Merge pull request #3186 from pybamm-team/issue-3185-fix_c_rate_drive…

…_cycle

Fix simulation with c_rate drive cycles

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 ## Bug fixes
 
+- Fix to simulate c_rate steps with drive cycles ([#3186](https://github.com/pybamm-team/PyBaMM/pull/3186))
 - Parameters in `Prada2013` have been updated to better match those given in the paper, which is a 2.3 Ah cell, instead of the mix-and-match with the 1.1 Ah cell from Lain2019.
 - Error generated when invalid parameter values are passed.
 - Thevenin() model is now constructed with standard variables: `Time [s], Time [min], Time [h]` ([#3143](https://github.com/pybamm-team/PyBaMM/pull/3143))

pybamm/simulation.py

@@ -291,8 +291,11 @@ def update_new_model_events(self, new_model, op):
                 # figure out whether the voltage event is greater than the starting
                 # voltage (charge) or less (discharge) and set the sign of the
                 # event accordingly
-                if isinstance(op.value, pybamm.Interpolant):
-                    sign = np.sign(op.value.y[0])
+                if (isinstance(op.value, pybamm.Interpolant) or
+                    isinstance(op.value, pybamm.Multiplication)):
+                    inpt = {"start time":0}
+                    init_curr = op.value.evaluate(t=0, inputs=inpt).flatten()[0]
+                    sign = np.sign(init_curr)
                 else:
                     sign = np.sign(op.value)
                 if sign > 0: