RuntimeError: The Session graph is empty. Add operations to the graph before calling run().解决方法

问题产生的原因：无法执行sess.run()的原因是tensorflow版本不同导致的，tensorflow版本2.0无法兼容版本1.0.

解决办法：tf.compat.v1.disable_eager_execution()

1 import tensorflow as tf
2 tf.compat.v1.disable_eager_execution()
3 hello = tf.constant('Hello, TensorFlow!')
4 config = tf.compat.v1.ConfigProto(allow_soft_placement=True)
5 config.gpu_options.per_process_gpu_memory_fraction = 0.9
6 sess= tf.compat.v1.Session(config=config)
7 print(sess.run(hello))