Update IDAKLUSolver error handling (#5291)

* raise `SolverError` at failure to init sundials

* Update simulation.py

* Update idaklu_solver.py

* reuse `pybammsolvers` error messages

* Update test_idaklu_solver.py

* bump `pybammsolvers`

* Update CHANGELOG.md

* Update CHANGELOG.md

Update CHANGELOG.md

Author: MarcBerliner

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 ## Bug fixes
 
+- Fixed a bug where `IDAKLUSolver` errors were not raised correctly. ([#5291](https://github.com/pybamm-team/PyBaMM/pull/5291))
 - Fix a bug with serialising `InputParameter`s. ([#5289](https://github.com/pybamm-team/PyBaMM/pull/5289))
 
 # [v25.10.1](https://github.com/pybamm-team/PyBaMM/tree/v25.10.1) - 2025-11-14

pyproject.toml

@@ -25,7 +25,7 @@ classifiers = [
     "Topic :: Scientific/Engineering",
 ]
 dependencies = [
-    "pybammsolvers>=0.3.0,<0.4.0",
+    "pybammsolvers>=0.3.3,<0.4.0",
     "black",
     "numpy",
     "scipy>=1.11.4",

src/pybamm/simulation.py

@@ -822,7 +822,7 @@ def solve(
                             feasible = False
                             # If none of the cycles worked, raise an error
                             if cycle_num == 1 and step_num == 1:
-                                raise error
+                                raise error from error
                             # Otherwise, just stop this cycle
                             break
 

src/pybamm/solvers/idaklu_solver.py

@@ -684,13 +684,17 @@ def _integrate(
         atol = self._check_atol_type(atol, y0full.size)
 
         timer = pybamm.Timer()
-        solns = self._setup["solver"].solve(
-            t_eval,
-            t_interp,
-            y0full,
-            ydot0full,
-            inputs,
-        )
+        try:
+            solns = self._setup["solver"].solve(
+                t_eval,
+                t_interp,
+                y0full,
+                ydot0full,
+                inputs,
+            )
+        except ValueError as e:
+            # Return from None to replace the C++ runtime error
+            raise pybamm.SolverError(str(e)) from None
         integration_time = timer.time()
 
         return [
@@ -737,14 +741,15 @@ def _post_process_solution(self, sol, model, integration_time, inputs_dict):
             termination = "final time"
         elif sol.flag < 0:
             termination = "failure"
+            msg = idaklu.sundials_error_message(sol.flag)
             match self._on_failure:
                 case "warn":
                     warnings.warn(
-                        f"FAILURE {self._solver_flag(sol.flag)}, returning a partial solution.",
+                        msg + ", returning a partial solution.",
                         stacklevel=2,
                     )
                 case "raise":
-                    raise pybamm.SolverError(f"FAILURE {self._solver_flag(sol.flag)}")
+                    raise pybamm.SolverError(msg)
 
         if sol.yp.size > 0:
             yp = sol.yp.reshape((number_of_timesteps, number_of_states)).T
@@ -1005,40 +1010,3 @@ def jaxify(
             t_interp=t_interp,
         )
         return obj
-
-    @staticmethod
-    def _solver_flag(flag):
-        flags = {
-            99: "IDA_WARNING: IDASolve succeeded but an unusual situation occurred.",
-            2: "IDA_ROOT_RETURN: IDASolve succeeded and found one or more roots.",
-            1: "IDA_TSTOP_RETURN: IDASolve succeeded by reaching the specified stopping point.",
-            0: "IDA_SUCCESS: Successful function return.",
-            -1: "IDA_TOO_MUCH_WORK: The solver took mxstep internal steps but could not reach tout.",
-            -2: "IDA_TOO_MUCH_ACC: The solver could not satisfy the accuracy demanded by the user for some internal step.",
-            -3: "IDA_ERR_FAIL: Error test failures occurred too many times during one internal time step or minimum step size was reached.",
-            -4: "IDA_CONV_FAIL: Convergence test failures occurred too many times during one internal time step or minimum step size was reached.",
-            -5: "IDA_LINIT_FAIL: The linear solver's initialization function failed.",
-            -6: "IDA_LSETUP_FAIL: The linear solver's setup function failed in an unrecoverable manner.",
-            -7: "IDA_LSOLVE_FAIL: The linear solver's solve function failed in an unrecoverable manner.",
-            -8: "IDA_RES_FAIL: The user-provided residual function failed in an unrecoverable manner.",
-            -9: "IDA_REP_RES_FAIL: The user-provided residual function repeatedly returned a recoverable error flag, but the solver was unable to recover.",
-            -10: "IDA_RTFUNC_FAIL: The rootfinding function failed in an unrecoverable manner.",
-            -11: "IDA_CONSTR_FAIL: The inequality constraints were violated and the solver was unable to recover.",
-            -12: "IDA_FIRST_RES_FAIL: The user-provided residual function failed recoverably on the first call.",
-            -13: "IDA_LINESEARCH_FAIL: The line search failed.",
-            -14: "IDA_NO_RECOVERY: The residual function, linear solver setup function, or linear solver solve function had a recoverable failure, but IDACalcIC could not recover.",
-            -15: "IDA_NLS_INIT_FAIL: The nonlinear solver's init routine failed.",
-            -16: "IDA_NLS_SETUP_FAIL: The nonlinear solver's setup routine failed.",
-            -20: "IDA_MEM_NULL: The ida mem argument was NULL.",
-            -21: "IDA_MEM_FAIL: A memory allocation failed.",
-            -22: "IDA_ILL_INPUT: One of the function inputs is illegal.",
-            -23: "IDA_NO_MALLOC: The ida memory was not allocated by a call to IDAInit.",
-            -24: "IDA_BAD_EWT: Zero value of some error weight component.",
-            -25: "IDA_BAD_K: The k-th derivative is not available.",
-            -26: "IDA_BAD_T: The time t is outside the last step taken.",
-            -27: "IDA_BAD_DKY: The vector argument where derivative should be stored is NULL.",
-        }
-
-        flag_unknown = "Unknown IDA flag."
-
-        return flags.get(flag, flag_unknown)

tests/unit/test_solvers/test_idaklu_solver.py

@@ -583,7 +583,7 @@ def test_failures(self):
         solver = pybamm.IDAKLUSolver()
 
         t_eval = [0, 3]
-        with pytest.raises(ValueError):
+        with pytest.raises(pybamm.SolverError):
             solver.solve(model, t_eval)
 
     def test_dae_solver_algebraic_model(self):
@@ -779,7 +779,7 @@ def test_solver_options(self):
             options = {option: options_fail[option]}
             solver = pybamm.IDAKLUSolver(options=options)
 
-            with pytest.raises(ValueError):
+            with pytest.raises(pybamm.SolverError):
                 solver.solve(model, t_eval)
 
     def test_with_output_variables(self):
@@ -1487,7 +1487,7 @@ def test_on_failure_option(self):
                 model, t_eval=t_eval, t_interp=t_interp, inputs=input_parameters
             )
             assert len(w) > 0
-            assert "FAILURE" in str(w[0].message)
+            assert "_FAIL" in str(w[0].message)
 
     def test_no_progress_early_termination(self):
         # SPM at rest