Add namelist and streams filename parameters to mpas_init (#10)

This alters the signature of the mpas_init subroutine in mpas_subdriver.F, adding two optional parameters that allow the caller to pass in filenames for the namelist and streams file. This allows the caller to specify different files to be used, other than namelist.atmosphere and streams.atmosphere in the working directory. This functionality is critical for several use-cases in MPAS-JEDI, including the ConvertState application, which interpolates data between two MPAS meshes of different resolutions.

src/driver/mpas_subdriver.F

@@ -39,7 +39,7 @@ module mpas_subdriver
    contains
 
 
-   subroutine mpas_init(corelist, domain_ptr, mpi_comm)
+   subroutine mpas_init(corelist, domain_ptr, mpi_comm, namelistFileParam, streamsFileParam)
 
       use mpas_stream_manager, only : MPAS_stream_mgr_init, MPAS_build_stream_filename, MPAS_stream_mgr_validate_streams
       use iso_c_binding, only : c_char, c_loc, c_ptr, c_int
@@ -53,7 +53,9 @@ subroutine mpas_init(corelist, domain_ptr, mpi_comm)
       type (core_type), intent(inout), pointer :: corelist
       type (domain_type), intent(inout), pointer :: domain_ptr
       integer, intent(in), optional :: mpi_comm
-
+      character(len=*), intent(in), optional :: namelistFileParam
+      character(len=*), intent(in), optional :: streamsFileParam
+
       integer :: iArg, nArgs
       logical :: readNamelistArg, readStreamsArg
       character(len=StrKIND) :: argument, namelistFile, streamsFile
@@ -109,6 +111,15 @@ end subroutine xml_stream_get_attributes
       readNamelistArg = .false.
       readStreamsArg = .false.
 
+      if (present(namelistFileParam) .and. len_trim(namelistFileParam) > 0 ) then
+         readNamelistArg = .true.
+         namelistFile = trim(namelistFileParam)
+      endif
+      if (present(streamsFileParam)  .and. len_trim(streamsFileParam) > 0 ) then
+         readStreamsArg = .true.
+         streamsFile = trim(streamsFileParam)
+      endif
+
       nArgs = command_argument_count()
       iArg = 1
       do while (iArg < nArgs)