functions.py

#!/usr/bin/env python3
# Version 2.2

import sys
import logging

class Functions:
        
    # Exception safe max and min (attention, not working with dictionaries)    
    # another option: res = [i for i in test_list if i is not None]
    
    def _max(self, x):
        try:
            return max(x)
        except Exception:
            return None
       
    def _min(self, x):
        try:
            return min(x)
        except Exception:
            return None
    
    # Interpolate f(x) if given lists Y = f(X)
          
    def _interpolate(self, X, Y, x):
        if len(X) == len(Y):
            _len = len(X)
            if x <= X[0]:
                return Y[0]
            elif x >= X[_len - 1]:
                return Y[_len - 1]
            else:
                for i in range(_len - 1):
                    if x <= X[i+1]:
                        return Y[i] + (Y[i+1] - Y[i]) / (X[i+1] - X[i]) * (x - X[i])        
        else:
            logging.error('Both lists must have the same length. Exiting.')
            sys.exit()
        

################        
# test program #
################
                    
def main(): 
    import settings as s
    fn = Functions()
    x = 2.51
    print(s.MAX_CHARGE_CURRENT*fn._interpolate(s.CELL_FULL_LIMITING_VOLTAGE, s.CELL_FULL_LIMITED_CURRENT, x))

if __name__ == "__main__":
	main()