import tensorflow as tf
sess = tf.InteractiveSession()

TensorFlow提供了7中激活函数

1.ReLU

$f(x)=max(x,0)$

print(tf.nn.relu(3.5).eval())
print(tf.nn.relu(-1).eval())
print(tf.nn.relu(7).eval())

3.5
0
7

2.ReLU6

$f(x)=min(max(x,0),6)$

print(tf.nn.relu6(3.5).eval())
print(tf.nn.relu6(-1).eval())
print(tf.nn.relu6(7).eval())

3.5
0
6

3.softplus

$f(x)=log(1+e^x)$

print(tf.nn.softplus(0.5).eval())

0.974077

4.sigmoid

$f(x)=\frac{1}{{1+e^{-x}}}$

print(tf.nn.sigmoid(2.0).eval())

0.880797

5.tanh

$f(x)=\frac{1-e^{-2x}}{1+e^{-2x}}$

print(tf.nn.tanh(2.0).eval())

0.9640276

6.bias_add

a = tf.constant([[1.0,1.0],[2.0,2.0],[3.0,3.0]])
b = tf.constant([1.0,1.0])
print(tf.nn.bias_add(a,b).eval())

[[2. 2.]
 [3. 3.]
 [4. 4.]]

7.dropout

x = tf.constant([[1.0,1.0],[2.0,2.0],[3.0,3.0]])
print(tf.nn.dropout(x,0.5).eval())

[[0. 0.]
 [0. 0.]
 [0. 6.]]