例子一、添加一个神经网络层
详见:https://morvanzhou.github.io/tutorials/machine-learning/tensorflow/3-1-add-layer/
import tensorflow as tf
def add_layer(inputs, input_size, output_size, activation_function = None):
Weights = tf.Variable(tf.random_normal([input_size, output_size]))
biases = tf.Variable(tf.zeros([1, output_size]) + 0.1) #biases初始化为0.1的列向量
Wx_plus_b = tf.matmul(inputs, Weights) + biases
if activation_function is None:
outputs = Wx_plus_b
else:
outputs = activation_function(Wx_plus_b)
return outputs
例子二:定义神经网络,神经网络包含输入层,隐藏层,输出层,输入层有784个节点,输出层有10个节点,隐藏层有500个节点
# 输入层 x = tf.placeholder(tf.float32, [None, 784]) y = tf.placeholder(tf.float32, [None, 10]) # ///////////////////隐藏层////////////////////// w1 = tf.Variable(tf.truncated_normal([784, 500], stddev=0.1)) b1 = tf.Variable(tf.zeros([500])) L1 = tf.nn.relu(tf.matmul(x, w1) + b1) w2 = tf.Variable(tf.truncated_normal([500, 300], stddev=0.1)) b2 = tf.Variable(tf.zeros([300])) L2 = tf.nn.relu(tf.matmul(L1, w2) + b2) # ///////////////////隐藏层////////////////////// # 输出层 w3 = tf.Variable(tf.truncated_normal([300, 10], stddev=0.1)) b3 = tf.Variable(tf.zeros([10])) prediction = tf.nn.softmax(tf.matmul(L2, w3)+b3)