90

@@ -856,6 +856,73 @@ subroutine cplcomp_moab_init_ice(infodata, comp, id_old, id_join, mpicom_old, mp
 
   end subroutine cplcomp_moab_init_ice
 
+  subroutine cplcomp_moab_pick_load_options(filename, ropts, ierr)
+      ! Inspect filename's netCDF contents and choose MOAB load options that match
+      ! the file's grid format. MOAB's parallel readers couple format to partition
+      ! method: NCHelperScrip handles SCRIP files and supports RCBZOLTAN; NCHelperDomain
+      ! handles CESM domain files (xc/yc/xv/yv) and supports only SQIJ-family partitions.
+      !
+      ! Detection (in order):
+      !   - 'grid_size' dimension present                 => SCRIP (structured or unstructured)
+      !   - 'xc' or 'yc' variable, or 'ni'+'nj' dims      => CESM domain
+      !     (variable names xc/yc/lon/lat vary across files, but the ni/nj dim pair
+      !     is the canonical CESM/CIME domain-file layout that NCHelperDomain expects)
+      ! Returns ierr /= 0 for unrecognized formats; caller decides whether to abort.
+      use pio,          only: file_desc_t, iosystem_desc_t, &
+                              pio_openfile, pio_closefile, pio_nowrite, &
+                              pio_inq_dimid, pio_inq_varid, pio_seterrorhandling, &
+                              PIO_BCAST_ERROR, PIO_INTERNAL_ERROR, PIO_NOERR
+      use shr_pio_mod,  only: shr_pio_getiosys, shr_pio_getiotype
+
+      character(len=*), intent(in)  :: filename
+      character(len=*), intent(out) :: ropts
+      integer,          intent(out) :: ierr
+
+      type(file_desc_t) :: pioid
+      type(iosystem_desc_t), pointer :: iosys
+      integer :: rcode, iotype, dimid_grid_size, dimid_ni, dimid_nj, varid_xc, varid_yc
+      logical :: is_scrip, is_cesm_domain
+      logical :: has_ni, has_nj, has_xc, has_yc
+
+      ierr = 0
+      is_scrip = .false.
+      is_cesm_domain = .false.
+
+      iosys  => shr_pio_getiosys(CPLID)
+      iotype =  shr_pio_getiotype(CPLID)
+      rcode = pio_openfile(iosys, pioid, iotype, trim(filename), pio_nowrite)
+      if (rcode /= PIO_NOERR) then
+         ierr = 1
+         return
+      endif
+
+      call pio_seterrorhandling(pioid, PIO_BCAST_ERROR)
+
+      ! SCRIP marker: 'grid_size' dimension
+      rcode = pio_inq_dimid(pioid, 'grid_size', dimid_grid_size)
+      if (rcode == PIO_NOERR) then
+         is_scrip = .true.
+      else
+         ! CESM domain markers: any of xc, yc variables OR ni+nj dimension pair
+         has_xc = (pio_inq_varid(pioid, 'xc', varid_xc) == PIO_NOERR)
+         has_yc = (pio_inq_varid(pioid, 'yc', varid_yc) == PIO_NOERR)
+         has_ni = (pio_inq_dimid(pioid, 'ni', dimid_ni) == PIO_NOERR)
+         has_nj = (pio_inq_dimid(pioid, 'nj', dimid_nj) == PIO_NOERR)
+         if (has_xc .or. has_yc .or. (has_ni .and. has_nj)) is_cesm_domain = .true.
+      endif
+
+      call pio_seterrorhandling(pioid, PIO_INTERNAL_ERROR)
+      call pio_closefile(pioid)
+
+      if (is_scrip) then
+         ropts = 'PARALLEL=READ_PART;PARTITION_METHOD=RCBZOLTAN'
+      else if (is_cesm_domain) then
+         ropts = 'PARALLEL=READ_PART;PARTITION_METHOD=SQIJ;VARIABLE=;REPARTITION;NO_CULLING'
+      else
+         ierr = 2
+      endif
+  end subroutine cplcomp_moab_pick_load_options
+
   subroutine cplcomp_moab_init_rof(infodata, comp, id_old, id_join, mpicom_old, mpicom_new, mpicom_join, dead_comps, partMethod, subname)
 
       use iMOAB, only: iMOAB_WriteMesh, iMOAB_GetMeshInfo
@@ -919,12 +986,22 @@ subroutine cplcomp_moab_init_rof(infodata, comp, id_old, id_join, mpicom_old, mp
                ! load mesh from scrip file passed from river model, if domain file is not available
                call seq_infodata_GetData(infodata,rof_mesh=rtm_mesh,rof_domain=rof_domain)
                if ( trim(rof_domain) == 'none' ) then
-                  outfile = trim(rtm_mesh)//C_NULL_CHAR
-                  ropts = 'PARALLEL=READ_PART;PARTITION_METHOD=RCBZOLTAN'//C_NULL_CHAR
+                  outfile = trim(rtm_mesh)
                else
-                  outfile = trim(rof_domain)//C_NULL_CHAR
-                  ropts = 'PARALLEL=READ_PART;PARTITION_METHOD=SQIJ;VARIABLE=;REPARTITION'//C_NULL_CHAR
+                  outfile = trim(rof_domain)
+               endif
+               ! Pick MOAB load options based on actual file format. MOSART's frivinp_mesh
+               ! may be either a SCRIP-format mesh (structured or unstructured, handled by
+               ! NCHelperScrip with RCBZOLTAN) or a CESM domain file (xc/yc/xv/yv, handled
+               ! by NCHelperDomain with SQIJ-family partitions). The two readers don't share
+               ! partition-method support, so the right options depend on the file format.
+               call cplcomp_moab_pick_load_options(trim(outfile), ropts, ierr)
+               if (ierr /= 0) then
+                  write(logunit,*) subname,' cannot determine MOAB load options for ', trim(outfile)
+                  call shr_sys_abort(subname//' ERROR: unrecognized ROF mesh file format: '//trim(outfile))
                endif
+               outfile = trim(outfile)//C_NULL_CHAR
+               ropts = trim(ropts)//C_NULL_CHAR
                nghlay = 0 ! no ghost layers
                if (seq_comm_iamroot(CPLID)) then
                   write(logunit,'(A)') subname//' loading rof from file '//trim(outfile) &