gd1.py

gd1.py

def test(xlist):
    # xlist is the list of the variables we have, and in this particular instance we have two variables     
    return 2*xlist[0]**2+3*xlist[0]*xlist[1]+5*xlist[1]**2

# functions
def partial_derivative(f, x_list, odr, epsilon = 1e-6, **kargs):
    # 此為模擬偏微分會有少量誤差
    h_list = x_list.copy()
    
    h_list[odr] = x_list[odr] + epsilon
    fx = f(x_list, **kargs)
    fh = f(h_list, **kargs)
    
    return (fh - fx) / epsilon 

def gradient(f, x_list, **kargs):
    grd = [partial_derivative(f, x_list, odr, **kargs) for odr in range(len(x_list))]
    return grd