The graph couldn't be sorted in topological order

[cccxinli]

When training SRGAN_MSE,I got the error before training steps.How should I correct this mistake? ` Instructions for updating: Use standard file APIs to check for files with this prefix. Optimization starts!!! 2019-04-25 22:19:05.498392: E tensorflow/core/grappler/optimizers/dependency_optimizer.cc:704] Iteration = 0, topological sort failed with message: The graph couldn't be sorted in topological order. 2019-04-25 22:19:05.573480: E tensorflow/core/grappler/optimizers/dependency_optimizer.cc:704] Iteration = 1, topological sort failed with message: The graph couldn't be sorted in topological order. 2019-04-25 22:19:06.019904: E tensorflow/core/grappler/optimizers/dependency_optimizer.cc:704] Iteration = 0, topological sort failed with message: The graph couldn't be sorted in topological order. 2019-04-25 22:19:06.074874: E tensorflow/core/grappler/optimizers/dependency_optimizer.cc:704] Iteration = 1, topological sort failed with message: The graph couldn't be sorted in topological order. 2019-04-25 22:20:13.189917: E tensorflow/core/grappler/optimizers/dependency_optimizer.cc:704] Iteration = 0, topological sort failed with message: The graph couldn't be sorted in topological order. 2019-04-25 22:20:13.261664: E tensorflow/core/grappler/optimizers/dependency_optimizer.cc:704] Iteration = 1, topological sort failed with message: The graph couldn't be sorted in topological order. 2019-04-25 22:20:13.684844: E tensorflow/core/grappler/optimizers/dependency_optimizer.cc:704] Iteration = 0, topological sort failed with message: The graph couldn't be sorted in topological order. 2019-04-25 22:20:13.736548: E tensorflow/core/grappler/optimizers/dependency_optimizer.cc:704] Iteration = 1, topological sort failed with message: The graph couldn't be sorted in topological order.

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