tensorflow学习之搭建最简单的神经网络

Posted 2022-01-06 yqpy

这几天在B站看莫烦的视频，学习一波，给出视频地址：https://www.bilibili.com/video/av16001891/?p=22

先放出代码

#####搭建神经网络测试
def add_layer(inputs,in_size,out_size,activation_function=None):
    Weights = tf.Variable(tf.random_normal([in_size, out_size],dtype=np.float32))
    biases = tf.Variable(tf.zeros([1,out_size])+0.1)
    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

x_data = np.linspace(-1,1,300)[:, np.newaxis]
noise = np.random.normal(0,0.05,x_data.shape)
y_data = np.square(x_data)-0.5+noise

xs = tf.placeholder(tf.float32,[None,1])
ys = tf.placeholder(tf.float32,[None,1])
l1 = add_layer(xs,1,10,activation_function=tf.nn.relu)

prediction = add_layer(l1,10,1,activation_function=None)
loss = tf.reduce_mean(tf.reduce_sum(tf.square(ys - prediction),
                                   reduction_indices=[1]))
train_step = tf.train.GradientDescentOptimizer(0.1).minimize(loss)

init = tf.global_variables_initializer()
with tf.Session() as sess:
    sess.run(init)
    for i in range(1000):
        sess.run(train_step,feed_dict=xs:x_data,ys:y_data)
        if i% 50 ==0:
            print(sess.run(loss,feed_dict=xs:x_data,ys:y_data))
#####

首先，在add_layer函数中，参数有inputs,in_size,out_size,activation_function=None

其中inupts是输入，in_size是输入维度，out_size是输出维度, activation_function是激活函数