Implements command line parser for the 3D mesher

fortran/meshfem3d/meshfem3D/CMakeLists.txt

@@ -31,6 +31,7 @@ set(MESHFEM3D_MESH_MODULE
     get_MPI_cutplanes_xi.f90
     meshfem3D.F90
     get_wavefield_discontinuity.f90
+    command_line_arguments.f90
     read_mesh_parameter_file.f90
     read_value_mesh_parameters.f90
     save_databases.F90

fortran/meshfem3d/shared/CMakeLists.txt

@@ -35,6 +35,7 @@ set(MESHFEM3D_SHARED_MODULE
   merge_sort.f90
   netlib_specfun_erf.f90
   prepare_assemble_MPI.f90
+  command_line_arguments.f90
   read_parameter_file.F90
   read_topo_bathy_file.f90
   read_value_parameters.f90

fortran/meshfem3d/shared/command_line_arguments.f90

@@ -0,0 +1,74 @@
+
+subroutine print_help_message()
+
+    implicit none
+
+    write(*,*) ' '
+    write(*,*) 'Usage: meshfem3D [options]'
+    write(*,*) ' '
+    write(*,*) 'Options:'
+    write(*,*) ' '
+    write(*,*) '  -h, --help'
+    write(*,*) '     Print this help message'
+    write(*,*) ' '
+    write(*,*) '  -p, --Par_File'
+    write(*,*) '     Specify the parameter file to use'
+    write(*,*) ' '
+
+end subroutine print_help_message
+
+subroutine parse_command_line_arguments()
+
+  use constants, only: MAX_STRING_LEN, one
+  use shared_parameters, only: Par_file
+
+  implicit none
+
+  integer :: i = 1, n_args
+
+  character(len=MAX_STRING_LEN) :: arg
+
+  ! get the number of command line arguments
+  n_args = command_argument_count()
+
+  if (n_args == 0) then
+    ! print help message
+    call print_help_message()
+    ! stop the code
+    stop
+  endif
+
+  ! loop over the command line arguments
+  do while(.TRUE.)
+    ! get the i-th command line argument
+    call get_command_argument(i, arg)
+
+    select case (arg)
+      case ('-h', '--help')
+        ! print help message
+        call print_help_message()
+        ! stop the code gracefully
+        call finalize_mpi()
+        call EXIT(0)
+      case ('-p', '--Par_File')
+        if (i == n_args) then
+          ! print error message
+          print *, 'Error: missing command line argument for option '//trim(arg)
+          stop
+        endif
+        ! get the next command line argument
+        call get_command_argument(i+1, Par_file)
+        ! skip the next command line argument
+        i = i + 1
+      case default
+        ! print error message
+        print *, 'Error: unknown command line argument '//trim(arg)
+        stop
+    end select
+
+    if (i == n_args) exit
+    ! increment the counter
+    i = i + 1
+  end do
+
+end subroutine parse_command_line_arguments

fortran/meshfem3d/shared/read_parameter_file.F90

@@ -44,6 +44,8 @@ subroutine read_parameter_file(BROADCAST_AFTER_READ)
   ! to avoid an I/O bottleneck in the case of very large runs
   if (myrank == 0) then
 
+    call parse_command_line_arguments()
+
     ! opens file Par_file
     call open_parameter_file(ier)
 

fortran/meshfem3d/shared/read_value_parameters.f90

@@ -157,34 +157,21 @@ end subroutine open_parameter_file_from_main_only
   subroutine open_parameter_file(ier)
 
   use constants, only: MAX_STRING_LEN,IN_DATA_FILES
+  use shared_input_parameters, only: Par_File
 
   implicit none
 
   integer :: ier
   character(len=MAX_STRING_LEN) :: filename_main,filename_run0001
 
-  filename_main = IN_DATA_FILES(1:len_trim(IN_DATA_FILES))//'Par_file'
-
-  ! note: for simultaneous runs, we require only a single Par_file in the main root directory DATA/Par_file
-  !       that is, no other files in the run directories are needed, like run0001/DATA/Par_file, run0001/DATA/Par_file, etc.
-  !       this avoids potential problems if different Par_files would have different settings (e.g., NPROC, MODEL, ..).
-
-  ! to be gentle, we also allow for a setup where the main Par_file is put into run0001/DATA/
-  ! in case we are running several independent runs in parallel
-  ! to do so, add the right directory for that run for the main process only here
-  filename_run0001 = 'run0001/'//filename_main(1:len_trim(filename_main))
+  filename_main = Par_File
 
   call param_open(filename_main, len(filename_main), ier)
+
   if (ier /= 0) then
     ! checks second option with Par_file in run0001/DATA/
-    call param_open(filename_run0001, len(filename_run0001), ier)
-    if (ier /= 0) then
-      print *
-      print *,'Opening file failed, please check your file path and run-directory.'
-      print *,'checked first: ',trim(filename_main)
-      print *,'     and then: ',trim(filename_run0001)
-      stop 'Error opening Par_file'
-    endif
+    print *, 'Error opening Par_file: ',trim(filename_main)
+    stop
   endif
 
   end subroutine open_parameter_file

fortran/meshfem3d/shared/shared_par.F90

@@ -108,6 +108,8 @@ module shared_input_parameters
 
   character(len=MAX_STRING_LEN) :: TOMOGRAPHY_PATH
 
+  character(len=MAX_STRING_LEN) :: Par_File
+
   ! attenuation
   ! reference frequency of seismic model
   double precision :: ATTENUATION_f0_REFERENCE