import math def sumg(a1): z=0 for i in range(len(x)): z=z+(y[i]-g(a1,x[i]))*(y[i]-g(a1,x[i])) return z def g(a1,x1): f1=f(a,x1) g1=1/(1+math.exp(-f1)) return g1 def f(a1,x1): f1=a1[0] for i in range(len(x1)): f1=f1+a1[i+1]*x1[i] return f1 y=[0,0,0,1,1] x=[[1,2],[3,4],[5,6],[7,8],[9,10]] a=[0.1,0.2,0.3] print(sumg(a))