Adding ability to specify an input filename to the executable or to the python exec

include/openmc/initialize.h

@@ -1,6 +1,8 @@
 #ifndef OPENMC_INITIALIZE_H
 #define OPENMC_INITIALIZE_H
 
+#include <string>
+
 #ifdef OPENMC_MPI
 #include "mpi.h"
 #endif
@@ -19,6 +21,8 @@ void read_separate_xml_files();
 //! Write some output that occurs right after initialization
 void initial_output();
 
+
+std::string args_xml_filename {};
 } // namespace openmc
 
 #endif // OPENMC_INITIALIZE_H

openmc/executor.py

@@ -9,7 +9,7 @@ from .plots import _get_plot_image
 def _process_CLI_arguments(volume=False, geometry_debug=False, particles=None,
                            plot=False, restart_file=None, threads=None,
                            tracks=False, event_based=None,
-                           openmc_exec='openmc', mpi_args=None):
+                           openmc_exec='openmc', mpi_args=None, input_file=None):
     """Converts user-readable flags in to command-line arguments to be run with
     the OpenMC executable via subprocess.
 
@@ -42,6 +42,8 @@ def _process_CLI_arguments(volume=False, geometry_debug=False, particles=None,
     mpi_args : list of str, optional
         MPI execute command and any additional MPI arguments to pass,
         e.g. ['mpiexec', '-n', '8'].
+    input_file : str or Pathlike
+        Name of a single XML input file for the OpenMC executable to read.
 
     .. versionadded:: 0.13.0
 
@@ -82,6 +84,9 @@ def _process_CLI_arguments(volume=False, geometry_debug=False, particles=None,
     if mpi_args is not None:
         args = mpi_args + args
 
+    if input_file is not None:
+        args += ['-i', input_file]
+
     return args
 
 
@@ -118,7 +123,7 @@ def _run(args, output, cwd):
         raise RuntimeError(error_msg)
 
 
-def plot_geometry(output=True, openmc_exec='openmc', cwd='.'):
+def plot_geometry(output=True, openmc_exec='openmc', cwd='.', input_file=None):
     """Run OpenMC in plotting mode
 
     Parameters
@@ -129,6 +134,8 @@ def plot_geometry(output=True, openmc_exec='openmc', cwd='.'):
         Path to OpenMC executable
     cwd : str, optional
         Path to working directory to run in
+    input_file : str
+        Name of a single XML input file for the OpenMC executable to read.
 
     Raises
     ------
@@ -136,10 +143,13 @@ def plot_geometry(output=True, openmc_exec='openmc', cwd='.'):
         If the `openmc` executable returns a non-zero status
 
     """
+    args = [openmc_exec, '-p']
+    if input_file is not None:
+        args += ['-i', input_file]
     _run([openmc_exec, '-p'], output, cwd)
 
 
-def plot_inline(plots, openmc_exec='openmc', cwd='.'):
+def plot_inline(plots, openmc_exec='openmc', cwd='.', input_file=None):
     """Display plots inline in a Jupyter notebook.
 
     .. versionchanged:: 0.13.0
@@ -155,6 +165,8 @@ def plot_inline(plots, openmc_exec='openmc', cwd='.'):
         Path to OpenMC executable
     cwd : str, optional
         Path to working directory to run in
+    input_file : str
+        Name of a single XML input file for the OpenMC executable to read.
 
     Raises
     ------
@@ -171,7 +183,7 @@ def plot_inline(plots, openmc_exec='openmc', cwd='.'):
     openmc.Plots(plots).export_to_xml(cwd)
 
     # Run OpenMC in geometry plotting mode
-    plot_geometry(False, openmc_exec, cwd)
+    plot_geometry(False, openmc_exec, cwd, input_file)
 
     if plots is not None:
         images = [_get_plot_image(p, cwd) for p in plots]
@@ -179,7 +191,8 @@ def plot_inline(plots, openmc_exec='openmc', cwd='.'):
 
 
 def calculate_volumes(threads=None, output=True, cwd='.',
-                      openmc_exec='openmc', mpi_args=None):
+                      openmc_exec='openmc', mpi_args=None,
+                      input_file=None):
     """Run stochastic volume calculations in OpenMC.
 
     This function runs OpenMC in stochastic volume calculation mode. To specify
@@ -210,6 +223,8 @@ def calculate_volumes(threads=None, output=True, cwd='.',
     cwd : str, optional
         Path to working directory to run in. Defaults to the current working
         directory.
+    input_file : str or Pathlike
+        Name of a single XML input file for the OpenMC executable to read.
 
     Raises
     ------
@@ -223,14 +238,16 @@ def calculate_volumes(threads=None, output=True, cwd='.',
     """
 
     args = _process_CLI_arguments(volume=True, threads=threads,
-                                  openmc_exec=openmc_exec, mpi_args=mpi_args)
+                                  openmc_exec=openmc_exec, mpi_args=mpi_args,
+                                  input_file=input_file)
 
     _run(args, output, cwd)
 
 
 def run(particles=None, threads=None, geometry_debug=False,
         restart_file=None, tracks=False, output=True, cwd='.',
-        openmc_exec='openmc', mpi_args=None, event_based=False):
+        openmc_exec='openmc', mpi_args=None, event_based=False,
+        input_file=None):
     """Run an OpenMC simulation.
 
     Parameters
@@ -265,6 +282,9 @@ def run(particles=None, threads=None, geometry_debug=False,
 
         .. versionadded:: 0.12
 
+    input_file : str or Pathlike
+        Name of a single XML input file for the OpenMC executable to read.
+
     Raises
     ------
     RuntimeError
@@ -275,6 +295,7 @@ def run(particles=None, threads=None, geometry_debug=False,
     args = _process_CLI_arguments(
         volume=False, geometry_debug=geometry_debug, particles=particles,
         restart_file=restart_file, threads=threads, tracks=tracks,
-        event_based=event_based, openmc_exec=openmc_exec, mpi_args=mpi_args)
+        event_based=event_based, openmc_exec=openmc_exec, mpi_args=mpi_args,
+        input_file=input_file)
 
     _run(args, output, cwd)

openmc/model/model.py

@@ -221,7 +221,6 @@ class Model:
             Geometry object
 
         """
-
         if separate_xmls or not Path(path).exists():
             return cls.from_separate_xmls(*args, **kwargs)
         else:

src/initialize.cpp

@@ -181,10 +181,11 @@ int parse_command_line(int argc, char* argv[])
 
       } else if (arg == "-e" || arg == "--event") {
         settings::event_based = true;
-
+      } else if (arg == "-i" || arg == "--input") {
+        i += 1;
+        args_xml_filename = std::string(argv[i]);
       } else if (arg == "-r" || arg == "--restart") {
         i += 1;
-
         // Check what type of file this is
         hid_t file_id = file_open(argv[i], 'r', true);
         std::string filetype;
@@ -295,9 +296,19 @@ int parse_command_line(int argc, char* argv[])
 
 bool read_model_xml() {
   // get verbosity from settings node
-  std::string model_filename = settings::path_input + "model.xml";
-  bool use_model_file = file_exists(model_filename);
-  if (!file_exists(model_filename)) return false;
+
+  std::string xml_filename = "model.xml";
+  if (!args_xml_filename.empty()) xml_filename = args_xml_filename;
+  std::string model_filename = settings::path_input + xml_filename;
+
+  // check that the model file exists. If it does not and a custom filename was
+  // supplied by the user report an error
+  if (!file_exists(model_filename)) {
+    if (!args_xml_filename.empty()) {
+      fatal_error(fmt::format("The input file '{}' specified on the command line does not exist", args_xml_filename));
+    }
+    return false;
+  }
 
   // attempt to open the document
   pugi::xml_document doc;
@@ -325,6 +336,9 @@ bool read_model_xml() {
       title();
   }
 
+  if (!args_xml_filename.empty())
+  write_message(fmt::format("Reaging user-specified input '{}'...", args_xml_filename), 5);
+  else
   write_message("Reading model XML file...", 5);
 
   read_settings_xml(settings_root);

tests/regression_tests/model_xml/test.py

@@ -73,4 +73,24 @@ def test_model_xml(model, path, request):
     inputs = path + "/inputs_true.dat"
     results = path + "/results_true.dat"
     harness = ModelXMLTestHarness(request.getfixturevalue(model), inputs, results)
-    harness.main()
+    harness.main()
+
+def test_input_arg(run_in_tmpdir):
+
+    pincell = openmc.examples.pwr_pin_cell()
+
+    pincell.settings.particles = 100
+
+    # export to separate XML files and run
+    pincell.export_to_xml(separate_xmls=True)
+    openmc.run()
+
+    # now export to a single XML file with a custom name
+    pincell.export_to_xml(filename='pincell.xml', separate_xmls=False)
+
+    # run by specifying that single file
+    openmc.run(input_file='pincell.xml')
+
+    # now ensure we get an error for an incorrect filename
+    with pytest.raises(RuntimeError):
+        openmc.run(input_file='ex-em-ell.xml')