Change mpi and taskfarm flags to use -- convention

gprMax/gprMax.py

@@ -231,13 +231,14 @@ def cli():
     parser.add_argument("-n", default=args_defaults["n"], type=int, help=help_msg["n"])
     parser.add_argument("-i", type=int, help=help_msg["i"])
     parser.add_argument(
-        "-taskfarm",
+        "--taskfarm",
+        "-t",
         action="store_true",
         default=args_defaults["taskfarm"],
         help=help_msg["taskfarm"],
     )
     parser.add_argument(
-        "-mpi",
+        "--mpi",
         type=int,
         action="store",
         nargs=3,

reframe_tests/tests/base_tests.py

@@ -451,7 +451,7 @@ class GprMaxMPIRegressionTest(GprMaxRegressionTest):
     def configure_test_run(self):
         """Add MPI specific commandline arguments"""
         self.num_tasks = int(prod(self.mpi_layout))
-        self.extra_executable_opts = ["-mpi", *map(str, self.mpi_layout)]
+        self.extra_executable_opts = ["--mpi", *map(str, self.mpi_layout)]
         super().configure_test_run()
 
     def _get_variant(self) -> str: