From 8be03135976eb2d80fb2adac0e2a97f87aeef2b9 Mon Sep 17 00:00:00 2001
From: rem1776 <Ryan.Mulhall@noaa.gov>
Date: Fri, 28 Jul 2023 16:27:39 -0400
Subject: [PATCH] add tests for more coverage

---
 test_fms/time_interp/test_time_interp2.sh     |  29 +-
 .../time_interp/test_time_interp_external.F90 | 515 ++++++++++++------
 2 files changed, 369 insertions(+), 175 deletions(-)

diff --git a/test_fms/time_interp/test_time_interp2.sh b/test_fms/time_interp/test_time_interp2.sh
index b982cc71b4..0f30909e7e 100755
--- a/test_fms/time_interp/test_time_interp2.sh
+++ b/test_fms/time_interp/test_time_interp2.sh
@@ -22,7 +22,7 @@
 # This is part of the GFDL FMS package. This is a shell script to
 # execute tests in the test_fms/mpp directory.
 
-# Ed Hartnett 11/29/19
+# Ed Hartnett 11/49/19
 
 # Set common test settings.
 . ../test-lib.sh
@@ -34,20 +34,35 @@ rm -rf INPUT
 mkdir INPUT
 # Run the test.
 test_expect_success "test time interpolation with r8_kind" '
-  mpirun -n 2 ./test_time_interp_r8
+  mpirun -n 4 ./test_time_interp_r8
 '
 test_expect_success "test time interpolation with r4_kind" '
-  mpirun -n 2 ./test_time_interp_r4
+  mpirun -n 4 ./test_time_interp_r4
 '
 
 rm -rf INPUT
 mkdir INPUT
 
-test_expect_success "test time interpolation external with r8_kind" '
-  mpirun -n 2 ./test_time_interp_external_r8
+# nml for calender type
+cat <<_EOF > input.nml
+&test_time_interp_external_nml
+cal_type="julian"
+/
+_EOF
+
+test_expect_success "test time interpolation external with r8_kind (julian)" '
+  mpirun -n 4 ./test_time_interp_external_r8
+'
+test_expect_success "test time interpolation external with r4_kind (julian)" '
+  mpirun -n 4 ./test_time_interp_external_r4
+'
+sed -i 's/julian/no_leap/' input.nml
+
+test_expect_success "test time interpolation external with r8_kind (no_leap)" '
+  mpirun -n 4 ./test_time_interp_external_r8
 '
-test_expect_success "test time interpolation external with r4_kind" '
-  mpirun -n 2 ./test_time_interp_external_r4
+test_expect_success "test time interpolation external with r4_kind (no_leap)" '
+  mpirun -n 4 ./test_time_interp_external_r4
 '
 
 test_done
diff --git a/test_fms/time_interp/test_time_interp_external.F90 b/test_fms/time_interp/test_time_interp_external.F90
index a00eed1c52..a4c3941868 100644
--- a/test_fms/time_interp/test_time_interp_external.F90
+++ b/test_fms/time_interp/test_time_interp_external.F90
@@ -43,14 +43,11 @@ program test_time_interp_external
 
 integer            :: id !< Time_interp_external id
 integer            :: i  !< Index for loops
+integer            :: ierr !< io return status
 character(len=128) :: filename='INPUT/aerosol.climatology.nc'
 character(len=128) :: fieldname='so4_anthro'
 type(time_type)    :: time !< "model" time
 integer, parameter :: kindl = TI_TEST_KIND_
-real(TI_TEST_KIND_), allocatable  :: data_d_3d(:,:,:) !< interpolated data in compute domain
-real(TI_TEST_KIND_), allocatable  :: data_g_3d(:,:,:) !< interpolated global data
-real(TI_TEST_KIND_), allocatable  :: data_d_2d(:,:) !< interpolated data in compute domain
-real(TI_TEST_KIND_), allocatable  :: data_g_2d(:,:) !< interpolated global data
 real(TI_TEST_KIND_) :: data_d_0d = 1.0_kindl !< interpolated data in compute domain
 real(TI_TEST_KIND_) :: data_g_0d = 1.0_kindl !< interpolated global data
 type(domain2d)     :: domain !<Domain to interpolate data to
@@ -65,15 +62,13 @@ program test_time_interp_external
 type(horiz_interp_type) :: Hinterp !< horix interp type
 real(TI_TEST_KIND_)               :: lon_out(180,89) !< lat grid to interpolate to (global)
 real(TI_TEST_KIND_)               :: lat_out(180,89) !< lon grid to interpolate to (global)
-real(TI_TEST_KIND_), allocatable  :: lon_local_out(:,:) !< lat grid to interpolate to (compute)
-real(TI_TEST_KIND_), allocatable  :: lat_local_out(:,:) !< lon grid to interpolate to (compute)
-real(TI_TEST_KIND_), allocatable  :: lon_in(:) !< lat grid in file
-real(TI_TEST_KIND_), allocatable  :: lat_in(:) !< lat grid in file
 integer            :: outunit !< stdout unit number
 type(FmsNetcdfFile_t) :: fileobj !< fileobj
-character(len=12)  :: axis_names(4) !< axis_names
+character(len=12)  :: axis_names(4) = (/ "lon ", "lat ", "time", "none"/) !< axis_names
 real(TI_TEST_KIND_), allocatable  :: data_in(:,:)  !< data added to file
 
+namelist /test_time_interp_external_nml/ cal_type
+
 call mpp_init
 call constants_init
 call fms2_io_init
@@ -82,45 +77,10 @@ program test_time_interp_external
 call time_manager_init
 call horiz_interp_init
 
-!< Create a file to test with:
-if (mpp_pe() .eq. mpp_root_pe()) then
-    if (open_file(fileobj, filename, "overwrite")) then
-        call register_axis(fileobj, "lon", 179)
-        call register_axis(fileobj, "lat", 89)
-        call register_axis(fileobj, "time", unlimited)
-
-        call register_field(fileobj, "lon", "double", dimensions=(/"lon"/))
-        call register_field(fileobj, "lat", "double", dimensions=(/"lat"/))
-        call register_field(fileobj, "time", "double", dimensions=(/"time"/))
-
-        call register_field(fileobj, fieldname, "double", dimensions=(/"lon ", "lat ", "time"/))
-        call register_field(fileobj, trim(fieldname)//"_random", "double", dimensions=(/"lon ", "lat ", "time"/))
-
-        call register_variable_attribute(fileobj, "lon", "cartesian_axis", "X", str_len=1)
-        call register_variable_attribute(fileobj, "lat", "cartesian_axis", "Y", str_len=1)
-
-        call register_variable_attribute(fileobj, "time", "cartesian_axis", "T", str_len=1)
-        call register_variable_attribute(fileobj, "time", "units", "days since 1800-01-01 00:00:00", str_len=30)
-        call register_variable_attribute(fileobj, "time", "calendar", "julian", str_len=6)
+read (input_nml_file, test_time_interp_external_nml, iostat=ierr)
+ierr = check_nml_error (ierr, 'test_time_interp_external_nml')
 
-        call write_data(fileobj, "lat", (/(-90.0_kindl+i*2.0_kindl,i=1,89)/))
-        call write_data(fileobj, "lon", (/(-180.0_kindl+i*2.0_kindl,i=1,179)/))
-        call write_data(fileobj, "time", (/(1+i*2, i=0,2)/))
-
-        allocate(data_in(179, 89))
-        do i=0, 2
-            data_in = real((1+i*2), TI_TEST_KIND_)
-            call write_data(fileobj, fieldname, data_in, unlim_dim_level=i+1)
-
-            call random_number(data_in)
-            call write_data(fileobj, trim(fieldname)//"_random", data_in, unlim_dim_level=i+1)
-        enddo
-        call close_file(fileobj)
-    endif
-endif
-
-!< Wait for the root pe to catch up
-call mpp_sync()
+call create_input_files
 
 select case (trim(cal_type))
 case ('julian')
@@ -131,128 +91,347 @@ program test_time_interp_external
    call mpp_error(FATAL,'invalid calendar type')
 end select
 
-outunit = stdout()
-write(outunit,*) 'INTERPOLATING NON DECOMPOSED FIELDS'
-write(outunit,*) '======================================'
-!< Here every rank is on the same x/y grid
-
-id = init_external_field(filename,fieldname,verbose=.false.)
-fld_size = get_external_field_size(id)
-allocate(data_g_3d(fld_size(1),fld_size(2),fld_size(3)))
-data_g_3d = 0
-
-!< Corresponds to time=1 in the file, so no time_interpolation
-time = set_date(1800,1,2,0,0,0)
-call time_interp_external(id,time,data_g_3d,verbose=.true.)
-sm = sum(data_g_3d)
-mn = minval(data_g_3d)
-mx = maxval(data_g_3d)
-write(outunit,*) 'sum= ', sm
-write(outunit,*) 'max= ', mx
-write(outunit,*) 'min= ', mn
-
-!< Corresponds to time=2, so there will be time_interpolation between time=1 and
-!time =3 in the file
-time = set_date(1800,1,3,0,0,0)
-call time_interp_external(id,time,data_g_3d,verbose=.true.)
-sm = sum(data_g_3d)
-mn = minval(data_g_3d)
-mx = maxval(data_g_3d)
-write(outunit,*) 'sum= ', sm
-write(outunit,*) 'max= ', mx
-write(outunit,*) 'min= ', mn
-
-write(outunit,*) 'INTERPOLATING DOMAIN DECOMPOSED FIELDS'
-write(outunit,*) '======================================'
-!< Here every rank has its own section
-
-call mpp_define_layout((/1,fld_size(1),1,fld_size(2)/),mpp_npes(),layout)
-call mpp_define_domains((/1,fld_size(1),1,fld_size(2)/),layout,domain)
-call mpp_get_compute_domain(domain,isc,iec,jsc,jec)
-call mpp_get_compute_domain(domain,isd,ied,jsd,jed)
-
-call mpp_domains_set_stack_size(fld_size(1)*fld_size(2)*min(fld_size(3),1)*2)
-allocate(data_d_3d(isd:ied,jsd:jed,fld_size(3)))
-data_d_3d = 0
-
-id = init_external_field(filename,fieldname,domain=domain, verbose=.false.)
-
-time = set_date(1800,1,2,0,0,0)
-call time_interp_external(id,time,data_d_3d,verbose=.true.)
-sm = mpp_global_sum(domain,data_d_3d,flags=BITWISE_EXACT_SUM)
-mx = mpp_global_max(domain,data_d_3d)
-mn = mpp_global_min(domain,data_d_3d)
-write(outunit,*) 'global sum= ', sm
-write(outunit,*) 'global max= ', mx
-write(outunit,*) 'global min= ', mn
-
-!< Corresponds to time=2, so there will be time_interpolation between time=1 and
-!time =3 in the file
-time = set_date(1800,1,3,0,0,0)
-call time_interp_external(id,time,data_d_3d,verbose=.true.)
-sm = mpp_global_sum(domain,data_d_3d,flags=BITWISE_EXACT_SUM)
-mx = mpp_global_max(domain,data_d_3d)
-mn = mpp_global_min(domain,data_d_3d)
-write(outunit,*) 'global sum= ', sm
-write(outunit,*) 'global max= ', mx
-write(outunit,*) 'global min= ', mn
-
-write(outunit,*) 'INTERPOLATING DOMAIN DECOMPOSED FIELDS USING HORIZ INTERP'
-write(outunit,*) '======================================'
-!< Here there will be interpolation in x/y/time
-
-! define a global 2 degree output grid
-do i=1,180
-   lon_out(i,:) = 2.0_kindl*real(i,kindl)*atan(1.0_kindl)/45.0_kindl
-enddo
-
-do i=1,89
-   lat_out(:,i) = (i-45)*2.0_kindl*atan(1.0_kindl)/45.0_kindl
-enddo
-
-id = init_external_field(filename,trim(fieldname)//"_random",domain=domain,axis_names=axis_names,&
-      verbose=.false., override=.true.)
-
-if (.not. get_external_fileobj(filename, fileobj)) call mpp_error(FATAL, "Couldn't find the fileobj for: "// &
-    & trim(filename))
-
-allocate (lon_local_out(isc:iec,jsc:jec))
-allocate (lat_local_out(isc:iec,jsc:jec))
-
-lon_local_out(isc:iec,jsc:jec) = lon_out(isc:iec,jsc:jec)
-lat_local_out(isc:iec,jsc:jec) = lat_out(isc:iec,jsc:jec)
-
-!< Read in the axis data
-allocate(lon_in(fld_size(1)+1))
-allocate(lat_in(fld_size(2)+1))
-
-call axis_edges(fileobj, axis_names(1), lon_in)
-call axis_edges(fileobj, axis_names(2), lat_in)
-
-lon_in = lon_in*atan(1.0_kindl)/45.0_kindl
-lat_in = lat_in*atan(1.0_kindl)/45.0_kindl
-
-call horiz_interp_new(Hinterp,lon_in,lat_in, lon_local_out, lat_local_out, &
-     interp_method='bilinear')
-
-deallocate(data_d_3d)
-allocate(data_d_3d(isc:iec,jsc:jec,fld_size(3)))
-
-time = set_date(1800,1,3,0,0,0)
-data_d_3d = 0.0_kindl
-call time_interp_external(id,time,data_d_3d,verbose=.true.,horz_interp=Hinterp)
-sm = mpp_global_sum(domain,data_d_3d,flags=BITWISE_EXACT_SUM)
-mx = mpp_global_max(domain,data_d_3d)
-mn = mpp_global_min(domain,data_d_3d)
-write(outunit,*) 'global sum= ', sm
-write(outunit,*) 'global max= ', mx
-write(outunit,*) 'global min= ', mn
-
-sm = mpp_global_sum(domain,data_d_3d,flags=BITWISE_EXACT_SUM)
-write(outunit,*) 'n valid points= ', sm
-
-call horiz_interp_del(Hinterp)
+call time_interpolate_3d_data
+call time_interpolate_2d_data
+call time_interpolate_scalar_data
+
 call time_interp_external_exit
 call mpp_exit
 
+
+ contains
+
+    !> Writes netcdf input files with fields to interpolate
+    subroutine create_input_files
+        !< Create a file to test with:
+        if (mpp_pe() .eq. mpp_root_pe()) then
+            if (open_file(fileobj, filename, "overwrite")) then
+                call register_axis(fileobj, "lon", 179)
+                call register_axis(fileobj, "lat", 89)
+                call register_axis(fileobj, "time", unlimited)
+
+                call register_field(fileobj, "lon", "double", dimensions=(/"lon"/))
+                call register_field(fileobj, "lat", "double", dimensions=(/"lat"/))
+                call register_field(fileobj, "time", "double", dimensions=(/"time"/))
+
+                call register_field(fileobj, fieldname, "double", dimensions=(/"lon ", "lat ", "time"/))
+                call register_field(fileobj, trim(fieldname)//"_random", "double", dimensions=(/"lon ", "lat ", "time"/))
+
+                call register_variable_attribute(fileobj, "lon", "cartesian_axis", "X", str_len=1)
+                call register_variable_attribute(fileobj, "lat", "cartesian_axis", "Y", str_len=1)
+
+                call register_variable_attribute(fileobj, "time", "cartesian_axis", "T", str_len=1)
+                call register_variable_attribute(fileobj, "time", "units", "days since 1800-01-01 00:00:00", str_len=30)
+                call register_variable_attribute(fileobj, "time", "calendar", "julian", str_len=6)
+
+                !call register_global_attribute(fileobj, "global_scalar", 1024.0_r8_kind)
+
+                call write_data(fileobj, "lat", (/(-90.0_kindl+i*2.0_kindl,i=1,89)/))
+                call write_data(fileobj, "lon", (/(-180.0_kindl+i*2.0_kindl,i=1,179)/))
+                call write_data(fileobj, "time", (/(1+i*2, i=0,2)/))
+
+                allocate(data_in(179, 89))
+                do i=0, 2
+                    data_in = real((1+i*2), TI_TEST_KIND_)
+                    call write_data(fileobj, fieldname, data_in, unlim_dim_level=i+1)
+                    call random_number(data_in)
+                    call write_data(fileobj, trim(fieldname)//"_random", data_in, unlim_dim_level=i+1)
+                enddo
+                call close_file(fileobj)
+            endif
+        endif
+        !< Wait for the root pe to catch up
+        call mpp_sync()
+    end subroutine
+
+    subroutine time_interpolate_3d_data
+        real(TI_TEST_KIND_), allocatable  :: data_d_3d(:,:,:) !< interpolated data in compute domain
+        real(TI_TEST_KIND_), allocatable  :: data_g_3d(:,:,:) !< interpolated global data
+        real(TI_TEST_KIND_), allocatable  :: lon_local_out(:,:) !< lat grid to interpolate to (compute)
+        real(TI_TEST_KIND_), allocatable  :: lat_local_out(:,:) !< lon grid to interpolate to (compute)
+        real(TI_TEST_KIND_), allocatable  :: lon_in(:) !< lat grid in file
+        real(TI_TEST_KIND_), allocatable  :: lat_in(:) !< lat grid in file
+
+        outunit = stdout()
+        write(outunit,*) 'INTERPOLATING NON DECOMPOSED FIELDS'
+        write(outunit,*) '======================================'
+        !< Here every rank is on the same x/y grid
+
+        id = init_external_field(filename,fieldname,verbose=.false.)
+        fld_size = get_external_field_size(id)
+        allocate(data_g_3d(fld_size(1),fld_size(2),fld_size(3)))
+        data_g_3d = 0.0_kindl
+
+        !< Corresponds to time=1 in the file, so no time_interpolation
+        time = set_date(1800,1,2,0,0,0)
+        call time_interp_external(id,time,data_g_3d,verbose=.true.)
+        sm = sum(data_g_3d)
+        mn = minval(data_g_3d)
+        mx = maxval(data_g_3d)
+        write(outunit,*) 'sum= ', sm
+        write(outunit,*) 'max= ', mx
+        write(outunit,*) 'min= ', mn
+
+        !< Corresponds to time=2, so there will be time_interpolation between time=1 and
+        !time =3 in the file
+        time = set_date(1800,1,3,0,0,0)
+        call time_interp_external(id,time,data_g_3d,verbose=.true.)
+        sm = sum(data_g_3d)
+        mn = minval(data_g_3d)
+        mx = maxval(data_g_3d)
+        write(outunit,*) 'sum= ', sm
+        write(outunit,*) 'max= ', mx
+        write(outunit,*) 'min= ', mn
+
+        write(outunit,*) 'INTERPOLATING DOMAIN DECOMPOSED FIELDS'
+        write(outunit,*) '======================================'
+        !< Here every rank has its own section
+
+        call mpp_define_layout((/1,fld_size(1),1,fld_size(2)/),mpp_npes(),layout)
+        call mpp_define_domains((/1,fld_size(1),1,fld_size(2)/),layout,domain)
+        call mpp_get_compute_domain(domain,isc,iec,jsc,jec)
+        call mpp_get_compute_domain(domain,isd,ied,jsd,jed)
+
+        call mpp_domains_set_stack_size(fld_size(1)*fld_size(2)*min(fld_size(3),1)*2)
+        allocate(data_d_3d(isd:ied,jsd:jed,fld_size(3)))
+        data_d_3d = 0
+
+        id = init_external_field(filename,fieldname,domain=domain, verbose=.false.)
+
+        time = set_date(1800,1,2,0,0,0)
+        call time_interp_external(id,time,data_d_3d,verbose=.true.)
+        sm = mpp_global_sum(domain,data_d_3d,flags=BITWISE_EXACT_SUM)
+        mx = mpp_global_max(domain,data_d_3d)
+        mn = mpp_global_min(domain,data_d_3d)
+        write(outunit,*) 'global sum= ', sm
+        write(outunit,*) 'global max= ', mx
+        write(outunit,*) 'global min= ', mn
+
+        !< Corresponds to time=2, so there will be time_interpolation between time=1 and
+        !time =3 in the file
+        time = set_date(1800,1,3,0,0,0)
+        call time_interp_external(id,time,data_d_3d,verbose=.true.)
+        sm = mpp_global_sum(domain,data_d_3d,flags=BITWISE_EXACT_SUM)
+        mx = mpp_global_max(domain,data_d_3d)
+        mn = mpp_global_min(domain,data_d_3d)
+        write(outunit,*) 'global sum= ', sm
+        write(outunit,*) 'global max= ', mx
+        write(outunit,*) 'global min= ', mn
+
+        write(outunit,*) 'INTERPOLATING DOMAIN DECOMPOSED FIELDS USING HORIZ INTERP'
+        write(outunit,*) '======================================'
+        !< Here there will be interpolation in x/y/time
+
+        ! define a global 2 degree output grid
+        do i=1,180
+        lon_out(i,:) = 2.0_kindl*real(i,kindl)*atan(1.0_kindl)/45.0_kindl
+        enddo
+
+        do i=1,89
+        lat_out(:,i) = (i-45)*2.0_kindl*atan(1.0_kindl)/45.0_kindl
+        enddo
+
+        id = init_external_field(filename,trim(fieldname)//"_random",domain=domain,axis_names=axis_names,&
+            verbose=.false., override=.true.)
+
+        if (.not. get_external_fileobj(filename, fileobj)) call mpp_error(FATAL, "Couldn't find the fileobj for: "// &
+            & trim(filename))
+
+        allocate (lon_local_out(isc:iec,jsc:jec))
+        allocate (lat_local_out(isc:iec,jsc:jec))
+
+        lon_local_out(isc:iec,jsc:jec) = lon_out(isc:iec,jsc:jec)
+        lat_local_out(isc:iec,jsc:jec) = lat_out(isc:iec,jsc:jec)
+
+        !< Read in the axis data
+        allocate(lon_in(fld_size(1)+1))
+        allocate(lat_in(fld_size(2)+1))
+
+        call axis_edges(fileobj, axis_names(1), lon_in)
+        call axis_edges(fileobj, axis_names(2), lat_in)
+
+        lon_in = lon_in*atan(1.0_kindl)/45.0_kindl
+        lat_in = lat_in*atan(1.0_kindl)/45.0_kindl
+
+        call horiz_interp_new(Hinterp,lon_in,lat_in, lon_local_out, lat_local_out, &
+            interp_method='bilinear')
+
+        deallocate(data_d_3d)
+        allocate(data_d_3d(isc:iec,jsc:jec,fld_size(3)))
+
+        time = set_date(1800,1,3,0,0,0)
+        data_d_3d = 0.0_kindl
+        call time_interp_external(id,time,data_d_3d,verbose=.true.,horz_interp=Hinterp)
+        sm = mpp_global_sum(domain,data_d_3d,flags=BITWISE_EXACT_SUM)
+        mx = mpp_global_max(domain,data_d_3d)
+        mn = mpp_global_min(domain,data_d_3d)
+        write(outunit,*) 'global sum= ', sm
+        write(outunit,*) 'global max= ', mx
+        write(outunit,*) 'global min= ', mn
+
+        sm = mpp_global_sum(domain,data_d_3d,flags=BITWISE_EXACT_SUM)
+        write(outunit,*) 'n valid points= ', sm
+
+        call horiz_interp_del(Hinterp)
+
+        deallocate(data_d_3d, data_g_3d, lon_local_out, lat_local_out, lon_in, lat_in)
+    end subroutine time_interpolate_3d_data
+
+    subroutine time_interpolate_2d_data
+        real(TI_TEST_KIND_), allocatable  :: data_d_2d(:,:) !< interpolated data in compute domain
+        real(TI_TEST_KIND_), allocatable  :: data_g_2d(:,:) !< interpolated global data
+        real(TI_TEST_KIND_), allocatable  :: lon_local_out(:,:) !< lat grid to interpolate to (compute)
+        real(TI_TEST_KIND_), allocatable  :: lat_local_out(:,:) !< lon grid to interpolate to (compute)
+        real(TI_TEST_KIND_), allocatable  :: lon_in(:) !< lat grid in file
+        real(TI_TEST_KIND_), allocatable  :: lat_in(:) !< lat grid in file
+
+        outunit = stdout()
+        write(outunit,*) 'INTERPOLATING NON DECOMPOSED FIELDS'
+        write(outunit,*) '======================================'
+        !< Here every rank is on the same x/y grid
+
+        id = init_external_field(filename,fieldname,verbose=.false.)
+        fld_size = get_external_field_size(id)
+        allocate(data_g_2d(fld_size(1),fld_size(2)))
+        data_g_2d = 0.0_kindl
+
+        !< Corresponds to time=1 in the file, so no time_interpolation
+        time = set_date(1800,1,2,0,0,0)
+        call time_interp_external(id,time,data_g_2d,verbose=.true.)
+        sm = sum(data_g_2d)
+        mn = minval(data_g_2d)
+        mx = maxval(data_g_2d)
+        write(outunit,*) 'sum= ', sm
+        write(outunit,*) 'max= ', mx
+        write(outunit,*) 'min= ', mn
+
+        !< Corresponds to time=2, so there will be time_interpolation between time=1 and
+        !time =3 in the file
+        time = set_date(1800,1,3,0,0,0)
+        call time_interp_external(id,time,data_g_2d,verbose=.true.)
+        sm = sum(data_g_2d)
+        mn = minval(data_g_2d)
+        mx = maxval(data_g_2d)
+        write(outunit,*) 'sum= ', sm
+        write(outunit,*) 'max= ', mx
+        write(outunit,*) 'min= ', mn
+
+        write(outunit,*) 'INTERPOLATING DOMAIN DECOMPOSED FIELDS'
+        write(outunit,*) '======================================'
+        !< Here every rank has its own section
+
+        call mpp_define_layout((/1,fld_size(1),1,fld_size(2)/),mpp_npes(),layout)
+        call mpp_define_domains((/1,fld_size(1),1,fld_size(2)/),layout,domain)
+        call mpp_get_compute_domain(domain,isc,iec,jsc,jec)
+        call mpp_get_compute_domain(domain,isd,ied,jsd,jed)
+
+        call mpp_domains_set_stack_size(fld_size(1)*fld_size(2)*min(fld_size(3),1)*2)
+        allocate(data_d_2d(isd:ied,jsd:jed))
+        data_d_2d = 0
+
+        id = init_external_field(filename,fieldname,domain=domain, verbose=.false.)
+
+        time = set_date(1800,1,2,0,0,0)
+        call time_interp_external(id,time,data_d_2d,verbose=.true.)
+        sm = mpp_global_sum(domain,data_d_2d,flags=BITWISE_EXACT_SUM)
+        mx = mpp_global_max(domain,data_d_2d)
+        mn = mpp_global_min(domain,data_d_2d)
+        write(outunit,*) 'global sum= ', sm
+        write(outunit,*) 'global max= ', mx
+        write(outunit,*) 'global min= ', mn
+
+        !< Corresponds to time=2, so there will be time_interpolation between time=1 and
+        !time =3 in the file
+        time = set_date(1800,1,3,0,0,0)
+        call time_interp_external(id,time,data_d_2d,verbose=.true.)
+        sm = mpp_global_sum(domain,data_d_2d,flags=BITWISE_EXACT_SUM)
+        mx = mpp_global_max(domain,data_d_2d)
+        mn = mpp_global_min(domain,data_d_2d)
+        write(outunit,*) 'global sum= ', sm
+        write(outunit,*) 'global max= ', mx
+        write(outunit,*) 'global min= ', mn
+
+        write(outunit,*) 'INTERPOLATING DOMAIN DECOMPOSED FIELDS USING HORIZ INTERP'
+        write(outunit,*) '======================================'
+        !< Here there will be interpolation in x/y/time
+
+        ! define a global 2 degree output grid
+        do i=1,180
+        lon_out(i,:) = 2.0_kindl*real(i,kindl)*atan(1.0_kindl)/45.0_kindl
+        enddo
+
+        do i=1,89
+        lat_out(:,i) = (i-45)*2.0_kindl*atan(1.0_kindl)/45.0_kindl
+        enddo
+
+        id = init_external_field(filename,trim(fieldname)//"_random",domain=domain,axis_names=axis_names,&
+            verbose=.false., override=.true.)
+
+        if (.not. get_external_fileobj(filename, fileobj)) call mpp_error(FATAL, "Couldn't find the fileobj for: "// &
+            & trim(filename))
+
+        allocate (lon_local_out(isc:iec,jsc:jec))
+        allocate (lat_local_out(isc:iec,jsc:jec))
+
+        lon_local_out(isc:iec,jsc:jec) = lon_out(isc:iec,jsc:jec)
+        lat_local_out(isc:iec,jsc:jec) = lat_out(isc:iec,jsc:jec)
+
+        !< Read in the axis data
+        allocate(lon_in(fld_size(1)+1))
+        allocate(lat_in(fld_size(2)+1))
+
+        call axis_edges(fileobj, axis_names(1), lon_in)
+        call axis_edges(fileobj, axis_names(2), lat_in)
+
+        lon_in = lon_in*atan(1.0_kindl)/45.0_kindl
+        lat_in = lat_in*atan(1.0_kindl)/45.0_kindl
+
+        call horiz_interp_new(Hinterp,lon_in,lat_in, lon_local_out, lat_local_out, &
+            interp_method='bilinear')
+
+        deallocate(data_d_2d)
+        allocate(data_d_2d(isc:iec,jsc:jec))
+
+        time = set_date(1800,1,3,0,0,0)
+        data_d_2d = 0.0_kindl
+        call time_interp_external(id,time,data_d_2d,verbose=.true.,horz_interp=Hinterp)
+        sm = mpp_global_sum(domain,data_d_2d,flags=BITWISE_EXACT_SUM)
+        mx = mpp_global_max(domain,data_d_2d)
+        mn = mpp_global_min(domain,data_d_2d)
+        write(outunit,*) 'global sum= ', sm
+        write(outunit,*) 'global max= ', mx
+        write(outunit,*) 'global min= ', mn
+
+        sm = mpp_global_sum(domain,data_d_2d,flags=BITWISE_EXACT_SUM)
+        write(outunit,*) 'n valid points= ', sm
+
+        call horiz_interp_del(Hinterp)
+
+        deallocate(data_d_2d, data_g_2d, lon_local_out, lat_local_out, lon_in, lat_in)
+    end subroutine time_interpolate_2d_data
+
+    subroutine time_interpolate_scalar_data
+        real(TI_TEST_KIND_) :: data_scalar !< scalar to interpolate 
+
+        id = init_external_field(filename, fieldname,verbose=.false.)
+
+        !< Corresponds to time=1 in the file, so no time_interpolation
+        time = set_date(1800,1,2,0,0,0)
+        call time_interp_external(id,time,data_scalar,verbose=.true.)
+        print *, 'data= ', data_scalar
+
+        !< Corresponds to midpoint, so interpolation between 1 and 2 periods
+        time = set_date(1800,1,2,12,0,0)
+        call time_interp_external(id,time,data_scalar,verbose=.true.)
+        print *, 'data= ', data_scalar
+
+        !< Corresponds to time=2, so there will be time_interpolation between time=1 and
+        !time =3 in the file
+        time = set_date(1800,1,3,0,0,0)
+        call time_interp_external(id,time,data_scalar,verbose=.true.)
+        print *, 'data= ', data_scalar
+
+    end subroutine time_interpolate_scalar_data
+
+
 end program test_time_interp_external