eval() and run() in tensorflow

Question

I\'m referring to Deep MNIST for Experts tutorial given by the tensorflow. I have a problem in Train and Evaluate part of that tutorial. There they have giv

Answer 1

If you have only one default session, they are basically the same.

From https://github.com/tensorflow/tensorflow/blob/v1.12.0/tensorflow/python/framework/ops.py#L2351:

op.run() is a shortcut for calling tf.get_default_session().run(op)

From https://github.com/tensorflow/tensorflow/blob/v1.12.0/tensorflow/python/framework/ops.py#L691:

t.eval() is a shortcut for calling tf.get_default_session().run(t)

Difference between Tensor and Operation:

Tensor: https://www.tensorflow.org/api_docs/python/tf/Tensor

Operation: https://www.tensorflow.org/api_docs/python/tf/Operation

Note: the Tensor class will be replaced by Output in the future. Currently these two are aliases for each other.

Answer 2

The difference is in Operations vs. Tensors. Operations use run() and Tensors use eval().

There seems to be a reference to this question in TensorFlow FAQ: https://www.tensorflow.org/programmers_guide/faq#running_a_tensorflow_computation

The section addresses the following question: What is the difference between Session.run() and Tensor.eval()?