TensorFlow可以运行多个CPU(没有GPU)吗？

Question

我正在尝试学习分布式TensorFlow.试过这里解释的片段代码:

with tf.device("/cpu:0"):
    W = tf.Variable(tf.zeros([784, 10]))
    b = tf.Variable(tf.zeros([10]))

with tf.device("/cpu:1"):
    y = tf.nn.softmax(tf.matmul(x, W) + b)
    loss = tf.reduce_mean(-tf.reduce_sum(y_ * tf.log(y), reduction_indices=[1]))

收到以下错误:

tensorflow.python.framework.errors_impl.InvalidArgumentError: Cannot assign a device for operation 'MatMul': Operation was explicitly assigned to /device:CPU:1 but available devices are [ /job:localhost/replica:0/task:0/cpu:0 ]. Make sure the device specification refers to a valid device.
     [[Node: MatMul = MatMul[T=DT_FLOAT, transpose_a=false, transpose_b=false, _device="/device:CPU:1"](Placeholder, Variable/read)]]

意味着TensorFlow无法识别CPU:1.

我正在使用40个CPU(cat /proc/cpuinfo | grep processor | wc -l)的RedHat服务器上运行.

有任何想法吗？

Answer 1

点击评论中的链接：

结果应该将会话配置为设备计数 > 1：

config = tf.ConfigProto(device_count={"CPU": 8})
with tf.Session(config=config) as sess:
   ...

有点令人震惊的是，我错过了一些如此基本的东西，而且没有人能够指出一个看起来太明显的错误。

不确定这是我的问题还是 TensorFlow 代码示例和文档的问题。既然是谷歌，我就不得不说是我。