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对tensorflow中tf.nn.conv1d和layers.conv1d的区别详解

2020-02-15 21:16:11
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在用tensorflow做一维的卷积神经网络的时候会遇到tf.nn.conv1d和layers.conv1d这两个函数,但是这两个函数有什么区别呢,通过计算得到一些规律。

1.关于tf.nn.conv1d的解释,以下是Tensor Flow中关于tf.nn.conv1d的API注解:

Computes a 1-D convolution given 3-D input and filter tensors.

Given an input tensor of shape [batch, in_width, in_channels] if data_format is "NHWC", or [batch, in_channels, in_width] if data_format is "NCHW", and a filter / kernel tensor of shape [filter_width, in_channels, out_channels], this op reshapes the arguments to pass them to conv2d to perform the equivalent convolution operation.

Internally, this op reshapes the input tensors and invokes `tf.nn.conv2d`. For example, if `data_format` does not start with "NC", a tensor of shape [batch, in_width, in_channels] is reshaped to [batch, 1, in_width, in_channels], and the filter is reshaped to [1, filter_width, in_channels, out_channels]. The result is then reshaped back to [batch, out_width, out_channels] whereoutwidthisafunctionofthestrideandpaddingasinconv2dwhereoutwidthisafunctionofthestrideandpaddingasinconv2d and returned to the caller.

Args: value: A 3D `Tensor`. Must be of type `float32` or `float64`. filters: A 3D `Tensor`. Must have the same type as `input`. stride: An `integer`. The number of entries by which the filter is moved right at each step. padding: 'SAME' or 'VALID' use_cudnn_on_gpu: An optional `bool`. Defaults to `True`. data_format: An optional `string` from `"NHWC", "NCHW"`. Defaults to `"NHWC"`, the data is stored in the order of [batch, in_width, in_channels]. The `"NCHW"` format stores data as [batch, in_channels, in_width]. name: A name for the operation (optional).

Returns:

A `Tensor`. Has the same type as input.

Raises:

ValueError: if `data_format` is invalid.

什么意思呢?就是说conv1d的参数含义:(以NHWC格式为例,即,通道维在最后)

1、value:在注释中,value的格式为:[batch, in_width, in_channels],batch为样本维,表示多少个样本,in_width为宽度维,表示样本的宽度,in_channels维通道维,表示样本有多少个通道。 事实上,也可以把格式看作如下:[batch, 行数, 列数],把每一个样本看作一个平铺开的二维数组。这样的话可以方便理解。

2、filters:在注释中,filters的格式为:[filter_width, in_channels, out_channels]。按照value的第二种看法,filter_width可以看作每次与value进行卷积的行数,in_channels表示value一共有多少列(与value中的in_channels相对应)。out_channels表示输出通道,可以理解为一共有多少个卷积核,即卷积核的数目。

3、stride:一个整数,表示步长,每次(向下)移动的距离(TensorFlow中解释是向右移动的距离,这里可以看作向下移动的距离)。

4、padding:同conv2d,value是否需要在下方填补0。

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