pybamm-team#573 update with interpolating OCV functions, but it does …

…not work yet

results/LGM50/DFN.py

@@ -1,5 +1,7 @@
 import pybamm
 import numpy as np
+from scipy import interpolate
+import pandas as pd
 
 # load model
 model = pybamm.lithium_ion.DFN()
@@ -8,12 +10,32 @@
 geometry = model.default_geometry
 
 # load parameter values and process model and geometry
+def OCV_cathode(soc):
+    data = pd.read_csv("/home/ferranbrosa/PyBaMM/input/parameters/lithium-ion/nmc_LGM50_ocp_CC3.csv")
+    interpolated_OCV_cathode = interpolate.interp1d(
+        data.to_numpy()[:,0], 
+        data.to_numpy()[:,1], 
+        bounds_error=False, 
+        fill_value="extrapolate"
+    )
+    return float(interpolated_OCV_cathode(soc))
+
+def OCV_anode(sto):
+    data = pd.read_csv("/home/ferranbrosa/PyBaMM/input/parameters/lithium-ion/graphite_LGM50_ocp_CC3.csv")
+    interpolated_OCV_anode = interpolate.interp1d(
+        data.to_numpy()[:,0], 
+        data.to_numpy()[:,1], 
+        bounds_error=False, 
+        fill_value="extrapolate"
+    )
+    return float(interpolated_OCV_anode(sto))
+
 param = pybamm.ParameterValues("input/parameters/lithium-ion/LGM50_parameters.csv")
 param.update({
     "Electrolyte conductivity": "electrolyte_conductivity_Petibon2016.py",
     "Electrolyte diffusivity": "electrolyte_diffusivity_Stewart2008.py",
-    "Negative electrode OCV": "graphite_LGM50_ocp_CC3.py",
-    "Positive electrode OCV": "nmc_LGM50_ocp_CC3.py",
+    "Negative electrode OCV": OCV_anode,
+    "Positive electrode OCV": OCV_cathode,
     "Negative electrode diffusivity": "graphite_LGM50_diffusivity_CC3.py",
     "Positive electrode diffusivity": "nmc_LGM50_diffusivity_CC3.py",
     "Negative electrode OCV entropic change": "graphite_entropic_change_Moura.py",