From 316f75a857317bb67c6049d38dc26ca0cc54e5cd Mon Sep 17 00:00:00 2001
From: Valentin Sulzer <valentinsulzer@hotmail.com>
Date: Tue, 7 Apr 2020 15:32:37 -0400
Subject: [PATCH 1/3] #944 add automatic discretisation
---
pybamm/discretisations/discretisation.py | 3 +++
pybamm/models/base_model.py | 3 +++
pybamm/solvers/base_solver.py | 15 ++++++++++-----
3 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/pybamm/discretisations/discretisation.py b/pybamm/discretisations/discretisation.py
index 9a84cffd3e..1053080388 100644
--- a/pybamm/discretisations/discretisation.py
+++ b/pybamm/discretisations/discretisation.py
@@ -203,6 +203,9 @@ def process_model(self, model, inplace=True, check_model=True):
pybamm.logger.info("Finish discretising {}".format(model.name))
+ # Record that the model has been discretised
+ model_disc.is_discretised = True
+
return model_disc
def set_variable_slices(self, variables):
diff --git a/pybamm/models/base_model.py b/pybamm/models/base_model.py
index 84776f956c..3e6fdd9b7d 100644
--- a/pybamm/models/base_model.py
+++ b/pybamm/models/base_model.py
@@ -121,6 +121,9 @@ def __init__(self, name="Unnamed model"):
self.use_simplify = True
self.convert_to_format = "casadi"
+ # Model is not initially discretised
+ self.is_discretised = False
+
# Default timescale is 1 second
self.timescale = pybamm.Scalar(1)
diff --git a/pybamm/solvers/base_solver.py b/pybamm/solvers/base_solver.py
index 7549f887ba..6193349e18 100644
--- a/pybamm/solvers/base_solver.py
+++ b/pybamm/solvers/base_solver.py
@@ -128,6 +128,15 @@ def set_up(self, model, inputs=None):
raise pybamm.SolverError(
"""Cannot use algebraic solver to solve model with time derivatives"""
)
+ # Discretise model if it isn't already discretised
+ # This only works with purely 0D models, as otherwise the mesh and spatial
+ # method should be specified by the user
+ if model.is_discretised is False:
+ disc = pybamm.Discretisation()
+ disc.process_model(model)
+ # try:
+ # except error as e:
+ # raise ValueError(e)
inputs = inputs or {}
y0 = model.concatenated_initial_conditions.evaluate(0, None, inputs=inputs)
@@ -564,11 +573,7 @@ def solve(self, model, t_eval=None, external_variables=None, inputs=None):
]
# remove any discontinuities after end of t_eval
- discontinuities = [
- v
- for v in discontinuities
- if v < t_eval_dimensionless[-1]
- ]
+ discontinuities = [v for v in discontinuities if v < t_eval_dimensionless[-1]]
if len(discontinuities) > 0:
pybamm.logger.info(
From 157cf54967dc90a83eea620c35127dc24679d775 Mon Sep 17 00:00:00 2001
From: Valentin Sulzer <valentinsulzer@hotmail.com>
Date: Tue, 7 Apr 2020 15:42:10 -0400
Subject: [PATCH 2/3] #944 add test
---
pybamm/discretisations/discretisation.py | 7 +++++++
pybamm/expression_tree/exceptions.py | 8 +++++++
pybamm/solvers/base_solver.py | 13 +++++++-----
tests/unit/test_solvers/test_base_solver.py | 23 +++++++++++++++++++++
4 files changed, 46 insertions(+), 5 deletions(-)
diff --git a/pybamm/discretisations/discretisation.py b/pybamm/discretisations/discretisation.py
index 1053080388..3612df32b3 100644
--- a/pybamm/discretisations/discretisation.py
+++ b/pybamm/discretisations/discretisation.py
@@ -133,6 +133,13 @@ def process_model(self, model, inplace=True, check_model=True):
# Prepare discretisation
# set variables (we require the full variable not just id)
variables = list(model.rhs.keys()) + list(model.algebraic.keys())
+ if self.spatial_methods == {} and any(var.domain != [] for var in variables):
+ for var in variables:
+ if var.domain != []:
+ raise pybamm.DiscretisationError(
+ "Spatial method has not been given "
+ "for variable {} with domain {}".format(var.name, var.domain)
+ )
# Set the y split for variables
pybamm.logger.info("Set variable slices for {}".format(model.name))
diff --git a/pybamm/expression_tree/exceptions.py b/pybamm/expression_tree/exceptions.py
index d0f4341a20..41995623c6 100644
--- a/pybamm/expression_tree/exceptions.py
+++ b/pybamm/expression_tree/exceptions.py
@@ -67,3 +67,11 @@ class InputError(Exception):
"""
pass
+
+
+class DiscretisationError(Exception):
+ """
+ A model could not be discretised
+ """
+
+ pass
diff --git a/pybamm/solvers/base_solver.py b/pybamm/solvers/base_solver.py
index 6193349e18..e32c141045 100644
--- a/pybamm/solvers/base_solver.py
+++ b/pybamm/solvers/base_solver.py
@@ -132,11 +132,14 @@ def set_up(self, model, inputs=None):
# This only works with purely 0D models, as otherwise the mesh and spatial
# method should be specified by the user
if model.is_discretised is False:
- disc = pybamm.Discretisation()
- disc.process_model(model)
- # try:
- # except error as e:
- # raise ValueError(e)
+ try:
+ disc = pybamm.Discretisation()
+ disc.process_model(model)
+ except pybamm.DiscretisationError as e:
+ raise pybamm.DiscretisationError(
+ "Cannot automatically discretise model, "
+ "model should be discretised before solving ({})".format(e)
+ )
inputs = inputs or {}
y0 = model.concatenated_initial_conditions.evaluate(0, None, inputs=inputs)
diff --git a/tests/unit/test_solvers/test_base_solver.py b/tests/unit/test_solvers/test_base_solver.py
index ab051a9d06..3a7c2f130c 100644
--- a/tests/unit/test_solvers/test_base_solver.py
+++ b/tests/unit/test_solvers/test_base_solver.py
@@ -179,6 +179,29 @@ def algebraic_eval(self, t, y, inputs):
):
solver.calculate_consistent_state(Model())
+ def test_discretise_model(self):
+ # Make sure 0D model is automatically discretised
+ model = pybamm.BaseModel()
+ v = pybamm.Variable("v")
+ model.rhs = {v: -1}
+ model.initial_conditions = {v: 1}
+
+ solver = pybamm.BaseSolver()
+ self.assertFalse(model.is_discretised)
+ solver.set_up(model, {})
+ self.assertTrue(model.is_discretised)
+
+ # 1D model cannot be automatically discretised
+ model = pybamm.BaseModel()
+ v = pybamm.Variable("v", domain="line")
+ model.rhs = {v: -1}
+ model.initial_conditions = {v: 1}
+
+ with self.assertRaisesRegex(
+ pybamm.DiscretisationError, "Cannot automatically discretise model"
+ ):
+ solver.set_up(model, {})
+
def test_convert_to_casadi_format(self):
# Make sure model is converted to casadi format
model = pybamm.BaseModel()
From e6f98dfaefef4680f623c7e37e29268dd9728194 Mon Sep 17 00:00:00 2001
From: Valentin Sulzer <valentinsulzer@hotmail.com>
Date: Wed, 8 Apr 2020 10:26:31 -0400
Subject: [PATCH 3/3] #944 changelog [ci skip]
---
CHANGELOG.md | 1 +
1 file changed, 1 insertion(+)
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 324461980a..d1e646d411 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
## Features
+- Added functionality to solver to automatically discretise a 0D model ([#947](https://github.com/pybamm-team/PyBaMM/pull/947))
- Made `QuickPlot` compatible with Google Colab ([#935](https://github.com/pybamm-team/PyBaMM/pull/935))
- Added `BasicFull` model for lead-acid ([#932](https://github.com/pybamm-team/PyBaMM/pull/932))