自己实现sigmoid、ReLU激活函数代码+图形

一、代码

1、numpy构建sigmoid函数

class Relu:
    def __init__(self):
        self.mask = None

    #向前传播
    def forward(self, x):
        self.mask = (x <= 0)
        out = x.copy()
        out[self.mask] = 0

        return out

    #反向传播
    def backward(self, dout):
        dout[self.mask] = 0
        dx = dout

        return dx

2、numpy构建ReLU激活函数 

class Sigmoid:
    def __init__(self):
        self.out = None

    #向前传播
    def forward(self,x):
        out = 1 / (1 + np.exp(-x))
        self.out = out
        return out
    
    #反向传播
    def backward(self,grad):
        dx = grad * (1.0 - self.out) * self.out
    
        return dx

二、图形