#920 tino comments

CHANGELOG.md

@@ -42,6 +42,7 @@
 
 ## Breaking changes
 
+-   Calls to `ProcessedVariable` objects are now made using dimensional time and space ([#1028](https://github.com/pybamm-team/PyBaMM/pull/1028))
 -   For variables discretised using finite elements the result returned by calling `ProcessedVariable` is now transposed ([#1020](https://github.com/pybamm-team/PyBaMM/pull/1020))
 -   Renamed "surface area density" to "surface area to volume ratio" ([#975](https://github.com/pybamm-team/PyBaMM/pull/975))
 -   Replaced "reaction rate" with "exchange-current density" ([#975](https://github.com/pybamm-team/PyBaMM/pull/975))

examples/notebooks/compare-comsol-discharge-curve.ipynb

@@ -146,7 +146,7 @@
     "    # solve model at comsol times\n",
     "    solver = pybamm.CasadiSolver(mode=\"fast\")\n",
     "    solution = solver.solve(model, comsol_time, inputs={\"Current function [A]\": current})\n",
-    "    time_in_seconds = solution.t * model.timescale_eval\n",
+    "    time_in_seconds = solution[\"Time [s]\"].entries\n",
     "    # discharge capacity\n",
     "    discharge_capacity = solution[\"Discharge capacity [A.h]\"]\n",
     "    discharge_capacity_sol = discharge_capacity(time_in_seconds)\n",

examples/notebooks/rate-capability.ipynb

@@ -18,7 +18,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 1,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -36,7 +36,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 2,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -52,7 +52,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 10,
+   "execution_count": 3,
    "metadata": {},
    "outputs": [
     {

examples/scripts/DFN.py

@@ -30,9 +30,7 @@
 
 # solve model
 t_eval = np.linspace(0, 3600, 100)
-solver = pybamm.CasadiSolver()
-solver.rtol = 1e-3
-solver.atol = 1e-6
+solver = pybamm.CasadiSolver(atol=1e-3, rtol=1e-6)
 solution = solver.solve(model, t_eval)
 
 # plot

examples/scripts/DFN_ambient_temperature.py

@@ -40,9 +40,7 @@ def ambient_temperature(t):
 
 # solve model
 t_eval = np.linspace(0, 3600 / 2, 100)
-solver = pybamm.CasadiSolver(mode="fast")
-solver.rtol = 1e-3
-solver.atol = 1e-6
+solver = pybamm.CasadiSolver(mode="fast", atol=1e-3, rtol=1e-3)
 solution = solver.solve(model, t_eval)
 
 # plot

examples/scripts/SPMe_SOC.py

@@ -85,7 +85,7 @@
         xnsurf = sol["X-averaged negative particle surface concentration"]
         time = sol["Time [h]"]
         # Coulomb counting
-        time_secs = sol.t * model.timescale_eval
+        time_secs = sol["Time [s]"].entries
         time_hours = time(time_secs)
         dc_time = np.around(time_hours[-1], 3)
         # Capacity mAh

examples/scripts/SPMe_step.py

@@ -42,20 +42,12 @@
     time += dt
 
 # plot
-voltage = solution["Terminal voltage [V]"]
-step_voltage = step_solution["Terminal voltage [V]"]
-plt.plot(
-    solution.t * timescale,
-    voltage(solution.t * timescale),
-    "b-",
-    label="SPMe (continuous solve)",
-)
-plt.plot(
-    step_solution.t * timescale,
-    step_voltage(step_solution.t * timescale),
-    "ro",
-    label="SPMe (stepped solve)",
-)
+time_in_seconds = solution["Time [s]"].entries
+step_time_in_seconds = step_solution["Time [s]"].entries
+voltage = solution["Terminal voltage [V]"].entries
+step_voltage = step_solution["Terminal voltage [V]"].entries
+plt.plot(time_in_seconds, voltage, "b-", label="SPMe (continuous solve)")
+plt.plot(step_time_in_seconds, step_voltage, "ro", label="SPMe (stepped solve)")
 plt.xlabel(r"$t$")
 plt.ylabel("Terminal voltage [V]")
 plt.legend()

examples/scripts/compare_comsol/discharge_curve.py

@@ -64,7 +64,7 @@
     solution = pybamm.CasadiSolver(mode="fast").solve(
         model, t, inputs={"Current function [A]": current}
     )
-    time_in_seconds = solution.t * model.timescale_eval
+    time_in_seconds = solution["Time [s]"].entries
 
     # discharge capacity
     discharge_capacity = solution["Discharge capacity [A.h]"]

examples/scripts/compare_lithium_ion_3D.py → examples/scripts/compare_lithium_ion_2D.py

@@ -18,11 +18,11 @@
 # load models
 models = [
     pybamm.lithium_ion.SPM(
-        {"current collector": "potential pair", "dimensionality": 2}, name="2+1D SPM"
+        {"current collector": "potential pair", "dimensionality": 1}, name="2+1D SPM"
+    ),
+    pybamm.lithium_ion.SPMe(
+        {"current collector": "potential pair", "dimensionality": 1}, name="2+1D SPMe"
     ),
-    # pybamm.lithium_ion.SPMe(
-    #     {"current collector": "potential pair", "dimensionality": 2}, name="2+1D SPMe"
-    # ),
 ]
 
 # load parameter values and process models
@@ -36,13 +36,13 @@
     param.process_geometry(geometry)
     var = pybamm.standard_spatial_vars
     var_pts = {
-        var.x_n: 5,
-        var.x_s: 5,
-        var.x_p: 5,
-        var.r_n: 5,
-        var.r_p: 5,
-        var.y: 5,
-        var.z: 5,
+        var.x_n: 10,
+        var.x_s: 10,
+        var.x_p: 10,
+        var.r_n: 10,
+        var.r_p: 10,
+        var.y: 10,
+        var.z: 10,
     }
     mesh = pybamm.Mesh(geometry, model.default_submesh_types, var_pts)
     disc = pybamm.Discretisation(mesh, model.default_spatial_methods)
@@ -56,6 +56,10 @@
     solutions[i] = solution
 
 # plot
-output_variables = ["Terminal voltage [V]", "Negative current collector potential [V]"]
+output_variables = [
+    "Terminal voltage [V]",
+    "Negative current collector potential [V]",
+    "Positive current collector potential [V]",
+]
 plot = pybamm.QuickPlot(solutions, output_variables)
 plot.dynamic_plot()

examples/scripts/rate_capability.py

@@ -21,13 +21,14 @@
     sim = pybamm.Simulation(model, experiment=experiment, solver=pybamm.CasadiSolver())
     sim.solve()
 
+    time = sim.solution["Time [s]"].entries
     capacity = sim.solution["Discharge capacity [A.h]"]
     current = sim.solution["Current [A]"]
     voltage = sim.solution["Terminal voltage [V]"]
 
-    capacities[i] = capacity(sim.solution.t[-1])
-    currents[i] = current(sim.solution.t[-1])
-    voltage_av[i] = np.mean(voltage(sim.solution.t))
+    capacities[i] = capacity(time[-1])
+    currents[i] = current(time[-1])
+    voltage_av[i] = np.mean(voltage(time))
 
 plt.figure(1)
 plt.scatter(C_rates, capacities)

pybamm/models/submodels/current_collector/effective_resistance_current_collector.py

@@ -40,9 +40,6 @@ def __init__(
         self.options = options
         self.param = pybamm.standard_parameters_lithium_ion
 
-        # Default timescale is discharge timescale (used in post process)
-        self.timescale = self.param.tau_discharge
-
         self.variables = self.get_fundamental_variables()
         self.set_algebraic(self.variables)
         self.set_boundary_conditions(self.variables)

pybamm/solvers/processed_variable.py

@@ -60,18 +60,17 @@ def __init__(self, base_variable, solution, known_evals=None, warn=True):
         self.warn = warn
 
         # Set timescale
-        try:
-            self.timescale = solution.model.timescale_eval
-        except AttributeError:
-            if self.warn:
-                pybamm.logger.warning("No timescale provided. Using default of 1 [s]")
-            self.timescale = 1
+        self.timescale = solution.model.timescale_eval
+        self.t_pts = self.t_sol * self.timescale
 
         # Store spatial variables to get scales
         self.spatial_vars = {}
         if solution.model:
             for var in ["x", "y", "z", "r_n", "r_p"]:
-                if var and var + " [m]" in solution.model.variables:
+                if (
+                    var in solution.model.variables
+                    and var + " [m]" in solution.model.variables
+                ):
                     self.spatial_vars[var] = solution.model.variables[var]
                     self.spatial_vars[var + " [m]"] = solution.model.variables[
                         var + " [m]"
@@ -156,7 +155,7 @@ def fun(t):
             self._interpolation_function = fun
         else:
             self._interpolation_function = interp.interp1d(
-                self.t_sol * self.timescale,
+                self.t_pts,
                 entries,
                 kind="linear",
                 fill_value=np.nan,
@@ -250,7 +249,7 @@ def interp_fun(t, z):
             # function of space and time. Note that the order of 't' and 'space'
             # is the reverse of what you'd expect
             self._interpolation_function = interp.interp2d(
-                self.t_sol * self.timescale,
+                self.t_pts,
                 self.first_dim_pts,
                 entries_for_interp,
                 kind="linear",
@@ -353,7 +352,7 @@ def interp_fun(input):
         else:
             # function of space and time.
             self._interpolation_function = interp.RegularGridInterpolator(
-                (self.first_dim_pts, self.second_dim_pts, self.t_sol * self.timescale),
+                (self.first_dim_pts, self.second_dim_pts, self.t_pts),
                 entries,
                 method="linear",
                 fill_value=np.nan,
@@ -418,7 +417,7 @@ def interp_fun(input):
         else:
             # function of space and time.
             self._interpolation_function = interp.RegularGridInterpolator(
-                (self.first_dim_pts, self.second_dim_pts, self.t_sol * self.timescale),
+                (self.first_dim_pts, self.second_dim_pts, self.t_pts),
                 entries,
                 method="linear",
                 fill_value=np.nan,
@@ -436,10 +435,10 @@ def __call__(self, t=None, x=None, r=None, y=None, z=None, warn=True):
         # time) evaluate arbitrarily at the first value of t. Otherwise, raise
         # an error
         if t is None:
-            if len(self.t_sol) == 1:
-                t = self.t_sol * self.timescale
+            if len(self.t_pts) == 1:
+                t = self.t_pts
             elif self.base_variable.is_constant():
-                t = self.t_sol[0] * self.timescale
+                t = self.t_pts[0]
             else:
                 raise ValueError(
                     "t cannot be None for variable {}".format(self.base_variable)

pybamm/solvers/solution.py

@@ -50,7 +50,7 @@ def __init__(
         if copy_this is None:
             # initialize empty inputs and model, to be populated later
             self._inputs = pybamm.FuzzyDict()
-            self._model = None
+            self._model = pybamm.BaseModel()
             self.set_up_time = None
             self.solve_time = None
             self.has_symbolic_inputs = False

tests/unit/test_solvers/test_solution.py

@@ -20,7 +20,7 @@ def test_init(self):
         self.assertEqual(sol.y_event, None)
         self.assertEqual(sol.termination, "final time")
         self.assertEqual(sol.inputs, {})
-        self.assertEqual(sol.model, None)
+        self.assertIsInstance(sol.model, pybamm.BaseModel)
 
         with self.assertRaisesRegex(AttributeError, "sub solutions"):
             print(sol.sub_solutions)