Structured Output Prediction (Baseline NN ) の実装に関するメモ

##ポイント
* Baseline Neural Network を実装し、具体的な数値で確認。

##レファレンス
[1. Learning Structured Output Representation using Deep Conditional Generative Models](https://pdfs.semanticscholar.org/3f25/e17eb717e5894e0404ea634451332f85d287.pdf)

##サンプルコード
```python
class BaseLine():
  
  def __init__(self):
    pass
  
  def weight_variable(self, name, shape):
    initializer = tf.truncated_normal_initializer(mean = 0.0, stddev = 0.01, dtype = tf.float32)
    return tf.get_variable(name, shape, initializer = initializer)
  
  def bias_variable(self, name, shape):
    initializer = tf.constant_initializer(value = 0.0, dtype = tf.float32)
    return tf.get_variable(name, shape, initializer = initializer)

  def const_zero(self, name, shape):
    initializer = tf.constant_initializer(value = 0.0, dtype = tf.float32)
    return tf.get_variable(name, shape, initializer = initializer)

  def const_one(self, name, shape):
    initializer = tf.constant_initializer(value = 1.0, dtype = tf.float32)
    return tf.get_variable(name, shape, initializer = initializer)

  def inference(self, x, n_in, n_units_1, n_units_2, n_out):
    with tf.variable_scope('mlp'):
      w_1 = self.weight_variable('w_1', [n_in, n_units_1])
      b_1 = self.bias_variable('b_1', [n_units_1])
      
      h_1 = tf.add(tf.matmul(x, w_1), b_1)

      # batch normalization
      beta_1 = self.const_zero('beta_1', [n_units_1])
      gamma_1 = self.const_one('gamma_1', [n_units_1])
      
      mean_1, var_1 = tf.nn.moments(h_1, [0])
      h_1 = gamma_1 * (h_1 - mean_1) / tf.sqrt(var_1 + 1e-5) + beta_1
      
      bn_1 = tf.nn.sigmoid(h_1)
      
      w_2 = self.weight_variable('w_2', [n_units_1, n_units_2])
      b_2 = self.bias_variable('b_2', [n_units_2])

      h_2 = tf.add(tf.matmul(bn_1, w_2), b_2)
      
      # batch normalization
      beta_2 = self.const_zero('beta_2', [n_units_2])
      gamma_2 = self.const_one('gamma_2', [n_units_2])
      
      mean_2, var_2 = tf.nn.moments(h_2, [0])
      h_2 = gamma_2 * (h_2 - mean_2) / tf.sqrt(var_2 + 1e-5) + beta_2
      
      bn_2 = tf.nn.sigmoid(h_2)
      
      w_3 = self.weight_variable('w_3', [n_units_2, n_out])
      b_3 = self.bias_variable('b_3', [n_out])

      h_3 = tf.add(tf.matmul(bn_2, w_3), b_3)
      
      return tf.nn.sigmoid(h_3)
    
  def loss(self, y, t):
    return - tf.reduce_mean(tf.reduce_sum(t * tf.log(tf.clip_by_value(y, 1e-10, 1.0)) + \
                                                             (1 - t) * tf.log(tf.clip_by_value(1 - y, 1e-10, 1.0)), axis = 1))
    #return tf.reduce_mean(tf.square(t - y))
    
  def training(self, loss, learning_rate):
    optimizer = tf.train.AdamOptimizer(learning_rate = learning_rate)
    train_step = optimizer.minimize(loss)
    return train_step
  
  def training_clipped(self, loss, learning_rate, clip_norm):
    optimizer = tf.train.AdamOptimizer(learning_rate = learning_rate)

    grads_and_vars = optimizer.compute_gradients(loss)
    clipped_grads_and_vars = [(tf.clip_by_norm(grad, clip_norm = clip_norm), \
                             var) for grad, var in grads_and_vars]
    train_step = optimizer.apply_gradients(clipped_grads_and_vars)
    
    return train_step

  def fit(self, images_train_x, images_train_y, labels_train, images_test_x, images_test_y, labels_test, \
          n_in, n_units_1, n_units_2, n_out, \
          learning_rate, n_iter, batch_size, show_step, is_saving, model_path):
    
    tf.reset_default_graph()
    
    x = tf.placeholder(shape = [None, 14 * 28], dtype = tf.float32)
    t = tf.placeholder(shape = [None, 14 * 28], dtype = tf.float32)
    
    y = self.inference(x, n_in, n_units_1, n_units_2, n_out)
    loss = self.loss(y, t)
    train_step = self.training(loss, learning_rate)
    
    init = tf.global_variables_initializer()
    saver = tf.train.Saver()
    
    with tf.Session() as sess:
      
      sess.run(init)
      
      history_loss_train = []
      history_loss_test = []
      
      for i in range(n_iter):
        # Train
        rand_index = np.random.choice(len(images_train_x), size = batch_size)
        x_batch = images_train_x[rand_index]
        y_batch = images_train_y[rand_index]
        
        feed_dict = {x: x_batch, t: y_batch}

        sess.run(train_step, feed_dict = feed_dict)

        temp_loss = sess.run(loss, feed_dict = feed_dict)
        history_loss_train.append(temp_loss)

        if (i + 1) % show_step == 0:
          print ('--------------------')
          print ('Iteration: ' + str(i + 1) + '  Loss: ' + str(temp_loss))
          
        # Test
        rand_index = np.random.choice(len(images_test_x), size = batch_size)
        x_batch = images_test_x[rand_index]
        y_batch = images_test_y[rand_index]
        
        feed_dict = {x: x_batch, t: y_batch}

        temp_loss = sess.run(loss, feed_dict = feed_dict)
        history_loss_test.append(temp_loss)

      if is_saving:
        model_path = saver.save(sess, model_path)
        print ('--------------------')
        print ('done saving at ', model_path)

    fig = plt.figure(figsize = (10, 3))
    ax1 = fig.add_subplot(1, 2, 1)
    ax1.plot(range(n_iter), history_loss_train, 'b-', label = 'Train')
    ax1.plot(range(n_iter), history_loss_test, 'r--', label = 'Test')
    ax1.set_title('Loss')
    ax1.legend(loc = 'upper right')

    plt.show()    
  
  def prediction(self, x, n_in, n_units_1, n_units_2, n_out, model_path):
    with tf.variable_scope('mlp', reuse = True):
      w_1 = self.weight_variable('w_1', [n_in, n_units_1])
      b_1 = self.bias_variable('b_1', [n_units_1])
      
      h_1 = tf.add(tf.matmul(x, w_1), b_1)

      # batch normalization
      beta_1 = self.const_zero('beta_1', [n_units_1])
      gamma_1 = self.const_one('gamma_1', [n_units_1])
      
      mean_1, var_1 = tf.nn.moments(h_1, [0])
      h_1 = gamma_1 * (h_1 - mean_1) / tf.sqrt(var_1 + 1e-5) + beta_1
      
      bn_1 = tf.nn.sigmoid(h_1)
      
      w_2 = self.weight_variable('w_2', [n_units_1, n_units_2])
      b_2 = self.bias_variable('b_2', [n_units_2])

      h_2 = tf.add(tf.matmul(bn_1, w_2), b_2)
      
      # batch normalization
      beta_2 = self.const_zero('beta_2', [n_units_2])
      gamma_2 = self.const_one('gamma_2', [n_units_2])
      
      mean_2, var_2 = tf.nn.moments(h_2, [0])
      h_2 = gamma_2 * (h_2 - mean_2) / tf.sqrt(var_2 + 1e-5) + beta_2
      
      bn_2 = tf.nn.sigmoid(h_2)
      
      w_3 = self.weight_variable('w_3', [n_units_2, n_out])
      b_3 = self.bias_variable('b_3', [n_out])

      h_3 = tf.add(tf.matmul(bn_2, w_3), b_3)
      
      y = tf.nn.sigmoid(h_3)

    saver = tf.train.Saver()
    
    with tf.Session() as sess:
      
      saver.restore(sess, model_path)
    
      return sess.run(y)
```

##データ
```python
images_train_x = mnist.train.images[:, :14*28]
images_train_y = mnist.train.images[:, 14*28:]
labels_train = mnist.train.labels
images_test_x = mnist.test.images[:, :14*28]
images_test_y = mnist.test.images[:, 14*28:]
labels_test = mnist.test.labels
```

##パラメータ
n_in = 14*28
n_units_1 = 64
n_units_2 = 64
n_out = 14*28
learning_rate = 0.01
batch_size = 100 

##アウトプット
![image.png](https://qiita-image-store.s3.amazonaws.com/0/254604/94aa75a6-b47c-fa1a-62b8-208788c548a5.png)
 
```python
index = np.random.choice(10000, batch_size)
x = images_test_x[index]
labels = np.argmax(labels_test[index], axis = 1)

predicts = bl.prediction(x, n_in, n_units_1, n_units_2, n_out, model_path)

print (np.shape(x))
print (np.shape(predicts))

fig = plt.figure(figsize = (4, 1))

ax1 = fig.add_subplot(2, 3, 1)
ax1.imshow(np.reshape(x[0], [14, 28]), cmap = 'gray')
ax1.set_axis_off()
#ax1.set_title('Input')

ax2 = fig.add_subplot(2, 3, 4)
ax2.imshow(np.reshape(predicts[0], [14, 28]), cmap = 'gray')
ax2.set_axis_off()
#ax2.set_title('Predict')

ax3 = fig.add_subplot(2, 3, 2)
ax3.imshow(np.reshape(x[1], [14, 28]), cmap = 'gray')
ax3.set_axis_off()
#ax3.set_title('Input')

ax4 = fig.add_subplot(2, 3, 5)
ax4.imshow(np.reshape(predicts[1], [14, 28]), cmap = 'gray')
ax4.set_axis_off()
#ax4.set_title('Predict')

ax5 = fig.add_subplot(2, 3, 3)
ax5.imshow(np.reshape(x[2], [14, 28]), cmap = 'gray')
ax5.set_axis_off()
#ax5.set_title('Input')

ax6 = fig.add_subplot(2, 3, 6)
ax6.imshow(np.reshape(predicts[2], [14, 28]), cmap = 'gray')
ax6.set_axis_off()
#ax6.set_title('Predict')

plt.show()
```
![image.png](https://qiita-image-store.s3.amazonaws.com/0/254604/f6458144-8a7b-4369-e25c-52804d76e971.png)