生成对抗网络DCGAN+Tensorflow代码学习笔记（三）----ops.py

ops.py主要定义了一些变量连接的函数、批处理规范化的函数、卷积函数、解卷积函数、激励函数、线性运算函数。

import math
import numpy as np 
import tensorflow as tf
#导入tensorflow.python.framework模块，包含了tensorflow中图、张量等的定义操作
from tensorflow.python.framework import ops

from utils import *

try:
  image_summary = tf.image_summary
  scalar_summary = tf.scalar_summary
  histogram_summary = tf.histogram_summary
  merge_summary = tf.merge_summary
  SummaryWriter = tf.train.SummaryWriter
except:
  image_summary = tf.summary.image
  scalar_summary = tf.summary.scalar
  histogram_summary = tf.summary.histogram
  merge_summary = tf.summary.merge
  SummaryWriter = tf.summary.FileWriter
#连接多个tensor
if "concat_v2" in dir(tf):
  def concat(tensors, axis, *args, **kwargs):
    return tf.concat_v2(tensors, axis, *args, **kwargs)
else:
  def concat(tensors, axis, *args, **kwargs):
    return tf.concat(tensors, axis, *args, **kwargs)
#函数批处理规范化
class batch_norm(object):
  def __init__(self, epsilon=1e-5, momentum = 0.9, name="batch_norm"):
    with tf.variable_scope(name):
      self.epsilon  = epsilon
      self.momentum = momentum
      self.name = name

  def __call__(self, x, train=True):
    return tf.contrib.layers.batch_norm(x,
                      decay=self.momentum, 
                      updates_collections=None,
                      epsilon=self.epsilon,
                      scale=True,
                      is_training=train,
                      scope=self.name)
#定义conv_cond_concat(x,y)函数。连接x,y与Int32型的[x_shapes[0], x_shapes[1], x_shapes[2], y_shapes[3]]维度的张量乘积。
def conv_cond_concat(x, y):
  """Concatenate conditioning vector on feature map axis."""
  x_shapes = x.get_shape()
  y_shapes = y.get_shape()
  return concat([
    x, y*tf.ones([x_shapes[0], x_shapes[1], x_shapes[2], y_shapes[3]])], 3)
#卷积层
def conv2d(input_, output_dim, 
       k_h=5, k_w=5, d_h=2, d_w=2, stddev=0.02,
       name="conv2d"):
  with tf.variable_scope(name):
    w = tf.get_variable('w', [k_h, k_w, input_.get_shape()[-1], output_dim],
              initializer=tf.truncated_normal_initializer(stddev=stddev))
    conv = tf.nn.conv2d(input_, w, strides=[1, d_h, d_w, 1], padding='SAME')

    biases = tf.get_variable('biases', [output_dim], initializer=tf.constant_initializer(0.0))
    conv = tf.reshape(tf.nn.bias_add(conv, biases), conv.get_shape())

    return conv
#反卷积层
def deconv2d(input_, output_shape,
       k_h=5, k_w=5, d_h=2, d_w=2, stddev=0.02,
       name="deconv2d", with_w=False):
  with tf.variable_scope(name):
    # filter : [height, width, output_channels, in_channels]
    w = tf.get_variable('w', [k_h, k_w, output_shape[-1], input_.get_shape()[-1]],
              initializer=tf.random_normal_initializer(stddev=stddev))
    
    try:
      deconv = tf.nn.conv2d_transpose(input_, w, output_shape=output_shape,
                strides=[1, d_h, d_w, 1])

    # Support for verisons of TensorFlow before 0.7.0
    except AttributeError:
      deconv = tf.nn.deconv2d(input_, w, output_shape=output_shape,
                strides=[1, d_h, d_w, 1])

    biases = tf.get_variable('biases', [output_shape[-1]], initializer=tf.constant_initializer(0.0))
    deconv = tf.reshape(tf.nn.bias_add(deconv, biases), deconv.get_shape())

    if with_w:
      return deconv, w, biases
    else:
      return deconv
#定义一个lrelu激励函数
def lrelu(x, leak=0.2, name="lrelu"):
  return tf.maximum(x, leak*x)
#进行线性运算，获取一个随机正态分布矩阵，获取初始偏置值，如果with_w为真，则返回xw+b，权值w和偏置值b；否则返回xw+b。
def linear(input_, output_size, scope=None, stddev=0.02, bias_start=0.0, with_w=False):
  shape = input_.get_shape().as_list()

  with tf.variable_scope(scope or "Linear"):
    matrix = tf.get_variable("Matrix", [shape[1], output_size], tf.float32,
                 tf.random_normal_initializer(stddev=stddev))
    bias = tf.get_variable("bias", [output_size],
      initializer=tf.constant_initializer(bias_start))
    if with_w:
      return tf.matmul(input_, matrix) + bias, matrix, bias
    else:
      return tf.matmul(input_, matrix) + bias