Convert PC Python objects into strings

petsctools/options.py

@@ -432,7 +432,10 @@ def __init__(self, parameters: dict,
         # Replace any Python objects in the parameters dict with appctx entries
         appmngr = AppContextManager()
         for key, value in parameters.items():
-            if not isinstance(value, _native_petsc_option_types):
+            # Convert Python PC objects into their string representation
+            if key.endswith("python_type") and isinstance(value, type):
+                parameters[key] = f"{value.__module__}.{value.__name__}"
+            elif not isinstance(value, _native_petsc_option_types):
                 parameters[key] = appmngr.add(value)
         self.appmngr = appmngr
 

tests/docs/test_appctx_docs.py

@@ -100,7 +100,7 @@ def test_appctx_docs():
             'ksp_converged_reason': None,
             'ksp_type': 'richardson',
             'pc_type': 'python',
-            'pc_python_type': f'{__name__}.DiffusionJacobiPC',
+            'pc_python_type': DiffusionJacobiPC,
             'djacobi_scale': 0.9,
             'djacobi_sigma': sigma_p,
         },

tests/test_options.py

@@ -182,7 +182,8 @@ def apply(self, pc, x, y):
 
 @pytest.mark.skipnopetsc4py
 @pytest.mark.parametrize("use_prefix", ["with_prefix", "without_prefix"])
-def test_appctx_context_manager(use_prefix):
+@pytest.mark.parametrize("use_pc_class", [False, True])
+def test_appctx_context_manager(use_prefix, use_pc_class):
     PETSc = petsctools.init()
     n = 4
     sizes = (n, n)
@@ -199,10 +200,14 @@ def test_appctx_context_manager(use_prefix):
     parameters = {
         'ksp_type': 'preonly',
         'pc_type': 'python',
-        'pc_python_type': f'{__name__}.JacobiTestPC',
         'jacobi_use_prefixed_appctx': use_prefix == "with_prefix",
         'jacobi_scale': diag,
     }
+    if use_pc_class:
+        parameters['pc_python_type'] = JacobiTestPC
+    else:
+        parameters['pc_python_type'] = f'{__name__}.JacobiTestPC'
+
     petsctools.set_from_options(
         ksp, parameters=parameters, options_prefix="myksp"
     )
@@ -219,6 +224,31 @@ def test_appctx_context_manager(use_prefix):
     assert (x - xcheck).norm() < 1e-14
 
 
+class MyPythonSNES:
+    pass
+
+
+@pytest.mark.skipnopetsc4py
+@pytest.mark.parametrize("use_prefix",
+                         [True, False],
+                         ids=["with_prefix", "without_prefix"])
+def test_python_type_option(use_prefix):
+    from petsc4py import PETSc
+
+    options = petsctools.OptionsManager(
+        parameters={
+            "snes_type": "python",
+            "snes_python_type": MyPythonSNES,
+        },
+        options_prefix="prefix_" if use_prefix else None
+    )
+
+    with options.inserted_options():
+        opts = PETSc.Options(options.options_prefix)
+        assert opts["snes_python_type"] == f"{__name__}.MyPythonSNES", \
+               "Python type name was not inserted into the options dictionary"
+
+
 @pytest.mark.skipnopetsc4py
 def test_python_options():
     petsctools.init()