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   | import tensorflow as tf import numpy as np import matplotlib.pyplot as plt
  def add_layer(inputs, in_size, out_size, activation_function = None):     Weights = tf.Variable(tf.random_normal([in_size, out_size]))     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.initialize_all_variables() init = tf.global_variables_initializer()
  sess = tf.Session() sess.run(init)
  fig = plt.figure() ax = fig.add_subplot(1,1,1) ax.scatter(x_data,y_data)
  plt.ion() plt.show() # plt.close()
  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}))
          try:             ax.lines.remove(lines[0])         except Exception:             pass
          prediction_value = sess.run(prediction,feed_dict={xs:x_data})         lines = ax.plot(x_data,prediction_value,'r-',lw = 3)         plt.pause(0.5)
 
 
 
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