Merge pull request #956 from pybamm-team/issue-853-casadi-safe

Issue 853 casadi safe

CHANGELOG.md

@@ -10,12 +10,14 @@
 
 ## Optimizations
 
+-   Changed the behaviour of "safe" mode in `CasadiSolver` ([#956](https://github.com/pybamm-team/PyBaMM/pull/956))
 -   Sped up model building ([#927](https://github.com/pybamm-team/PyBaMM/pull/927))
 -   Changed default solver for lead-acid to `CasadiSolver` ([#927](https://github.com/pybamm-team/PyBaMM/pull/927))
 
 ## Bug fixes
 
 -   Fixed `Interpolant` ids to allow processing ([#962](https://github.com/pybamm-team/PyBaMM/pull/962)
+-   Fixed a bug in the initial conditions of the potential pair model ([#954](https://github.com/pybamm-team/PyBaMM/pull/954))
 -   Changed simulation attributes to assign copies rather than the objects themselves ([#952](https://github.com/pybamm-team/PyBaMM/pull/952)
 -   Added default values to base model so that it works with the `Simulation` class ([#952](https://github.com/pybamm-team/PyBaMM/pull/952)
 -   Fixed solver to recompute initial conditions when inputs are changed ([#951](https://github.com/pybamm-team/PyBaMM/pull/951)

examples/notebooks/change-input-current.ipynb

@@ -53,7 +53,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "We can now solve the model in the ususal way, with a 16A current"
+    "We can now solve the model in the usual way, with a 1.6A current"
    ]
   },
   {
@@ -66,12 +66,12 @@
     {
      "data": {
       "application/vnd.jupyter.widget-view+json": {
-       "model_id": "8247adc1a3fd42dba31101bc6b501ed9",
+       "model_id": "807f6dec221b4226aea64326d51c751b",
        "version_major": 2,
        "version_minor": 0
       },
       "text/plain": [
-       "interactive(children=(FloatSlider(value=0.0, description='t', max=15.050167224080266, step=0.15050167224080266…"
+       "interactive(children=(FloatSlider(value=0.0, description='t', max=600.0, step=6.0), Output()), _dom_classes=('…"
       ]
      },
      "metadata": {},
@@ -92,9 +92,8 @@
     "\n",
     "# Solve the model at the given time points\n",
     "solver = pybamm.CasadiSolver()\n",
-    "n = 300\n",
-    "t_eval = np.linspace(0, 500, n)\n",
-    "solution = solver.solve(model, t_eval, inputs={\"Current function [A]\": 16})\n",
+    "t_eval = np.linspace(0, 600, 300)\n",
+    "solution = solver.solve(model, t_eval, inputs={\"Current function [A]\": 1.6})\n",
     "\n",
     "# plot\n",
     "quick_plot = pybamm.QuickPlot(solution)\n",
@@ -116,12 +115,12 @@
     {
      "data": {
       "application/vnd.jupyter.widget-view+json": {
-       "model_id": "511a6922f3f34350a543367723f09572",
+       "model_id": "eaab57697cef4852b4fbab5ee1f7efd7",
        "version_major": 2,
        "version_minor": 0
       },
       "text/plain": [
-       "interactive(children=(FloatSlider(value=0.0, description='t', max=500.0, step=5.0), Output()), _dom_classes=('…"
+       "interactive(children=(FloatSlider(value=0.0, description='t', max=600.0, step=6.0), Output()), _dom_classes=('…"
       ]
      },
      "metadata": {},
@@ -154,7 +153,7 @@
     {
      "data": {
       "application/vnd.jupyter.widget-view+json": {
-       "model_id": "def542dad39b4ddebcd9a555cf684580",
+       "model_id": "a72be467b6f84733927cb2e7a5c4b3f9",
        "version_major": 2,
        "version_minor": 0
       },
@@ -273,7 +272,7 @@
     {
      "data": {
       "application/vnd.jupyter.widget-view+json": {
-       "model_id": "7f4df64df94d410fb9aff92003538b14",
+       "model_id": "7dff98a2d9a44f87b71abeb0a94e16c9",
        "version_major": 2,
        "version_minor": 0
       },
@@ -330,9 +329,9 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.3"
+   "version": "3.6.9"
   }
  },
  "nbformat": 4,
  "nbformat_minor": 2
-}
+}

pybamm/models/submodels/current_collector/potential_pair.py

@@ -69,13 +69,12 @@ def set_algebraic(self, variables):
     def set_initial_conditions(self, variables):
 
         applied_current = self.param.current_with_time
-        cc_area = self._get_effective_current_collector_area()
         phi_s_cn = variables["Negative current collector potential"]
         i_boundary_cc = variables["Current collector current density"]
 
         self.initial_conditions = {
             phi_s_cn: pybamm.Scalar(0),
-            i_boundary_cc: applied_current / cc_area,
+            i_boundary_cc: applied_current,
         }
 
 

pybamm/solvers/base_solver.py

@@ -453,7 +453,7 @@ def solve(self, model, t_eval=None, external_variables=None, inputs=None):
             The model whose solution to calculate. Must have attributes rhs and
             initial_conditions
         t_eval : numeric type
-            The times at which to compute the solution
+            The times (in seconds) at which to compute the solution
         external_variables : dict
             A dictionary of external variables and their corresponding
             values at the current time
@@ -491,10 +491,6 @@ def solve(self, model, t_eval=None, external_variables=None, inputs=None):
         # Set up external variables and inputs
         ext_and_inputs = self._set_up_ext_and_inputs(model, external_variables, inputs)
 
-        # Make sure t_eval is monotonic
-        if (np.diff(t_eval) < 0).any():
-            raise pybamm.SolverError("t_eval must increase monotonically")
-
         # Set up
         timer = pybamm.Timer()
 
@@ -511,7 +507,6 @@ def solve(self, model, t_eval=None, external_variables=None, inputs=None):
 
         # Non-dimensionalise time
         t_eval_dimensionless = t_eval / model.timescale_eval
-        # Solve
 
         # Calculate discontinuities
         discontinuities = [
@@ -646,7 +641,7 @@ def step(
             The model whose solution to calculate. Must have attributes rhs and
             initial_conditions
         dt : numeric type
-            The timestep over which to step the solution
+            The timestep (in seconds) over which to step the solution
         npts : int, optional
             The number of points at which the solution will be returned during
             the step dt. default is 2 (returns the solution at t0 and t0 + dt).
@@ -708,10 +703,9 @@ def step(
 
         # Non-dimensionalise dt
         dt_dimensionless = dt / model.timescale_eval
+
         # Step
         t_eval = np.linspace(t, t + dt_dimensionless, npts)
-        # Set inputs and external
-
         pybamm.logger.info("Calling solver")
         timer.reset()
         solution = self._integrate(model, t_eval, ext_and_inputs)