title: Tensorflow transfer learning how to load part of layers from one checkpoint file and save all graph vars in another checkpoint file
body: <p>When using tensorflow in machine learning, sometimes we want to pre-train a model,and save the model in a pre-train_model floder by checkpoint file (using saver.save()). And then we want use part of pre-train model layer to init a new network , and save the new train model in a new-train_model folder by using checkpoint files. </p>
  
  <p>So, what can I do to implement this function. </p>