From 4b2d74abcc75f09d23dc2a100eb5b2baa238e6c1 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Tue, 3 Sep 2024 15:54:36 -0400
Subject: [PATCH 01/15] add the capability for an ensemble of nest to have its
 own data_table.yaml

---
 data_override/include/data_override.inc       |  11 +-
 fms2_io/fms_io_utils.F90                      |  13 +-
 test_fms/data_override/Makefile.am            |   4 +-
 .../test_data_override_ensembles.sh           |  92 ++++++++++++
 .../test_data_override_ongrid.F90             | 133 +++++++++++++++++-
 5 files changed, 243 insertions(+), 10 deletions(-)
 create mode 100755 test_fms/data_override/test_data_override_ensembles.sh

diff --git a/data_override/include/data_override.inc b/data_override/include/data_override.inc
index e79ee5d042..e622379f2d 100644
--- a/data_override/include/data_override.inc
+++ b/data_override/include/data_override.inc
@@ -45,7 +45,7 @@ use mpp_domains_mod, only : domainUG, mpp_pass_SG_to_UG, mpp_get_UG_SG_domain, N
 use time_manager_mod, only: time_type, OPERATOR(>), OPERATOR(<)
 use fms2_io_mod,     only : FmsNetcdfFile_t, open_file, close_file, &
                             read_data, fms2_io_init, variable_exists, &
-                            get_mosaic_tile_file, file_exists
+                            get_mosaic_tile_file, file_exists, get_instance_filename
 use get_grid_version_mod, only: get_grid_version_1, get_grid_version_2
 use fms_string_utils_mod, only: string
 
@@ -591,9 +591,16 @@ subroutine read_table_yaml(data_table)
     integer :: nentries, mentries
     integer :: i
     character(len=50) :: buffer
+    character(len=255) :: filename !< Name of the expected data_table.yaml
     integer :: file_id
 
-    file_id = open_and_parse_file("data_table.yaml")
+    ! If doing and ensemble or nest run add the filename appendix (ens_XX or nest_XX) to the filename
+    call get_instance_filename("data_table.yaml", filename)
+    if (file_exists(filename) .and. file_exists("data_table.yaml")) &
+      call mpp_error(FATAL, "Both data_table.yaml and "//trim(filename)//" exists, pick one!")
+
+    file_id = open_and_parse_file(trim(filename))
+
     if (file_id==999) then
       nentries = 0
     else
diff --git a/fms2_io/fms_io_utils.F90 b/fms2_io/fms_io_utils.F90
index cd72c0c8d5..4a41af5ab5 100644
--- a/fms2_io/fms_io_utils.F90
+++ b/fms2_io/fms_io_utils.F90
@@ -809,6 +809,9 @@ subroutine get_instance_filename(name_in,name_out)
   length = len_trim(name_in)
   name_out = name_in(1:length)
 
+  !< If the filename_appendix is not set just return
+  if (trim(filename_appendix) .eq. "") return
+
   if(len_trim(filename_appendix) > 0) then
      !< If .tileXX is in the filename add the appendix before it
      if (has_domain_tile_string(name_in)) then
@@ -822,8 +825,14 @@ subroutine get_instance_filename(name_in,name_out)
      if ( i .ne. 0 ) then
         name_out = name_in(1:i-1)//'.'//trim(filename_appendix)//name_in(i:length)
      else
-     !< If .nc is not in the name, add the appendix at the end of the file
-        name_out = name_in(1:length)  //'.'//trim(filename_appendix)
+        i = index(trim(name_in), ".yaml", back=.true.)
+        if (i .ne. 0) then
+          !< If .yaml is in the filename add the appendix before it
+          name_out = name_in(1:i-1)//'.'//trim(filename_appendix)//name_in(i:length)
+        else
+          !< If .nc  and .yaml are not in the name, add the appendix at the end of the file
+          name_out = name_in(1:length)  //'.'//trim(filename_appendix)
+        endif
      end if
   end if
 
diff --git a/test_fms/data_override/Makefile.am b/test_fms/data_override/Makefile.am
index 087bd91ea3..0de57700f9 100644
--- a/test_fms/data_override/Makefile.am
+++ b/test_fms/data_override/Makefile.am
@@ -73,11 +73,11 @@ TESTS_ENVIRONMENT= test_input_path="@TEST_INPUT_PATH@" \
 # Run the test program.
 
 TESTS = test_data_override2.sh test_data_override_init.sh test_data_override2_mono.sh test_data_override2_ongrid.sh \
-        test_data_override2_scalar.sh test_data_override_weights.sh
+        test_data_override2_scalar.sh test_data_override_weights.sh test_data_override_ensembles.sh
 
 # Include these files with the distribution.
 EXTRA_DIST = test_data_override2.sh test_data_override_init.sh test_data_override2_mono.sh test_data_override2_ongrid.sh \
-             test_data_override2_scalar.sh test_data_override_weights.sh
+             test_data_override2_scalar.sh test_data_override_weights.sh test_data_override_ensembles.sh
 
 # Clean up
 CLEANFILES = input.nml *.nc* *.out diag_table data_table data_table.yaml INPUT/* *.dpi *.spi *.dyn *.spl *-files/*
diff --git a/test_fms/data_override/test_data_override_ensembles.sh b/test_fms/data_override/test_data_override_ensembles.sh
new file mode 100755
index 0000000000..30fe81277a
--- /dev/null
+++ b/test_fms/data_override/test_data_override_ensembles.sh
@@ -0,0 +1,92 @@
+#!/bin/sh
+
+#***********************************************************************
+#*                   GNU Lesser General Public License
+#*
+#* This file is part of the GFDL Flexible Modeling System (FMS).
+#*
+#* FMS is free software: you can redistribute it and/or modify it under
+#* the terms of the GNU Lesser General Public License as published by
+#* the Free Software Foundation, either version 3 of the License, or (at
+#* your option) any later version.
+#*
+#* FMS is distributed in the hope that it will be useful, but WITHOUT
+#* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+#* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+#* for more details.
+#*
+#* You should have received a copy of the GNU Lesser General Public
+#* License along with FMS.  If not, see <http://www.gnu.org/licenses/>.
+#***********************************************************************
+#
+# Copyright (c) 2019-2021 Ed Hartnett, Uriel Ramirez, Seth Underwood
+
+# Set common test settings.
+. ../test-lib.sh
+
+output_dir
+[ ! -d "INPUT" ] && mkdir -p "INPUT"
+
+cat <<_EOF > data_table.ens_01.yaml
+data_table:
+ - grid_name: OCN
+   fieldname_in_model: runoff
+   override_file:
+   - fieldname_in_file: runoff
+     file_name: INPUT/runoff.daitren.clim.1440x1080.v20180328_ens_01.nc
+     interp_method: none
+   factor: 1.0
+_EOF
+
+cat <<_EOF > data_table.ens_02.yaml
+data_table:
+ - grid_name: OCN
+   fieldname_in_model: runoff
+   override_file:
+   - fieldname_in_file: runoff
+     file_name: INPUT/runoff.daitren.clim.1440x1080.v20180328_ens_02.nc
+     interp_method: none
+   factor: 1.0
+_EOF
+
+cat <<_EOF > input.nml
+&data_override_nml
+  use_data_table_yaml = .True.
+/
+
+&test_data_override_ongrid_nml
+  test_case = 5
+/
+
+&ensemble_nml
+   ensemble_size = 2
+/
+_EOF
+
+#The test only runs with yaml
+if [ -z $parser_skip ]; then
+  for KIND in r4 r8
+  do
+    rm -rf INPUT/.
+    test_expect_success "test_data_override with two ensembles  -yaml (${KIND})" '
+      mpirun -n 12 ../test_data_override_ongrid_${KIND}
+      '
+  done
+fi
+
+cat <<_EOF > data_table.yaml
+data_table:
+ - grid_name: OCN
+   fieldname_in_model: runoff
+   override_file:
+   - fieldname_in_file: runoff
+     file_name: INPUT/runoff.daitren.clim.1440x1080.v20180328_ens_02.nc
+     interp_method: none
+   factor: 1.0
+_EOF
+
+test_expect_failure "test_data_override with both data_table.yaml and data_table.ens_xx.yaml files (${KIND})" '
+      mpirun -n 12 ../test_data_override_ongrid_${KIND}
+      '
+rm -rf INPUT
+test_done
diff --git a/test_fms/data_override/test_data_override_ongrid.F90 b/test_fms/data_override/test_data_override_ongrid.F90
index a05eb9d6c8..26e5704e74 100644
--- a/test_fms/data_override/test_data_override_ongrid.F90
+++ b/test_fms/data_override/test_data_override_ongrid.F90
@@ -26,13 +26,16 @@ program test_data_override_ongrid
 use mpp_domains_mod,   only: mpp_define_domains, mpp_define_io_domain, mpp_get_data_domain, &
                              mpp_domains_set_stack_size, mpp_get_compute_domain, domain2d
 use mpp_mod,           only: mpp_init, mpp_exit, mpp_pe, mpp_root_pe, mpp_error, FATAL, &
-                             input_nml_file, mpp_sync, NOTE
+                             input_nml_file, mpp_sync, NOTE, mpp_npes, mpp_get_current_pelist, &
+                             mpp_set_current_pelist
 use data_override_mod, only: data_override_init, data_override
 use fms2_io_mod
 use time_manager_mod,  only: set_calendar_type, time_type, set_date, NOLEAP
 use netcdf,            only: nf90_create, nf90_def_dim, nf90_def_var, nf90_enddef, nf90_put_var, &
                              nf90_close, nf90_put_att, nf90_clobber, nf90_64bit_offset, nf90_char, &
                              nf90_double, nf90_unlimited
+use ensemble_manager_mod, only: get_ensemble_size, ensemble_manager_init
+
 use fms_mod, only: string
 
 implicit none
@@ -52,7 +55,12 @@ program test_data_override_ongrid
 integer, parameter                         :: bilinear = 2
 integer, parameter                         :: scalar = 3
 integer, parameter                         :: weight_file = 4
+integer, parameter                         :: ensemble_case = 5
 integer                                    :: test_case = ongrid
+integer                                    :: npes
+integer, allocatable                       :: pelist(:)
+integer, allocatable                       :: pelist_ens(:)
+integer                                    :: ensemble_id
 
 namelist / test_data_override_ongrid_nml / nhalox, nhaloy, test_case, nlon, nlat, layout
 
@@ -69,12 +77,27 @@ program test_data_override_ongrid
 
 call set_calendar_type(NOLEAP)
 
+npes = mpp_npes()
+allocate(pelist(npes))
+call mpp_get_current_pelist(pelist)
+
+select case (test_case)
+case (ensemble_case)
+  call set_up_ensemble_case()
+end select
+
 !< Create a domain nlonXnlat with mask
 call mpp_domains_set_stack_size(17280000)
 call mpp_define_domains( (/1,nlon,1,nlat/), layout, Domain, xhalo=nhalox, yhalo=nhaloy, name='test_data_override_emc')
 call mpp_define_io_domain(Domain, (/1,1/))
 call mpp_get_data_domain(Domain, is, ie, js, je)
 
+select case (test_case)
+case (ensemble_case)
+  ! Go back to the full pelist
+  call mpp_set_current_pelist(pelist)
+end select
+
 select case (test_case)
 case (ongrid)
   call generate_ongrid_input_file ()
@@ -84,11 +107,19 @@ program test_data_override_ongrid
   call generate_scalar_input_file ()
 case (weight_file)
   call generate_weight_input_file ()
+case (ensemble_case)
+  call generate_ensemble_input_file()
 end select
 
 call mpp_sync()
 call mpp_error(NOTE, "Finished creating INPUT Files")
 
+select case (test_case)
+case (ensemble_case)
+  !< Go back to the ensemble pelist
+  call mpp_set_current_pelist(pelist_ens)
+end select
+
 !< Initiliaze data_override
 call data_override_init(Ocean_domain_in=Domain, mode=lkind)
 
@@ -101,6 +132,9 @@ program test_data_override_ongrid
   call scalar_test()
 case (weight_file)
   call weight_file_test()
+case (ensemble_case)
+  call ensemble_test()
+  call mpp_set_current_pelist(pelist)
 end select
 
 call mpp_exit
@@ -214,17 +248,29 @@ subroutine create_ocean_hgrid_file()
   endif
 end subroutine create_ocean_hgrid_file
 
-subroutine create_ongrid_data_file()
+subroutine create_ongrid_data_file(is_ensemble)
+  logical, intent(in), optional :: is_ensemble
   type(FmsNetcdfFile_t) :: fileobj
   character(len=10) :: dimnames(3)
   real(lkind), allocatable, dimension(:,:,:) :: runoff_in
   real(lkind), allocatable, dimension(:)     :: time_data
+  integer :: offset
+  character(len=256), allocatable :: appendix
+
   integer :: i
 
+  offset = 0
+  appendix = ""
+  if (present(is_ensemble)) then
+    offset = ensemble_id
+    call get_filename_appendix(appendix)
+    appendix = "_"//trim(appendix)
+  endif
+
   allocate(runoff_in(nlon, nlat, 10))
   allocate(time_data(10))
   do i = 1, 10
-    runoff_in(:,:,i) = real(i, lkind)
+    runoff_in(:,:,i) = real(i+offset, lkind)
   enddo
   time_data = (/1., 2., 3., 5., 6., 7., 8., 9., 10., 11./)
 
@@ -232,7 +278,7 @@ subroutine create_ongrid_data_file()
   dimnames(2) = 'j'
   dimnames(3) = 'time'
 
-  if (open_file(fileobj, 'INPUT/runoff.daitren.clim.1440x1080.v20180328.nc', 'overwrite')) then
+  if (open_file(fileobj, 'INPUT/runoff.daitren.clim.1440x1080.v20180328'//trim(appendix)//'.nc', 'overwrite')) then
     call register_axis(fileobj, "i", nlon)
     call register_axis(fileobj, "j", nlat)
     call register_axis(fileobj, "time", unlimited)
@@ -605,4 +651,83 @@ subroutine scalar_test()
 
 end subroutine scalar_test
 
+subroutine set_up_ensemble_case()
+  integer :: ens_siz(6)
+  character(len=10) :: text
+
+  if (npes .ne. 12) &
+    call mpp_error(FATAL, "This test requires 12 pes to run")
+
+  if (layout(1)*layout(2) .ne. 6) &
+    call mpp_error(FATAL, "The two members of the layout do not equal 6")
+
+  call ensemble_manager_init
+  ens_siz = get_ensemble_size()
+  if (ens_siz(1) .ne. 2) &
+    call mpp_error(FATAL, "This test requires 2 ensembles")
+
+  if (mpp_pe() < 6) then
+    !PEs 0-5 are the first ensemble
+    ensemble_id = 1
+    allocate(pelist_ens(npes/ens_siz(1)))
+    pelist_ens = pelist(1:6)
+    call mpp_set_current_pelist(pelist_ens)
+  else
+    !PEs 6-11 are the second ensemble
+    ensemble_id = 2
+    allocate(pelist_ens(npes/ens_siz(1)))
+    pelist_ens = pelist(7:)
+    call mpp_set_current_pelist(pelist_ens)
+  endif
+
+  write( text,'(a,i2.2)' ) 'ens_', ensemble_id
+  call set_filename_appendix(trim(text))
+
+  if (mpp_pe() .eq. mpp_root_pe()) &
+  print *, "ensemble_id:", ensemble_id, ":: ", pelist_ens
+end subroutine
+
+subroutine generate_ensemble_input_file()
+  if (mpp_pe() .eq. mpp_root_pe()) then
+    call create_grid_spec_file ()
+    call create_ocean_mosaic_file()
+    call create_ocean_hgrid_file()
+  endif
+
+  !< Go back to the ensemble pelist so that each root pe can write its own input file
+  call mpp_set_current_pelist(pelist_ens)
+  if (mpp_pe() .eq. mpp_root_pe()) then
+    call create_ongrid_data_file(is_ensemble=.true.)
+  endif
+  call mpp_set_current_pelist(pelist)
+end subroutine
+
+subroutine ensemble_test()
+  real(lkind)                                :: expected_result  !< Expected result from data_override
+  type(time_type)                            :: Time             !< Time
+  real(lkind), allocatable, dimension(:,:)   :: runoff           !< Data to be written
+
+  allocate(runoff(is:ie,js:je))
+
+  runoff = 999._lkind
+  !< Run it when time=3
+  Time = set_date(1,1,4,0,0,0)
+  call data_override('OCN','runoff',runoff, Time)
+  !< Because you are getting the data when time=3, and this is an "ongrid" case, the expected result is just
+  !! equal to the data at time=3, which is 3+ensemble_id.
+  expected_result = 3._lkind + real(ensemble_id,kind=lkind)
+  call compare_data(Domain, runoff, expected_result)
+
+  !< Run it when time=4
+  runoff = 999._lkind
+  Time = set_date(1,1,5,0,0,0)
+  call data_override('OCN','runoff',runoff, Time)
+  !< You are getting the data when time=4, the data at time=3 is 3+ensemble_id. and at time=5 is 4+ensemble_id., so the expected result
+  !! is the average of the 2 (because this is is an "ongrid" case and there is no horizontal interpolation).
+  expected_result = (3._lkind + real(ensemble_id,kind=lkind) + 4._lkind + real(ensemble_id,kind=lkind)) / 2._lkind
+  call compare_data(Domain, runoff, expected_result)
+
+  deallocate(runoff)
+end subroutine ensemble_test
+
 end program test_data_override_ongrid

From 448ac284acfe17bbfb99635394e0eece1cdd6bf2 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Tue, 3 Sep 2024 16:56:41 -0400
Subject: [PATCH 02/15] add the capability for an ensemble of nest to have its
 own diag_table.yaml

---
 diag_manager/fms_diag_yaml.F90          |   8 +-
 test_fms/diag_manager/Makefile.am       |   8 +-
 test_fms/diag_manager/test_ens_runs.F90 | 125 ++++++++++++++++++++++++
 test_fms/diag_manager/test_ens_runs.sh  |  77 +++++++++++++++
 4 files changed, 214 insertions(+), 4 deletions(-)
 create mode 100644 test_fms/diag_manager/test_ens_runs.F90
 create mode 100755 test_fms/diag_manager/test_ens_runs.sh

diff --git a/diag_manager/fms_diag_yaml.F90 b/diag_manager/fms_diag_yaml.F90
index 07b012ef6f..a508d2b491 100644
--- a/diag_manager/fms_diag_yaml.F90
+++ b/diag_manager/fms_diag_yaml.F90
@@ -45,6 +45,7 @@ module fms_diag_yaml_mod
                                 fms_f2c_string
 use platform_mod, only: r4_kind, i4_kind, r8_kind, i8_kind
 use fms_mod, only: lowercase
+use fms2_io_mod, only: file_exists, get_instance_filename
 
 implicit none
 
@@ -381,10 +382,15 @@ subroutine diag_yaml_object_init(diag_subset_output)
                                            !! outputing data at every frequency)
   character(len=:), allocatable :: filename!< Diag file name (for error messages)
   logical              :: is_instantaneous !< .True. if the file is instantaneous (i.e no averaging)
+  character(len=255)   :: yamlfilename     !< Name of the expected diag_table.yaml
 
   if (diag_yaml_module_initialized) return
 
-  diag_yaml_id = open_and_parse_file("diag_table.yaml")
+  ! If doing and ensemble or nest run add the filename appendix (ens_XX or nest_XX) to the filename
+  call get_instance_filename("diag_table.yaml", yamlfilename)
+  if (file_exists(yamlfilename) .and. file_exists("diag_table.yaml")) &
+    call mpp_error(FATAL, "Both diag_table.yaml and "//trim(yamlfilename)//" exists, pick one!")
+  diag_yaml_id = open_and_parse_file(trim(yamlfilename))
 
   call diag_get_value_from_key(diag_yaml_id, 0, "title", diag_yaml%diag_title)
   call get_value_from_key(diag_yaml_id, 0, "base_date", diag_yaml%diag_basedate)
diff --git a/test_fms/diag_manager/Makefile.am b/test_fms/diag_manager/Makefile.am
index a224eb2451..2d7d6440a5 100644
--- a/test_fms/diag_manager/Makefile.am
+++ b/test_fms/diag_manager/Makefile.am
@@ -34,7 +34,7 @@ check_PROGRAMS = test_diag_manager test_diag_manager_time \
  check_time_min check_time_max check_time_sum check_time_avg test_diag_diurnal check_time_diurnal \
  check_time_pow check_time_rms check_subregional test_cell_measures test_var_masks \
  check_var_masks test_multiple_send_data test_diag_out_yaml test_output_every_freq \
- test_dm_weights test_prepend_date
+ test_dm_weights test_prepend_date test_ens_runs
 
 # This is the source code for the test.
 test_output_every_freq_SOURCES = test_output_every_freq.F90
@@ -65,6 +65,7 @@ test_var_masks_SOURCES = test_var_masks.F90
 check_var_masks_SOURCES = check_var_masks.F90
 test_multiple_send_data_SOURCES = test_multiple_send_data.F90
 test_prepend_date_SOURCES = test_prepend_date.F90
+test_ens_runs_SOURCES = test_ens_runs.F90
 
 TEST_EXTENSIONS = .sh
 SH_LOG_DRIVER = env AM_TAP_AWK='$(AWK)' $(SHELL) \
@@ -74,7 +75,7 @@ SH_LOG_DRIVER = env AM_TAP_AWK='$(AWK)' $(SHELL) \
 TESTS = test_diag_manager2.sh test_time_none.sh test_time_min.sh test_time_max.sh test_time_sum.sh \
         test_time_avg.sh test_time_pow.sh test_time_rms.sh test_time_diurnal.sh test_cell_measures.sh \
         test_subregional.sh test_var_masks.sh test_multiple_send_data.sh test_output_every_freq.sh \
-        test_dm_weights.sh test_flush_nc_file.sh test_prepend_date.sh
+        test_dm_weights.sh test_flush_nc_file.sh test_prepend_date.sh test_ens_runs.sh
 
 testing_utils.mod: testing_utils.$(OBJEXT)
 
@@ -82,7 +83,8 @@ testing_utils.mod: testing_utils.$(OBJEXT)
 EXTRA_DIST = test_diag_manager2.sh check_crashes.sh test_time_none.sh test_time_min.sh test_time_max.sh \
              test_time_sum.sh test_time_avg.sh test_time_pow.sh test_time_rms.sh test_time_diurnal.sh \
              test_cell_measures.sh test_subregional.sh test_var_masks.sh test_multiple_send_data.sh \
-             test_flush_nc_file.sh test_dm_weights.sh test_output_every_freq.sh test_prepend_date.sh
+             test_flush_nc_file.sh test_dm_weights.sh test_output_every_freq.sh test_prepend_date.sh \
+             test_ens_runs.sh
 
 if USING_YAML
 skipflag=""
diff --git a/test_fms/diag_manager/test_ens_runs.F90 b/test_fms/diag_manager/test_ens_runs.F90
new file mode 100644
index 0000000000..56c5f757ff
--- /dev/null
+++ b/test_fms/diag_manager/test_ens_runs.F90
@@ -0,0 +1,125 @@
+!***********************************************************************
+!*                   GNU Lesser General Public License
+!*
+!* This file is part of the GFDL Flexible Modeling System (FMS).
+!*
+!* FMS is free software: you can redistribute it and/or modify it under
+!* the terms of the GNU Lesser General Public License as published by
+!* the Free Software Foundation, either version 3 of the License, or (at
+!* your option) any later version.
+!*
+!* FMS is distributed in the hope that it will be useful, but WITHOUT
+!* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+!* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+!* for more details.
+!*
+!* You should have received a copy of the GNU Lesser General Public
+!* License along with FMS.  If not, see <http://www.gnu.org/licenses/>.
+!***********************************************************************
+
+!> @brief  This programs tests diag manager when the file frequency is set to 0 days
+program test_ens_runs
+
+  use fms_mod,          only: fms_init, fms_end, string
+  use diag_manager_mod, only: diag_axis_init, send_data, diag_send_complete, diag_manager_set_time_end, &
+                              register_diag_field, diag_manager_init, diag_manager_end, register_static_field, &
+                              diag_axis_init
+  use time_manager_mod, only: time_type, operator(+), JULIAN, set_time, set_calendar_type, set_date
+  use mpp_mod,          only: FATAL, mpp_error, mpp_npes, mpp_pe, mpp_get_current_pelist, mpp_set_current_pelist
+  use fms2_io_mod,      only: FmsNetcdfFile_t, open_file, close_file, read_data, get_dimension_size, &
+                              set_filename_appendix, get_instance_filename
+  use ensemble_manager_mod, only: get_ensemble_size, ensemble_manager_init
+
+  implicit none
+
+  integer         :: id_var0          !< diag field ids
+  integer         :: id_axis1         !< Id for axis
+  logical         :: used             !< for send_data calls
+  integer         :: ntimes = 48      !< Number of time steps
+  real            :: vdata            !< Buffer to store the data
+  type(time_type) :: Time             !< "Model" time
+  type(time_type) :: Time_step        !< Time step for the "simulation"
+  integer         :: i                !< For do loops
+  integer         :: npes
+  integer, allocatable :: pelist(:)
+  integer :: ensemble_id
+  integer :: ens_siz(6)
+  character(len=10) :: text
+
+  call fms_init
+  call ensemble_manager_init
+  npes = mpp_npes()
+  if (npes .ne. 2) &
+    call mpp_error(FATAL, "This test requires two pes to run")
+
+  allocate(pelist(npes))
+  call mpp_get_current_pelist(pelist)
+
+  ens_siz = get_ensemble_size()
+  if (ens_siz(1) .ne. 2) &
+    call mpp_error(FATAL, "This test requires 2 ensembles")
+
+  if (mpp_pe() < 1) then
+    !< PE 0 is the first ensemble
+    ensemble_id = 1
+    call mpp_set_current_pelist((/0/))
+  else
+    ensemble_id = 2
+    call mpp_set_current_pelist((/1/))
+  endif
+
+  write( text,'(a,i2.2)' ) 'ens_', ensemble_id
+  call set_filename_appendix(trim(text))
+
+  call set_calendar_type(JULIAN)
+  call diag_manager_init
+
+  Time = set_date(2,1,1,0,0,0)
+  Time_step = set_time (3600,0) !< 1 hour
+  call diag_manager_set_time_end(set_date(2,1,3,0,0,0))
+
+  id_var0 = register_diag_field  ('ocn_mod', 'var0', Time)
+
+  do i = 1, ntimes
+    Time = Time + Time_step
+    vdata = real(i) + real(ensemble_id/10.)
+
+    used = send_data(id_var0, vdata, Time)
+    call diag_send_complete(Time_step)
+  enddo
+
+  call diag_manager_end(Time)
+
+  call check_output()
+  call fms_end
+
+  contains
+
+  !< @brief Check the diag manager output
+  subroutine check_output()
+    type(FmsNetcdfFile_t) :: fileobj     !< Fms2io fileobj
+    integer               :: var_size    !< Size of the variable reading
+    real, allocatable     :: var_data(:) !< Buffer to read variable data to
+    integer               :: j           !< For looping
+    character(len=255)    :: filename    !< Name of the diag file
+
+    call get_instance_filename("test_0days.nc", filename)
+    if (.not. open_file(fileobj, filename, "read")) &
+      call mpp_error(FATAL, "Error opening file:"//trim(filename)//" to read")
+
+    call get_dimension_size(fileobj, "time", var_size)
+    if (var_size .ne. 48) call mpp_error(FATAL, "The dimension of time in the file:test_0days is not the "//&
+                                                 "correct size!")
+    allocate(var_data(var_size))
+    var_data = -999.99
+
+    call read_data(fileobj, "var0", var_data)
+    do j = 1, var_size
+      print *, var_data(j), (real(j)+ real(ensemble_id/10.))
+      if (var_data(j) .ne. (real(j)+ real(ensemble_id/10.))) call mpp_error(FATAL, "The variable data for var1 at time level:"//&
+                                                          string(j)//" is not the correct value!")
+    enddo
+
+    call close_file(fileobj)
+  end subroutine check_output
+end program test_ens_runs
diff --git a/test_fms/diag_manager/test_ens_runs.sh b/test_fms/diag_manager/test_ens_runs.sh
new file mode 100755
index 0000000000..f6bd679d8e
--- /dev/null
+++ b/test_fms/diag_manager/test_ens_runs.sh
@@ -0,0 +1,77 @@
+#!/bin/sh
+
+#***********************************************************************
+#*                   GNU Lesser General Public License
+#*
+#* This file is part of the GFDL Flexible Modeling System (FMS).
+#*
+#* FMS is free software: you can redistribute it and/or modify it under
+#* the terms of the GNU Lesser General Public License as published by
+#* the Free Software Foundation, either version 3 of the License, or (at
+#* your option) any later version.
+#*
+#* FMS is distributed in the hope that it will be useful, but WITHOUT
+#* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+#* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+#* for more details.
+#*
+#* You should have received a copy of the GNU Lesser General Public
+#* License along with FMS.  If not, see <http://www.gnu.org/licenses/>.
+#***********************************************************************
+
+# Copyright (c) 2019-2020 Ed Hartnett, Seth Underwood
+
+# Set common test settings.
+. ../test-lib.sh
+
+if [ -z "${skipflag}" ]; then
+# create and enter directory for in/output files
+output_dir
+
+cat <<_EOF > diag_table.ens_01.yaml
+title: test_diag_manager_01
+base_date: 2 1 1 0 0 0
+diag_files:
+- file_name: test_0days
+  time_units: days
+  unlimdim: time
+  freq: 0 days
+  varlist:
+  - module: ocn_mod
+    var_name: var0
+    reduction: none
+    kind: r8
+_EOF
+
+cat <<_EOF > diag_table.ens_02.yaml
+title: test_diag_manager_01
+base_date: 2 1 1 0 0 0
+diag_files:
+- file_name: test_0days
+  time_units: days
+  unlimdim: time
+  freq: 0 days
+  varlist:
+  - module: ocn_mod
+    var_name: var0
+    reduction: none
+    kind: r8
+_EOF
+
+cat <<_EOF > input.nml
+&diag_manager_nml
+  use_modern_diag = .True.
+/
+
+&ensemble_nml
+   ensemble_size = 2
+/
+_EOF
+
+my_test_count=1
+test_expect_success "Running diag_manager with 2 ensembles (test $my_test_count)" '
+  mpirun -n 2 ../test_ens_runs
+'
+
+fi
+test_done

From a1de22cd7208dce4d739a3ee26c63743bcf35503 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Tue, 3 Sep 2024 16:59:08 -0400
Subject: [PATCH 03/15] Minor documentation updates

---
 test_fms/diag_manager/test_ens_runs.F90 | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/test_fms/diag_manager/test_ens_runs.F90 b/test_fms/diag_manager/test_ens_runs.F90
index 56c5f757ff..ae0e1e498c 100644
--- a/test_fms/diag_manager/test_ens_runs.F90
+++ b/test_fms/diag_manager/test_ens_runs.F90
@@ -40,11 +40,11 @@ program test_ens_runs
   type(time_type) :: Time             !< "Model" time
   type(time_type) :: Time_step        !< Time step for the "simulation"
   integer         :: i                !< For do loops
-  integer         :: npes
-  integer, allocatable :: pelist(:)
-  integer :: ensemble_id
-  integer :: ens_siz(6)
-  character(len=10) :: text
+  integer         :: npes             !< Number of pes in the current pelist
+  integer, allocatable :: pelist(:)   !< Full pelist
+  integer         :: ensemble_id      !< The ensemble id
+  integer         :: ens_siz(6)       !< The size of the ensemble
+  character(len=10) :: text           !< The filename appendix
 
   call fms_init
   call ensemble_manager_init

From 34b50c7e60fc11522c73990ea388673e865ab559 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Wed, 4 Sep 2024 08:10:37 -0400
Subject: [PATCH 04/15] minor corrections to the logic

---
 data_override/include/data_override.inc | 6 ++++--
 diag_manager/fms_diag_yaml.F90          | 6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/data_override/include/data_override.inc b/data_override/include/data_override.inc
index e622379f2d..34612b9317 100644
--- a/data_override/include/data_override.inc
+++ b/data_override/include/data_override.inc
@@ -596,8 +596,10 @@ subroutine read_table_yaml(data_table)
 
     ! If doing and ensemble or nest run add the filename appendix (ens_XX or nest_XX) to the filename
     call get_instance_filename("data_table.yaml", filename)
-    if (file_exists(filename) .and. file_exists("data_table.yaml")) &
-      call mpp_error(FATAL, "Both data_table.yaml and "//trim(filename)//" exists, pick one!")
+    if (trim(filename) .ne. "data_table.yaml") then
+      if (file_exists(filename) .and. file_exists("data_table.yaml")) &
+        call mpp_error(FATAL, "Both data_table.yaml and "//trim(filename)//" exists, pick one!")
+    endif
 
     file_id = open_and_parse_file(trim(filename))
 
diff --git a/diag_manager/fms_diag_yaml.F90 b/diag_manager/fms_diag_yaml.F90
index a508d2b491..ebcc502cd1 100644
--- a/diag_manager/fms_diag_yaml.F90
+++ b/diag_manager/fms_diag_yaml.F90
@@ -388,8 +388,10 @@ subroutine diag_yaml_object_init(diag_subset_output)
 
   ! If doing and ensemble or nest run add the filename appendix (ens_XX or nest_XX) to the filename
   call get_instance_filename("diag_table.yaml", yamlfilename)
-  if (file_exists(yamlfilename) .and. file_exists("diag_table.yaml")) &
-    call mpp_error(FATAL, "Both diag_table.yaml and "//trim(yamlfilename)//" exists, pick one!")
+  if (trim(yamlfilename) .ne. "diag_table.yaml") then
+    if (file_exists(yamlfilename) .and. file_exists("diag_table.yaml")) &
+      call mpp_error(FATAL, "Both diag_table.yaml and "//trim(yamlfilename)//" exists, pick one!")
+  endif
   diag_yaml_id = open_and_parse_file(trim(yamlfilename))
 
   call diag_get_value_from_key(diag_yaml_id, 0, "title", diag_yaml%diag_title)

From f2ea7f64aa898b047c0e8db50d70780b9dff7ff6 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Wed, 4 Sep 2024 08:16:17 -0400
Subject: [PATCH 05/15] add a test to check that the code fails when both
 diag_table.yaml and diag_table.ensXX.yaml files are present

---
 .../test_data_override_ensembles.sh           |  2 +-
 test_fms/diag_manager/test_ens_runs.sh        | 20 +++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/test_fms/data_override/test_data_override_ensembles.sh b/test_fms/data_override/test_data_override_ensembles.sh
index 30fe81277a..79497463c9 100755
--- a/test_fms/data_override/test_data_override_ensembles.sh
+++ b/test_fms/data_override/test_data_override_ensembles.sh
@@ -85,7 +85,7 @@ data_table:
    factor: 1.0
 _EOF
 
-test_expect_failure "test_data_override with both data_table.yaml and data_table.ens_xx.yaml files (${KIND})" '
+test_expect_failure "test_data_override with both data_table.yaml and data_table.ens_xx.yaml files" '
       mpirun -n 12 ../test_data_override_ongrid_${KIND}
       '
 rm -rf INPUT
diff --git a/test_fms/diag_manager/test_ens_runs.sh b/test_fms/diag_manager/test_ens_runs.sh
index f6bd679d8e..3534cadb0c 100755
--- a/test_fms/diag_manager/test_ens_runs.sh
+++ b/test_fms/diag_manager/test_ens_runs.sh
@@ -73,5 +73,25 @@ test_expect_success "Running diag_manager with 2 ensembles (test $my_test_count)
   mpirun -n 2 ../test_ens_runs
 '
 
+cat <<_EOF > diag_table.yaml
+title: test_diag_manager_01
+base_date: 2 1 1 0 0 0
+diag_files:
+- file_name: test_0days
+  time_units: days
+  unlimdim: time
+  freq: 0 days
+  varlist:
+  - module: ocn_mod
+    var_name: var0
+    reduction: none
+    kind: r8
+_EOF
+
+my_test_count=`expr $my_test_count + 1`
+test_expect_failure "Running diag_manager with both diag_table.yaml and diag_table.ens_xx.yaml files present (test $my_test_count)" '
+  mpirun -n 2 ../test_ens_runs
+'
+
 fi
 test_done

From 1093e1370f9a50409255b2aac74ce48a80a3e979 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Wed, 4 Sep 2024 08:48:32 -0400
Subject: [PATCH 06/15] add the capability for an ensemble or nest to have its
 own field_table.yaml

---
 field_manager/field_manager.F90               | 15 ++++-
 test_fms/field_manager/test_field_manager2.sh | 42 +++++++++++++
 .../field_manager/test_field_table_read.F90   | 63 ++++++++++++++++++-
 3 files changed, 115 insertions(+), 5 deletions(-)

diff --git a/field_manager/field_manager.F90 b/field_manager/field_manager.F90
index 8d9804c2e1..fc5a8eb8dd 100644
--- a/field_manager/field_manager.F90
+++ b/field_manager/field_manager.F90
@@ -190,7 +190,7 @@ module field_manager_mod
 use    fms_mod, only : lowercase,   &
                        write_version_number, &
                        check_nml_error
-use fms2_io_mod, only: file_exists
+use fms2_io_mod, only: file_exists, get_instance_filename
 use platform_mod, only: r4_kind, r8_kind
 #ifdef use_yaml
 use fm_yaml_mod
@@ -604,18 +604,27 @@ subroutine read_field_table_yaml(nfields, table_name)
 logical                         :: fm_success !< logical for whether fm_change_list was a success
 logical                         :: subparams !< logical whether subparams exist in this iteration
 
+character(len=255) :: filename !< Name of the expected field_table.yaml
+
 if (.not.PRESENT(table_name)) then
    tbl_name = 'field_table.yaml'
 else
    tbl_name = trim(table_name)
 endif
-if (.not. file_exists(trim(tbl_name))) then
+
+call get_instance_filename(tbl_name, filename)
+if (trim(filename) .ne. tbl_name) then
+  if (file_exists(filename) .and. file_exists(tbl_name)) &
+    call mpp_error(FATAL, "Both "//trim(tbl_name)//" and "//trim(filename)//" exists, pick one!")
+endif
+
+if (.not. file_exists(trim(filename))) then
   if(present(nfields)) nfields = 0
   return
 endif
 
 ! Construct my_table object
-call build_fmTable(my_table, trim(tbl_name))
+call build_fmTable(my_table, trim(filename))
 
 do h=1,size(my_table%types)
   do i=1,size(my_table%types(h)%models)
diff --git a/test_fms/field_manager/test_field_manager2.sh b/test_fms/field_manager/test_field_manager2.sh
index 2485701598..313c830a75 100755
--- a/test_fms/field_manager/test_field_manager2.sh
+++ b/test_fms/field_manager/test_field_manager2.sh
@@ -106,6 +106,48 @@ else
   test_expect_success "field table read with use_field_table.yaml = .true." 'mpirun -n 1 ./test_field_table_read'
   test_expect_success "field manager functional r4 with yaml table" 'mpirun -n 2 ./test_field_manager_r4'
   test_expect_success "field manager functional r8 with yaml table" 'mpirun -n 2 ./test_field_manager_r8'
+
+  cat <<_EOF > field_table.ens_01.yaml
+field_table:
+- field_type: tracer
+  modlist:
+  - model_type: atmos_mod
+    varlist:
+    - variable: radon
+    - variable: radon2
+    - variable: radon3
+      longname: bad radon!
+_EOF
+
+  cat <<_EOF > field_table.ens_02.yaml
+field_table:
+- field_type: tracer
+  modlist:
+  - model_type: atmos_mod
+    varlist:
+    - variable: radon
+    - variable: radon2
+    - variable: radon3
+      longname: bad radon!
+    - variable: radon4
+      longname: REALLY bad radon!
+_EOF
+cat <<_EOF > input.nml
+&field_manager_nml
+  use_field_table_yaml = .true.
+/
+&test_field_table_read_nml
+  test_case = 1
+/
+&ensemble_nml
+   ensemble_size = 2
+/
+_EOF
+  test_expect_failure "field manager test with both field_table.yaml and field_table.ens_XX.yaml files present" 'mpirun -n 2 ./test_field_table_read'
+
+  rm -rf field_table.yaml
+
+  test_expect_success "field manager test with 2 ensembles" 'mpirun -n 2 ./test_field_table_read'
 fi
 
 test_done
diff --git a/test_fms/field_manager/test_field_table_read.F90 b/test_fms/field_manager/test_field_table_read.F90
index ba9b125a46..1be2c0b070 100644
--- a/test_fms/field_manager/test_field_table_read.F90
+++ b/test_fms/field_manager/test_field_table_read.F90
@@ -36,15 +36,74 @@ program test_field_table_read
 
 use field_manager_mod, only: field_manager_init
 use fms_mod,           only: fms_init, fms_end
-use mpp_mod, only : mpp_pe, mpp_root_pe, mpp_error, NOTE, FATAL
+use fms2_io_mod,       only: set_filename_appendix
+use ensemble_manager_mod, only: get_ensemble_size, ensemble_manager_init
+use mpp_mod,           only : mpp_pe, mpp_root_pe, mpp_error, NOTE, FATAL, input_nml_file, mpp_npes, &
+                              mpp_set_current_pelist, mpp_get_current_pelist
 
 implicit none
 
 integer :: nfields
+integer :: nfields_expected
+integer :: io_status
+integer :: npes
+integer, allocatable :: pelist(:)
+integer :: ens_siz(6)
+integer :: ensemble_id
+character(len=10) :: text
+integer, parameter :: default_test = 0 
+integer, parameter :: ensemble_test = 1
+
+! namelist parameters
+integer :: test_case = default_test
+
+namelist / test_field_table_read_nml / test_case
 
 call fms_init
+read (input_nml_file, test_field_table_read_nml, iostat=io_status)
+if (io_status > 0) call mpp_error(FATAL,'=>test_field_table_read: Error reading input.nml')
+
+npes = mpp_npes()
+allocate(pelist(npes))
+call mpp_get_current_pelist(pelist)
+
+nfields_expected = 4
+select case (test_case)
+case (ensemble_test)
+  if (npes .ne. 2) &
+    call mpp_error(FATAL, "test_field_table_read:: this test requires 2 PEs!")
+
+  call ensemble_manager_init
+  ens_siz = get_ensemble_size()
+  if (ens_siz(1) .ne. 2) &
+    call mpp_error(FATAL, "This test requires 2 ensembles")
+
+  if (mpp_pe() .eq. 0) then
+    !PEs 0 is the first ensemble
+    ensemble_id = 1
+    call mpp_set_current_pelist((/0/))
+    nfields_expected = 3
+  else
+    !PEs 1 is the second ensemble
+    ensemble_id = 2
+    call mpp_set_current_pelist((/1/))
+    nfields_expected = 4
+  endif
+
+  write( text,'(a,i2.2)' ) 'ens_', ensemble_id
+  call set_filename_appendix(trim(text))
+
+end select
+
 call field_manager_init(nfields)
-if (nfields .ne. 4) &
+print *, nfields
+if (nfields .ne. nfields_expected) &
   call mpp_error(FATAL, "test_field_table_read:: The number fields returned is not the expected result")
+
+select case (test_case)
+case (ensemble_test)
+  call mpp_set_current_pelist(pelist)
+end select 
+
 call fms_end
 end program test_field_table_read

From 58156c20579237e948099830b4d22d4059fc596e Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Wed, 4 Sep 2024 08:51:53 -0400
Subject: [PATCH 07/15] fix line length limit and remove trailing whitespace

---
 test_fms/data_override/test_data_override_ongrid.F90 | 5 +++--
 test_fms/diag_manager/test_ens_runs.F90              | 5 +++--
 test_fms/field_manager/test_field_table_read.F90     | 4 ++--
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/test_fms/data_override/test_data_override_ongrid.F90 b/test_fms/data_override/test_data_override_ongrid.F90
index 26e5704e74..5ed2354dec 100644
--- a/test_fms/data_override/test_data_override_ongrid.F90
+++ b/test_fms/data_override/test_data_override_ongrid.F90
@@ -722,8 +722,9 @@ subroutine ensemble_test()
   runoff = 999._lkind
   Time = set_date(1,1,5,0,0,0)
   call data_override('OCN','runoff',runoff, Time)
-  !< You are getting the data when time=4, the data at time=3 is 3+ensemble_id. and at time=5 is 4+ensemble_id., so the expected result
-  !! is the average of the 2 (because this is is an "ongrid" case and there is no horizontal interpolation).
+  !< You are getting the data when time=4, the data at time=3 is 3+ensemble_id. and at time=5 is 4+ensemble_id.,
+  !! so the expected result is the average of the 2 (because this is is an "ongrid" case and there
+  !! is no horizontal interpolation).
   expected_result = (3._lkind + real(ensemble_id,kind=lkind) + 4._lkind + real(ensemble_id,kind=lkind)) / 2._lkind
   call compare_data(Domain, runoff, expected_result)
 
diff --git a/test_fms/diag_manager/test_ens_runs.F90 b/test_fms/diag_manager/test_ens_runs.F90
index ae0e1e498c..018db0b4b8 100644
--- a/test_fms/diag_manager/test_ens_runs.F90
+++ b/test_fms/diag_manager/test_ens_runs.F90
@@ -116,8 +116,9 @@ subroutine check_output()
     call read_data(fileobj, "var0", var_data)
     do j = 1, var_size
       print *, var_data(j), (real(j)+ real(ensemble_id/10.))
-      if (var_data(j) .ne. (real(j)+ real(ensemble_id/10.))) call mpp_error(FATAL, "The variable data for var1 at time level:"//&
-                                                          string(j)//" is not the correct value!")
+      if (var_data(j) .ne. (real(j)+ real(ensemble_id/10.)))&
+        call mpp_error(FATAL, "The variable data for var1 at time level:"//&
+                              string(j)//" is not the correct value!")
     enddo
 
     call close_file(fileobj)
diff --git a/test_fms/field_manager/test_field_table_read.F90 b/test_fms/field_manager/test_field_table_read.F90
index 1be2c0b070..bb46256cb1 100644
--- a/test_fms/field_manager/test_field_table_read.F90
+++ b/test_fms/field_manager/test_field_table_read.F90
@@ -51,7 +51,7 @@ program test_field_table_read
 integer :: ens_siz(6)
 integer :: ensemble_id
 character(len=10) :: text
-integer, parameter :: default_test = 0 
+integer, parameter :: default_test = 0
 integer, parameter :: ensemble_test = 1
 
 ! namelist parameters
@@ -103,7 +103,7 @@ program test_field_table_read
 select case (test_case)
 case (ensemble_test)
   call mpp_set_current_pelist(pelist)
-end select 
+end select
 
 call fms_end
 end program test_field_table_read

From 1698bbe47722b8a064c2020100245b9cfecb748b Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Wed, 4 Sep 2024 09:33:57 -0400
Subject: [PATCH 08/15] Modify to the diag manager test to be more robust

---
 test_fms/diag_manager/test_ens_runs.F90 | 14 ++++++++------
 test_fms/diag_manager/test_ens_runs.sh  |  8 ++++----
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/test_fms/diag_manager/test_ens_runs.F90 b/test_fms/diag_manager/test_ens_runs.F90
index 018db0b4b8..621016430f 100644
--- a/test_fms/diag_manager/test_ens_runs.F90
+++ b/test_fms/diag_manager/test_ens_runs.F90
@@ -45,6 +45,7 @@ program test_ens_runs
   integer         :: ensemble_id      !< The ensemble id
   integer         :: ens_siz(6)       !< The size of the ensemble
   character(len=10) :: text           !< The filename appendix
+  integer :: expected_ntimes
 
   call fms_init
   call ensemble_manager_init
@@ -63,9 +64,11 @@ program test_ens_runs
     !< PE 0 is the first ensemble
     ensemble_id = 1
     call mpp_set_current_pelist((/0/))
+    expected_ntimes = 48
   else
     ensemble_id = 2
     call mpp_set_current_pelist((/1/))
+    expected_ntimes = 24
   endif
 
   write( text,'(a,i2.2)' ) 'ens_', ensemble_id
@@ -82,7 +85,7 @@ program test_ens_runs
 
   do i = 1, ntimes
     Time = Time + Time_step
-    vdata = real(i) + real(ensemble_id/10.)
+    vdata = real(i)
 
     used = send_data(id_var0, vdata, Time)
     call diag_send_complete(Time_step)
@@ -103,20 +106,19 @@ subroutine check_output()
     integer               :: j           !< For looping
     character(len=255)    :: filename    !< Name of the diag file
 
-    call get_instance_filename("test_0days.nc", filename)
+    call get_instance_filename("test_ens.nc", filename)
     if (.not. open_file(fileobj, filename, "read")) &
       call mpp_error(FATAL, "Error opening file:"//trim(filename)//" to read")
 
     call get_dimension_size(fileobj, "time", var_size)
-    if (var_size .ne. 48) call mpp_error(FATAL, "The dimension of time in the file:test_0days is not the "//&
-                                                 "correct size!")
+    if (var_size .ne. expected_ntimes) call mpp_error(FATAL, "The dimension of time in the file:"//&
+                                                             "test_ens is not the correct size!")
     allocate(var_data(var_size))
     var_data = -999.99
 
     call read_data(fileobj, "var0", var_data)
     do j = 1, var_size
-      print *, var_data(j), (real(j)+ real(ensemble_id/10.))
-      if (var_data(j) .ne. (real(j)+ real(ensemble_id/10.)))&
+      if (var_data(j) .ne. real(j * ensemble_id))&
         call mpp_error(FATAL, "The variable data for var1 at time level:"//&
                               string(j)//" is not the correct value!")
     enddo
diff --git a/test_fms/diag_manager/test_ens_runs.sh b/test_fms/diag_manager/test_ens_runs.sh
index 3534cadb0c..b2e262b69c 100755
--- a/test_fms/diag_manager/test_ens_runs.sh
+++ b/test_fms/diag_manager/test_ens_runs.sh
@@ -32,10 +32,10 @@ cat <<_EOF > diag_table.ens_01.yaml
 title: test_diag_manager_01
 base_date: 2 1 1 0 0 0
 diag_files:
-- file_name: test_0days
+- file_name: test_ens
   time_units: days
   unlimdim: time
-  freq: 0 days
+  freq: 1 hours
   varlist:
   - module: ocn_mod
     var_name: var0
@@ -47,10 +47,10 @@ cat <<_EOF > diag_table.ens_02.yaml
 title: test_diag_manager_01
 base_date: 2 1 1 0 0 0
 diag_files:
-- file_name: test_0days
+- file_name: test_ens
   time_units: days
   unlimdim: time
-  freq: 0 days
+  freq: 2 hours
   varlist:
   - module: ocn_mod
     var_name: var0

From 0e8c3597d6e9c51f560fa7668befa76db096a8f2 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Wed, 4 Sep 2024 12:58:13 -0400
Subject: [PATCH 09/15] Fix logic when checking if multiple tables exist

---
 data_override/include/data_override.inc | 2 +-
 diag_manager/fms_diag_yaml.F90          | 2 +-
 field_manager/field_manager.F90         | 2 +-
 fms2_io/fms_io_utils.F90                | 3 ---
 4 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/data_override/include/data_override.inc b/data_override/include/data_override.inc
index d51e5e7500..9e5eda0a19 100644
--- a/data_override/include/data_override.inc
+++ b/data_override/include/data_override.inc
@@ -596,7 +596,7 @@ subroutine read_table_yaml(data_table)
 
     ! If doing and ensemble or nest run add the filename appendix (ens_XX or nest_XX) to the filename
     call get_instance_filename("data_table.yaml", filename)
-    if (trim(filename) .ne. "data_table.yaml") then
+    if (index(trim(filename), "ens_") .ne. 0) then
       if (file_exists(filename) .and. file_exists("data_table.yaml")) &
         call mpp_error(FATAL, "Both data_table.yaml and "//trim(filename)//" exists, pick one!")
     endif
diff --git a/diag_manager/fms_diag_yaml.F90 b/diag_manager/fms_diag_yaml.F90
index 39c199cd85..7653555561 100644
--- a/diag_manager/fms_diag_yaml.F90
+++ b/diag_manager/fms_diag_yaml.F90
@@ -388,7 +388,7 @@ subroutine diag_yaml_object_init(diag_subset_output)
 
   ! If doing and ensemble or nest run add the filename appendix (ens_XX or nest_XX) to the filename
   call get_instance_filename("diag_table.yaml", yamlfilename)
-  if (trim(yamlfilename) .ne. "diag_table.yaml") then
+  if (index(trim(yamlfilename), "ens_") .ne. 0) then
     if (file_exists(yamlfilename) .and. file_exists("diag_table.yaml")) &
       call mpp_error(FATAL, "Both diag_table.yaml and "//trim(yamlfilename)//" exists, pick one!")
   endif
diff --git a/field_manager/field_manager.F90 b/field_manager/field_manager.F90
index 880f5c51a7..e9e23a3362 100644
--- a/field_manager/field_manager.F90
+++ b/field_manager/field_manager.F90
@@ -615,7 +615,7 @@ subroutine read_field_table_yaml(nfields, table_name)
 endif
 
 call get_instance_filename(tbl_name, filename)
-if (trim(filename) .ne. tbl_name) then
+if (index(trim(filename), "ens_") .ne. 0) then
   if (file_exists(filename) .and. file_exists(tbl_name)) &
     call mpp_error(FATAL, "Both "//trim(tbl_name)//" and "//trim(filename)//" exists, pick one!")
 endif
diff --git a/fms2_io/fms_io_utils.F90 b/fms2_io/fms_io_utils.F90
index 00d5846477..605c7d08e9 100644
--- a/fms2_io/fms_io_utils.F90
+++ b/fms2_io/fms_io_utils.F90
@@ -811,9 +811,6 @@ subroutine get_instance_filename(name_in,name_out)
   length = len_trim(name_in)
   name_out = name_in(1:length)
 
-  !< If the filename_appendix is not set just return
-  if (trim(filename_appendix) .eq. "") return
-
   if(len_trim(filename_appendix) > 0) then
      !< If .tileXX is in the filename add the appendix before it
      if (has_domain_tile_string(name_in)) then

From 1b2e050c9096eb3399996f8c276f45011385ac24 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Wed, 18 Sep 2024 16:37:48 -0400
Subject: [PATCH 10/15] Add documentation, use filename macro instead of
 harcoding length

---
 data_override/README.MD                 | 5 +++++
 data_override/include/data_override.inc | 2 +-
 diag_manager/diag_yaml_format.md        | 4 ++++
 diag_manager/fms_diag_yaml.F90          | 2 +-
 field_manager/field_manager.F90         | 2 +-
 5 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/data_override/README.MD b/data_override/README.MD
index b35879edf2..fd83965638 100644
--- a/data_override/README.MD
+++ b/data_override/README.MD
@@ -8,6 +8,7 @@
 - [Converting legacy data_table to data_table.yaml](README.MD#3-converting-legacy-data_table-to-data_tableyaml)
 - [Examples](README.MD#4-examples)
 - [External Weight File Structure](README.MD#5-external-weight-file-structure)
+- [Ensemble and Nest Support](README.MD#6-ensemble-and-nest-support)
 
 #### 1. YAML Data Table format:
 Each entry in the data_table has the following key values:
@@ -200,3 +201,7 @@ variables:
   - weight(:,:,2) -> (i,j+1)
   - weight(:,:,3) -> (i+1,j)
   - weight(:,:,4) -> (i+1,j+1)
+
+#### 6. Ensemble and Nest Support
+
+It may be desired to have each member of an ensemble use a different forcing file. In other to support this, FMS allows for each ensemble member to have its own data_table.yaml. For example, for a run with 2 ensemble members, fms will search for data_table_ens_01.yaml and data_table_ens_02.yaml. However, if both the data_table.yaml and the data_table_ens_* files are present, the code will crash as only 1 option is allowed. Similary, each nest can have its own data_table (data_table_nest_01.yaml), but in this case FMS will not crash if both data_table_nest_01.yaml and data_table.yaml are present. The main grid will use the data_table.yaml and the first nest will use the data_table_nest_01.yaml file.
\ No newline at end of file
diff --git a/data_override/include/data_override.inc b/data_override/include/data_override.inc
index 9e5eda0a19..c92a7e345e 100644
--- a/data_override/include/data_override.inc
+++ b/data_override/include/data_override.inc
@@ -591,7 +591,7 @@ subroutine read_table_yaml(data_table)
     integer :: nentries, mentries
     integer :: i
     character(len=50) :: buffer
-    character(len=255) :: filename !< Name of the expected data_table.yaml
+    character(len=FMS_FILE_LEN) :: filename !< Name of the expected data_table.yaml
     integer :: file_id
 
     ! If doing and ensemble or nest run add the filename appendix (ens_XX or nest_XX) to the filename
diff --git a/diag_manager/diag_yaml_format.md b/diag_manager/diag_yaml_format.md
index d9e93c3593..b561445fdc 100644
--- a/diag_manager/diag_yaml_format.md
+++ b/diag_manager/diag_yaml_format.md
@@ -15,6 +15,7 @@ The purpose of this document is to explain the diag_table yaml format.
 - [2.6 Sub_region Section](diag_yaml_format.md#26-sub_region-section)
 - [3. More examples](diag_yaml_format.md#3-more-examples)
 - [4. Schema](diag_yaml_format.md#4-schema)
+- [5. Ensemble and Nest Support](diag_yaml_format.md#5-ensemble-and-nest-support)
 
 ### 1. Converting from legacy ascii diag_table format
 
@@ -349,3 +350,6 @@ diag_files:
 A formal specification of the file format, in the form of a JSON schema, can be
 found in the [gfdl_msd_schemas](https://github.com/NOAA-GFDL/gfdl_msd_schemas)
 repository on Github.
+
+### 5. Ensemble and Nest Support
+When using nests, it may be desired for a nest to have a different file frequency or number of variables from the parent grid. This may allow users to save disk space and reduce simulations time. In order to supports, FMS allows each nest to have a different diag_table.yaml from the parent grid. For example, if running with 1 test FMS will use diag_table.yaml for the parent grid and diag_table.nest_01.yaml for the first nest Similary, each ensemble member can have its own diag_table (diag_table_ens_XX.yaml, where XX is the ensemble number). However, for the ensemble case if both the diag_table.yaml and the diag_table_ens_* files are present, the code will crash as only 1 option is allowed.
\ No newline at end of file
diff --git a/diag_manager/fms_diag_yaml.F90 b/diag_manager/fms_diag_yaml.F90
index 7653555561..26f631414c 100644
--- a/diag_manager/fms_diag_yaml.F90
+++ b/diag_manager/fms_diag_yaml.F90
@@ -382,7 +382,7 @@ subroutine diag_yaml_object_init(diag_subset_output)
                                            !! outputing data at every frequency)
   character(len=:), allocatable :: filename!< Diag file name (for error messages)
   logical              :: is_instantaneous !< .True. if the file is instantaneous (i.e no averaging)
-  character(len=255)   :: yamlfilename     !< Name of the expected diag_table.yaml
+  character(len=FMS_FILE_LEN)   :: yamlfilename     !< Name of the expected diag_table.yaml
 
   if (diag_yaml_module_initialized) return
 
diff --git a/field_manager/field_manager.F90 b/field_manager/field_manager.F90
index e9e23a3362..ba26417195 100644
--- a/field_manager/field_manager.F90
+++ b/field_manager/field_manager.F90
@@ -606,7 +606,7 @@ subroutine read_field_table_yaml(nfields, table_name)
 logical                         :: fm_success !< logical for whether fm_change_list was a success
 logical                         :: subparams !< logical whether subparams exist in this iteration
 
-character(len=255) :: filename !< Name of the expected field_table.yaml
+character(len=FMS_FILE_LEN) :: filename !< Name of the expected field_table.yaml
 
 if (.not.PRESENT(table_name)) then
    tbl_name = 'field_table.yaml'

From a440d01cae396b07a538b33e292702df1cce90c3 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Thu, 19 Sep 2024 08:01:42 -0400
Subject: [PATCH 11/15] include FMS_FILE_LEN in data_override_mod

---
 data_override/include/data_override.inc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/data_override/include/data_override.inc b/data_override/include/data_override.inc
index c92a7e345e..17360d0b85 100644
--- a/data_override/include/data_override.inc
+++ b/data_override/include/data_override.inc
@@ -21,7 +21,7 @@
 ! modules. These modules are not intended to be used directly - they should be
 ! used through the data_override_mod API. See data_override.F90 for details.
 
-use platform_mod, only: r4_kind, r8_kind, FMS_PATH_LEN
+use platform_mod, only: r4_kind, r8_kind, FMS_PATH_LEN, FMS_FILE_LEN
 use yaml_parser_mod
 use constants_mod, only: DEG_TO_RAD
 use mpp_mod, only : mpp_error, FATAL, WARNING, NOTE, stdout, stdlog, mpp_max

From e0ddce0d1c217796d8b0f172918065cc38af38d0 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Thu, 19 Sep 2024 10:06:13 -0400
Subject: [PATCH 12/15] move the failure test

---
 test_fms/data_override/test_data_override_ensembles.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test_fms/data_override/test_data_override_ensembles.sh b/test_fms/data_override/test_data_override_ensembles.sh
index 79497463c9..334586c723 100755
--- a/test_fms/data_override/test_data_override_ensembles.sh
+++ b/test_fms/data_override/test_data_override_ensembles.sh
@@ -72,7 +72,6 @@ if [ -z $parser_skip ]; then
       mpirun -n 12 ../test_data_override_ongrid_${KIND}
       '
   done
-fi
 
 cat <<_EOF > data_table.yaml
 data_table:
@@ -85,8 +84,9 @@ data_table:
    factor: 1.0
 _EOF
 
-test_expect_failure "test_data_override with both data_table.yaml and data_table.ens_xx.yaml files" '
+    test_expect_failure "test_data_override with both data_table.yaml and data_table.ens_xx.yaml files" '
       mpirun -n 12 ../test_data_override_ongrid_${KIND}
       '
 rm -rf INPUT
+fi
 test_done

From 32db3c006155c2c588d53ad10004ee5f17041e90 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Thu, 26 Sep 2024 10:59:01 -0400
Subject: [PATCH 13/15] refactor unit test to hopefully prevent unit test
 failures

---
 .../data_override/test_data_override2_mono.sh | 18 +++-
 .../test_data_override2_ongrid.sh             | 10 ++-
 .../test_data_override2_scalar.sh             | 13 ++-
 .../test_data_override_ensembles.sh           |  9 +-
 .../test_data_override_ongrid.F90             | 87 ++++++++++---------
 .../test_data_override_weights.sh             |  9 +-
 6 files changed, 96 insertions(+), 50 deletions(-)

diff --git a/test_fms/data_override/test_data_override2_mono.sh b/test_fms/data_override/test_data_override2_mono.sh
index be1cce4103..05c833389a 100755
--- a/test_fms/data_override/test_data_override2_mono.sh
+++ b/test_fms/data_override/test_data_override2_mono.sh
@@ -27,9 +27,10 @@
 output_dir
 [ ! -d "INPUT" ] && mkdir -p "INPUT"
 
-cat <<_EOF > input.nml
+cat <<_EOF > input_base.nml
 &test_data_override_ongrid_nml
   test_case = 2
+  write_only = .False.
 /
 _EOF
 
@@ -41,6 +42,12 @@ _EOF
 for KIND in r4 r8
 do
   rm -rf INPUT/*
+  sed 's/write_only = .False./write_only = .True./g' input_base.nml > input.nml
+  test_expect_success "Creating input files (${KIND})" '
+      mpirun -n 6 ../test_data_override_ongrid_${KIND}
+      '
+
+  cp input_base.nml input.nml
   test_expect_success "test_data_override with monotonically increasing and decreasing data sets (${KIND})" '
     mpirun -n 6 ../test_data_override_ongrid_${KIND}
     '
@@ -48,9 +55,10 @@ done
 
 rm -rf data_table
 
-cat <<_EOF > input.nml
+cat <<_EOF > input_base.nml
 &test_data_override_ongrid_nml
   test_case = 2
+  write_only = .False.
 /
 &data_override_nml
   use_data_table_yaml = .True.
@@ -80,6 +88,12 @@ if [ -z $parser_skip ]; then
   for KIND in r4 r8
   do
     rm -rf INPUT/*
+    sed 's/write_only = .False./write_only = .True./g' input_base.nml > input.nml
+    test_expect_success "Creating input files (${KIND})" '
+      mpirun -n 6 ../test_data_override_ongrid_${KIND}
+      '
+
+    cp input_base.nml input.nml
     test_expect_success "test_data_override with monotonically increasing and decreasing data sets  -yaml (${KIND})" '
       mpirun -n 6 ../test_data_override_ongrid_${KIND}
       '
diff --git a/test_fms/data_override/test_data_override2_ongrid.sh b/test_fms/data_override/test_data_override2_ongrid.sh
index e9f36712ce..4f4bc7db8c 100755
--- a/test_fms/data_override/test_data_override2_ongrid.sh
+++ b/test_fms/data_override/test_data_override2_ongrid.sh
@@ -36,6 +36,7 @@ use_data_table_yaml=.False.
 &test_data_override_ongrid_nml
   nhalox=halo_size
   nhaloy=halo_size
+  write_only = .False.
 /
 _EOF
   printf '"OCN", "runoff", "runoff", "./INPUT/runoff.daitren.clim.1440x1080.v20180328.nc", "none" ,  1.0' | cat > data_table
@@ -48,6 +49,7 @@ use_data_table_yaml=.True.
 &test_data_override_ongrid_nml
   nhalox=halo_size
   nhaloy=halo_size
+  write_only = .False.
 /
 _EOF
 cat <<_EOF > data_table.yaml
@@ -66,18 +68,22 @@ fi
 for KIND in r4 r8
 do
 rm -rf INPUT/*
+sed -e 's/halo_size/2/g ; s/write_only = .False./write_only = .True./g' input_base.nml > input.nml
+
+test_expect_success "Creating input files (${KIND})" '
+  mpirun -n 6 ../test_data_override_ongrid_${KIND}
+'
+
 sed 's/halo_size/2/g' input_base.nml > input.nml
 test_expect_success "data_override on grid with 2 halos in x and y (${KIND})" '
   mpirun -n 6 ../test_data_override_ongrid_${KIND}
 '
 
-rm -rf INPUT/*
 sed 's/halo_size/0/g' input_base.nml > input.nml
 test_expect_success "data_override on grid with 0 halos in x and y (${KIND})" '
   mpirun -n 6 ../test_data_override_ongrid_${KIND}
 '
 
-rm -rf INPUT/*
 test_expect_success "data_override get_grid_v1 (${KIND})" '
   mpirun -n 1 ../test_get_grid_v1_${KIND}
 '
diff --git a/test_fms/data_override/test_data_override2_scalar.sh b/test_fms/data_override/test_data_override2_scalar.sh
index ac19b2b0a6..319684d12a 100755
--- a/test_fms/data_override/test_data_override2_scalar.sh
+++ b/test_fms/data_override/test_data_override2_scalar.sh
@@ -28,22 +28,24 @@ output_dir
 rm -rf data_table data_table.yaml input.nml input_base.nml
 
 if [ ! -z $parser_skip ]; then
-  cat <<_EOF > input.nml
+  cat <<_EOF > input_base.nml
 &data_override_nml
 use_data_table_yaml=.False.
 /
 &test_data_override_ongrid_nml
   test_case = 3
+  write_only = .False.
 /
 _EOF
   printf '"OCN", "co2", "co2", "./INPUT/scalar.nc", "none" ,  1.0' | cat > data_table
 else
-cat <<_EOF > input.nml
+cat <<_EOF > input_base.nml
 &data_override_nml
 use_data_table_yaml=.True.
 /
 &test_data_override_ongrid_nml
   test_case = 3
+  write_only = .False.
 /
 _EOF
 cat <<_EOF > data_table.yaml
@@ -62,10 +64,15 @@ fi
 for KIND in r4 r8
 do
 rm -rf INPUT/*
-test_expect_success "data_override scalar field (${KIND})" '
+sed 's/write_only = .False./write_only = .True./g' input_base.nml > input.nml
+test_expect_success "Creating input files (${KIND})" '
   mpirun -n 6 ../test_data_override_ongrid_${KIND}
 '
 
+cp input_base.nml input.nml
+test_expect_success "data_override scalar field (${KIND})" '
+  mpirun -n 6 ../test_data_override_ongrid_${KIND}
+'
 done
 rm -rf INPUT *.nc # remove any leftover files to reduce size
 
diff --git a/test_fms/data_override/test_data_override_ensembles.sh b/test_fms/data_override/test_data_override_ensembles.sh
index 334586c723..afcdcd458f 100755
--- a/test_fms/data_override/test_data_override_ensembles.sh
+++ b/test_fms/data_override/test_data_override_ensembles.sh
@@ -49,13 +49,14 @@ data_table:
    factor: 1.0
 _EOF
 
-cat <<_EOF > input.nml
+cat <<_EOF > input_base.nml
 &data_override_nml
   use_data_table_yaml = .True.
 /
 
 &test_data_override_ongrid_nml
   test_case = 5
+  write_only = .False.
 /
 
 &ensemble_nml
@@ -68,6 +69,12 @@ if [ -z $parser_skip ]; then
   for KIND in r4 r8
   do
     rm -rf INPUT/.
+    sed 's/write_only = .False./write_only = .True./g' input_base.nml > input.nml
+    test_expect_success "Creating input files (${KIND})" '
+      mpirun -n 12 ../test_data_override_ongrid_${KIND}
+    '
+
+    cp input_base.nml input.nml
     test_expect_success "test_data_override with two ensembles  -yaml (${KIND})" '
       mpirun -n 12 ../test_data_override_ongrid_${KIND}
       '
diff --git a/test_fms/data_override/test_data_override_ongrid.F90 b/test_fms/data_override/test_data_override_ongrid.F90
index 5ed2354dec..e9ddcff28c 100644
--- a/test_fms/data_override/test_data_override_ongrid.F90
+++ b/test_fms/data_override/test_data_override_ongrid.F90
@@ -36,7 +36,7 @@ program test_data_override_ongrid
                              nf90_double, nf90_unlimited
 use ensemble_manager_mod, only: get_ensemble_size, ensemble_manager_init
 
-use fms_mod, only: string
+use fms_mod, only: string, fms_init, fms_end
 
 implicit none
 
@@ -61,10 +61,12 @@ program test_data_override_ongrid
 integer, allocatable                       :: pelist(:)
 integer, allocatable                       :: pelist_ens(:)
 integer                                    :: ensemble_id
+logical                                    :: write_only=.false. !< True if creating the input files only
+                                                                 !! False if running the tests only
 
-namelist / test_data_override_ongrid_nml / nhalox, nhaloy, test_case, nlon, nlat, layout
+namelist / test_data_override_ongrid_nml / nhalox, nhaloy, test_case, nlon, nlat, layout, write_only
 
-call mpp_init
+call fms_init
 call fms2_io_init
 
 read (input_nml_file, test_data_override_ongrid_nml, iostat=io_status)
@@ -98,46 +100,49 @@ program test_data_override_ongrid
   call mpp_set_current_pelist(pelist)
 end select
 
-select case (test_case)
-case (ongrid)
-  call generate_ongrid_input_file ()
-case (bilinear)
-  call generate_bilinear_input_file ()
-case (scalar)
-  call generate_scalar_input_file ()
-case (weight_file)
-  call generate_weight_input_file ()
-case (ensemble_case)
-  call generate_ensemble_input_file()
-end select
-
-call mpp_sync()
-call mpp_error(NOTE, "Finished creating INPUT Files")
-
-select case (test_case)
-case (ensemble_case)
-  !< Go back to the ensemble pelist
-  call mpp_set_current_pelist(pelist_ens)
-end select
-
-!< Initiliaze data_override
-call data_override_init(Ocean_domain_in=Domain, mode=lkind)
+if (write_only) then
+  select case (test_case)
+  case (ongrid)
+    call generate_ongrid_input_file ()
+  case (bilinear)
+    call generate_bilinear_input_file ()
+  case (scalar)
+    call generate_scalar_input_file ()
+  case (weight_file)
+    call generate_weight_input_file ()
+  case (ensemble_case)
+    call generate_ensemble_input_file()
+  end select
 
-select case (test_case)
-case (ongrid)
-  call ongrid_test()
-case (bilinear)
-  call bilinear_test()
-case (scalar)
-  call scalar_test()
-case (weight_file)
-  call weight_file_test()
-case (ensemble_case)
-  call ensemble_test()
-  call mpp_set_current_pelist(pelist)
-end select
+  call mpp_sync()
+  call mpp_error(NOTE, "Finished creating INPUT Files")
 
-call mpp_exit
+else
+  select case (test_case)
+  case (ensemble_case)
+    !< Go back to the ensemble pelist
+    call mpp_set_current_pelist(pelist_ens)
+  end select
+
+  !< Initiliaze data_override
+  call data_override_init(Ocean_domain_in=Domain, mode=lkind)
+
+  select case (test_case)
+  case (ongrid)
+    call ongrid_test()
+  case (bilinear)
+    call bilinear_test()
+  case (scalar)
+    call scalar_test()
+  case (weight_file)
+    call weight_file_test()
+  case (ensemble_case)
+    call ensemble_test()
+    call mpp_set_current_pelist(pelist)
+  end select
+endif
+
+call fms_end
 
 contains
 
diff --git a/test_fms/data_override/test_data_override_weights.sh b/test_fms/data_override/test_data_override_weights.sh
index a3bc8902e4..bf8810e892 100755
--- a/test_fms/data_override/test_data_override_weights.sh
+++ b/test_fms/data_override/test_data_override_weights.sh
@@ -48,7 +48,7 @@ data_table:
   factor: 1.0
 _EOF
 
-cat <<_EOF > input.nml
+cat <<_EOF > input_base.nml
 &data_override_nml
   use_data_table_yaml = .True.
 /
@@ -58,6 +58,7 @@ cat <<_EOF > input.nml
   nlon = 5
   nlat = 6
   layout = 1, 2
+  write_only = .False.
 /
 _EOF
 
@@ -66,6 +67,12 @@ if [ -z $parser_skip ]; then
   for KIND in r4 r8
   do
     rm -rf INPUT/.
+    sed 's/write_only = .False./write_only = .True./g' input_base.nml > input.nml
+    test_expect_success "Creating input files (${KIND})" '
+      mpirun -n 2 ../test_data_override_ongrid_${KIND}
+    '
+
+    cp input_base.nml input.nml
     test_expect_success "test_data_override with and without weight files  -yaml (${KIND})" '
       mpirun -n 2 ../test_data_override_ongrid_${KIND}
       '

From f7e0b9bbf5e5a3b958a5b727c848cfe999527d63 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Wed, 9 Oct 2024 08:23:04 -0400
Subject: [PATCH 14/15] revert unwanted changes in some data_override test
 scripts

---
 test_fms/data_override/test_data_override2_ongrid.sh | 1 +
 test_fms/data_override/test_data_override2_scalar.sh | 1 +
 2 files changed, 2 insertions(+)

diff --git a/test_fms/data_override/test_data_override2_ongrid.sh b/test_fms/data_override/test_data_override2_ongrid.sh
index 104a5a874e..4d4616734c 100755
--- a/test_fms/data_override/test_data_override2_ongrid.sh
+++ b/test_fms/data_override/test_data_override2_ongrid.sh
@@ -83,6 +83,7 @@ test_expect_success "data_override on grid with 0 halos in x and y (${KIND})" '
   mpirun -n 6 ../test_data_override_ongrid_${KIND}
 '
 
+rm -rf INPUT/*
 test_expect_success "data_override get_grid_v1 (${KIND})" '
   mpirun -n 1 ../test_get_grid_v1_${KIND}
 '
diff --git a/test_fms/data_override/test_data_override2_scalar.sh b/test_fms/data_override/test_data_override2_scalar.sh
index 319684d12a..6b6c096b7a 100755
--- a/test_fms/data_override/test_data_override2_scalar.sh
+++ b/test_fms/data_override/test_data_override2_scalar.sh
@@ -73,6 +73,7 @@ cp input_base.nml input.nml
 test_expect_success "data_override scalar field (${KIND})" '
   mpirun -n 6 ../test_data_override_ongrid_${KIND}
 '
+
 done
 rm -rf INPUT *.nc # remove any leftover files to reduce size
 

From 88751941c3f2aea8f183c92f75bd841d30ff3026 Mon Sep 17 00:00:00 2001
From: Uriel Ramirez <uramirez8707@gmail.com>
Date: Wed, 9 Oct 2024 08:25:41 -0400
Subject: [PATCH 15/15] one more revert

---
 test_fms/data_override/test_data_override_weights.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test_fms/data_override/test_data_override_weights.sh b/test_fms/data_override/test_data_override_weights.sh
index bf8810e892..2bb1e2c3f1 100755
--- a/test_fms/data_override/test_data_override_weights.sh
+++ b/test_fms/data_override/test_data_override_weights.sh
@@ -67,6 +67,7 @@ if [ -z $parser_skip ]; then
   for KIND in r4 r8
   do
     rm -rf INPUT/.
+
     sed 's/write_only = .False./write_only = .True./g' input_base.nml > input.nml
     test_expect_success "Creating input files (${KIND})" '
       mpirun -n 2 ../test_data_override_ongrid_${KIND}