1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
import numpy as np
class Variable:
def __init__(self, data):
self.data = data
class Function:
def __call__(self, input):
x = input.data
y = self.forward(x)
output = Variable(y)
self.input = input
self.output = output
return output
def forward(self, x):
raise NotImplementedError()
class Square(Function):
def forward(self, x):
return x ** 2
class Exp(Function):
def forward(self, x):
return np.exp(x)
def numerical_diff(f, x, eps=1e-4):
x0 = Variable(x.data - eps)
x1 = Variable(x.data + eps)
y0 = f(x0)
y1 = f(x1)
return (y1.data - y0.data) / (2 * eps)
f = Square()
x = Variable(np.array(2.0))
dy = numerical_diff(f, x)
print(dy)
def f(x):
A = Square()
B = Exp()
C = Square()
return C(B(A(x)))
x = Variable(np.array(0.5))
dy = numerical_diff(f, x)
print(dy)
|