TensorFlow中权重的随机初始化的方法

技术  /  管理员 发布于 7年前   162

一开始没看懂stddev是什么参数，找了一下，在tensorflow/python/ops里有random_ops，其中是这么写的：

def random_normal(shape, mean=0.0, stddev=1.0, dtype=types.float32,         seed=None, name=None): """Outputs random values from a normal distribution. Args:  shape: A 1-D integer Tensor or Python array. The shape of the output tensor.  mean: A 0-D Tensor or Python value of type `dtype`. The mean of the normal   distribution.  stddev: A 0-D Tensor or Python value of type `dtype`. The standard deviation   of the normal distribution.  dtype: The type of the output.  seed: A Python integer. Used to create a random seed for the distribution.   See   [`set_random_seed`](../../api_docs/python/constant_op.md#set_random_seed)   for behavior.  name: A name for the operation (optional). Returns:  A tensor of the specified shape filled with random normal values. """

也就是按照正态分布初始化权重，mean是正态分布的平均值，stddev是正态分布的标准差（standard deviation），seed是作为分布的random seed（随机种子，我百度了一下，跟什么伪随机数发生器还有关，就是产生随机数的），在mnist/concolutional中seed赋值为66478，挺有意思，不知道是什么原理。

后面还有truncated_normal的定义：

def truncated_normal(shape, mean=0.0, stddev=1.0, dtype=types.float32,           seed=None, name=None): """Outputs random values from a truncated normal distribution. The generated values follow a normal distribution with specified mean and standard deviation, except that values whose magnitude is more than 2 standard deviations from the mean are dropped and re-picked. Args:  shape: A 1-D integer Tensor or Python array. The shape of the output tensor.  mean: A 0-D Tensor or Python value of type `dtype`. The mean of the   truncated normal distribution.  stddev: A 0-D Tensor or Python value of type `dtype`. The standard deviation   of the truncated normal distribution.  dtype: The type of the output.  seed: A Python integer. Used to create a random seed for the distribution.   See   [`set_random_seed`](../../api_docs/python/constant_op.md#set_random_seed)   for behavior.  name: A name for the operation (optional). Returns:  A tensor of the specified shape filled with random truncated normal values. """

截断正态分布，以前都没听说过。

TensorFlow还提供了平均分布等。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。