Created by: typhoonzero

When start writing an evaluator operator, I found that I have to store a global status like total_samples and total_score to calculate the error rate of current forward iteration, so that I can increase these values every forward, like total_samples += batch_size and total_score += score.

A simply thought is to add a member function CreateOpVar in InferShapeContext, and name the variable like [operator_id]_var_name to avoid variable name conflict.

Can we discuss about whether we need to add this to current framework?