Made Controller more resilient

pde/solvers/controller.py

@@ -163,7 +163,7 @@ def _run_main_process(self, state: TState, dt: float | None = None) -> None:
         # initialize solver information
         self.info["t_start"] = t_start
         self.info["t_end"] = t_end
-        self.diagnostics["solver"] = self.solver.info
+        self.diagnostics["solver"] = getattr(self.solver, "info", {})
 
         # initialize profilers
         jit_count_base = int(JIT_COUNT)
@@ -187,7 +187,8 @@ def _run_main_process(self, state: TState, dt: float | None = None) -> None:
         self.info["solver_start"] = str(solver_start)
 
         if dt is None:
-            dt = self.solver.info.get("dt")
+            # use self.solver.info['dt'] if it is present
+            dt = self.diagnostics["solver"].get("dt")
         # add some tolerance to account for inaccurate float point math
         if dt is None:  # self.solver.info['dt'] might be None
             atol = 1e-12
@@ -256,7 +257,7 @@ def _run_main_process(self, state: TState, dt: float | None = None) -> None:
         self.info["t_final"] = t
         self.info["jit_count"]["simulation"] = int(JIT_COUNT) - jit_count_after_init
         self.trackers.finalize(info=self.diagnostics)
-        if "dt_statistics" in self.solver.info:
+        if "dt_statistics" in getattr(self.solver, "info", {}):
             dt_statistics = dict(self.solver.info["dt_statistics"].to_dict())
             self.solver.info["dt_statistics"] = dt_statistics
 
@@ -396,7 +397,7 @@ def run(self, initial_state: TState, dt: float | None = None) -> TState | None:
         from ..tools import mpi
 
         # copy the initial state to not modify the supplied one
-        if hasattr(self.solver, "pde") and self.solver.pde.complex_valued:
+        if getattr(self.solver, "pde", None) and self.solver.pde.complex_valued:
             self._logger.info("Convert state to complex numbers")
             state: TState = initial_state.copy(dtype=complex)
         else:

tests/solvers/test_controller.py

@@ -3,8 +3,10 @@
 """
 
 import pytest
+import numpy as np
 
 from pde import PDEBase, ScalarField, UnitGrid
+from pde.solvers import Controller
 
 
 def test_controller_abort():
@@ -27,3 +29,18 @@ def evolution_rate(self, state, t):
 
     assert eq.diagnostics["last_tracker_time"] >= 0
     assert eq.diagnostics["last_state"] == field
+
+
+def test_controller_foreign_solver():
+    """Test whether the Controller can deal with a minimal foreign solver"""
+
+    class MySolver:
+        def make_stepper(self, state, dt):
+            def stepper(state, t, t_break):
+                return t_break
+
+            return stepper
+
+    c = Controller(MySolver(), t_range=1)
+    res = c.run(np.arange(3))
+    np.testing.assert_allclose(res, np.arange(3))