在使用tensorflow中,我们常常需要获取某个变量的值,比如:打印某一层的权重,通常我们可以直接利用变量的name属性来获取,但是当我们利用一些第三方的库来构造神经网络的layer时,存在一种情况:就是我们自己无法定义该层的变量,因为是自动进行定义的。
比如用tensorflow的slim库时:
def resnet_stack(images, output_shape, hparams, scope=None): """Create a resnet style transfer block. Args: images: [batch-size, height, width, channels] image tensor to feed as input output_shape: output image shape in form [height, width, channels] hparams: hparams objects scope: Variable scope Returns: Images after processing with resnet blocks. """ end_points = {} if hparams.noise_channel: # separate the noise for visualization end_points['noise'] = images[:, :, :, -1] assert images.shape.as_list()[1:3] == output_shape[0:2] with tf.variable_scope(scope, 'resnet_style_transfer', [images]): with slim.arg_scope( [slim.conv2d], normalizer_fn=slim.batch_norm, kernel_size=[hparams.generator_kernel_size] * 2, stride=1): net = slim.conv2d( images, hparams.resnet_filters, normalizer_fn=None, activation_fn=tf.nn.relu) for block in range(hparams.resnet_blocks): net = resnet_block(net, hparams) end_points['resnet_block_{}'.format(block)] = net net = slim.conv2d( net, output_shape[-1], kernel_size=[1, 1], normalizer_fn=None, activation_fn=tf.nn.tanh, scope='conv_out') end_points['transferred_images'] = net return net, end_points
我们希望获取第一个卷积层的权重weight,该怎么办呢??
在训练时,这些可训练的变量会被tensorflow保存在 tf.trainable_variables() 中,于是我们就可以通过打印 tf.trainable_variables() 来获取该卷积层的名称(或者你也可以自己根据scope来看出来该变量的name ),然后利用tf.get_default_grap().get_tensor_by_name 来获取该变量。
举个简单的例子:
import tensorflow as tf with tf.variable_scope("generate"): with tf.variable_scope("resnet_stack"): #简单起见,这里没有用第三方库来说明, bias = tf.Variable(0.0,name="bias") weight = tf.Variable(0.0,name="weight") for tv in tf.trainable_variables(): print (tv.name) b = tf.get_default_graph().get_tensor_by_name("generate/resnet_stack/bias:0") w = tf.get_default_graph().get_tensor_by_name("generate/resnet_stack/weight:0") with tf.Session() as sess: tf.global_variables_initializer().run() print(sess.run(b)) print(sess.run(w))
结果如下:
以上这篇tensorflow 获取变量&打印权值的实例讲解就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持。