Uninformative error message in update: "Matrix is singular."

[eivindjahren]

This behavior can be reproduced with this setup: https://github.com/eivindjahren/ert/tree/update_err_msgs/test-data/ert/counter_examples/matrix-is-singular-0

This is the traceback of the thrown error:

Traceback (most recent call last):
  File "/../ert/src/ert/gui/simulation/run_dialog.py", line 426, in _on_event
    @Slot(object)

  File "/../ert/src/_ert/threading.py", line 85, in _handler
    raise current_exception
_ert.threading.ErtThreadError: Matrix is singular. in thread 'ert_gui_simulation_thread'
 Traceback (most recent call last):
  File "/../ert/src/_ert/threading.py", line 57, in run
    super().run()
  File "/.../opentelemetry/instrumentation/threading/__init__.py", line 129, in __wrap_threading_run
    return call_wrapped(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/threading.py", line 1010, in run
    self._target(*self._args, **self._kwargs)
  File "/../ert/src/ert/gui/simulation/run_dialog.py", line 354, in run
    self._run_model.start_simulations_thread(
  File "/usr/lib/python3.12/contextlib.py", line 81, in inner
    return func(*args, **kwds)
           ^^^^^^^^^^^^^^^^^^^
  File "/../ert/src/ert/run_models/base_run_model.py", line 355, in start_simulations_thread
    raise e
  File "/../ert/src/ert/run_models/base_run_model.py", line 331, in start_simulations_thread
    self.run_experiment(
  File "/usr/lib/python3.12/contextlib.py", line 81, in inner
    return func(*args, **kwds)
           ^^^^^^^^^^^^^^^^^^^
  File "/../ert/src/ert/run_models/ensemble_smoother.py", line 98, in run_experiment
    posterior = self.update(prior, ensemble_format % 1)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/../ert/src/ert/run_models/base_run_model.py", line 792, in update
    smoother_update(
  File "/../ert/src/ert/analysis/_es_update.py", line 798, in smoother_update
    raise e
  File "/../ert/src/ert/analysis/_es_update.py", line 772, in smoother_update
    analysis_ES(
  File "/../ert/src/ert/analysis/_es_update.py", line 518, in analysis_ES
    T = smoother_es.compute_transition_matrix(Y=S, alpha=1.0, truncation=truncation)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/.../iterative_ensemble_smoother/esmda.py", line 350
, in compute_transition_matrix
    return inversion_func(
           ^^^^^^^^^^^^^^^
  File "/.../iterative_ensemble_smoother/esmda_inversion.py"
, line 229, in inversion_exact_cholesky
    T = sp.linalg.solve(C_DD, D - Y, **solver_kwargs)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/.../scipy/linalg/_basic.py", line 253, in solve
    _solve_check(n, info)
  File "/.../scipy/linalg/_basic.py", line 40, in _solve_che
ck
    raise LinAlgError('Matrix is singular.')