tf.app.run() 是如何工作的? [英] How does tf.app.run() work?

问题描述

tf.app.run() 在 Tensorflow 翻译演示中是如何工作的?

How does tf.app.run() work in Tensorflow translate demo?

在tensorflow/models/rnn/translate/translate.py 中，有一个对tf.app.run() 的调用.是怎么处理的?

In tensorflow/models/rnn/translate/translate.py, there is a call to tf.app.run(). How is it being handled?

if __name__ == "__main__":
    tf.app.run() 

推荐答案

if __name__ == "__main__":

表示当前文件在shell下执行，而不是作为模块导入.

means current file is executed under a shell instead of imported as a module.

tf.app.run()

正如你通过文件app.py

def run(main=None, argv=None):
  """Runs the program with an optional 'main' function and 'argv' list."""
  f = flags.FLAGS

  # Extract the args from the optional `argv` list.
  args = argv[1:] if argv else None

  # Parse the known flags from that list, or from the command
  # line otherwise.
  # pylint: disable=protected-access
  flags_passthrough = f._parse_flags(args=args)
  # pylint: enable=protected-access

  main = main or sys.modules['__main__'].main

  # Call the main function, passing through any arguments
  # to the final program.
  sys.exit(main(sys.argv[:1] + flags_passthrough))

让我们逐行分解:

flags_passthrough = f._parse_flags(args=args)

这确保您通过命令行传递的参数是有效的，例如python my_model.py --data_dir='...' --max_iteration=10000 其实这个特性是基于python标准的argparse模块实现的.

This ensures that the argument you pass through command line is valid,e.g. python my_model.py --data_dir='...' --max_iteration=10000 Actually, this feature is implemented based on python standard argparse module.

main = main or sys.modules['__main__'].main

=右侧的第一个main是当前函数的第一个参数run(main=None, argv=None).而 sys.modules['__main__'] 表示当前正在运行的文件(例如 my_model.py).

The first main in right side of = is the first argument of current function run(main=None, argv=None) . While sys.modules['__main__'] means current running file(e.g. my_model.py).

所以有两种情况:

1. 你在 my_model.py 中没有 main 函数那么你必须调用 tf.app.run(my_main_running_function)

1. You don't have a main function in my_model.py Then you have to call tf.app.run(my_main_running_function)

您在 my_model.py 中有一个 main 函数.(主要是这种情况.)

you have a main function in my_model.py. (This is mostly the case.)

最后一行:

sys.exit(main(sys.argv[:1] + flags_passthrough))

确保您的 main(argv) 或 my_main_running_function(argv) 函数被正确解析参数调用.

ensures your main(argv) or my_main_running_function(argv) function is called with parsed arguments properly.

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