Created by: xieshufu

配置了一个网络，在PADDLE v2下运行，在增加了ctc_error度量后，但在日志里不显示error信息：

ctc_eval = paddle.evaluator.ctc_error(input=output, label=lbl)
     trainer = paddle.trainer.SGD(
         cost=cost,
         parameters=parameters,
         update_equation=momentum_optimizer,
         extra_layers=ctc_eval)

训练日志的显示信息如下：

 13 shuffle batch list len: 30208
 14 
 15 Pass 0, Batch 0, Cost 64.853592, {}
 16 .........
 17 Pass 0, Batch 10, Cost 55.328705, {}
 18 .........
 19 Pass 0, Batch 20, Cost 54.045830, {}
 20 .........
 21 Pass 0, Batch 30, Cost 63.349789, {}
 22 .........
 23 Pass 0, Batch 40, Cost 28.554266, {}
 24 .........
 25 Pass 0, Batch 50, Cost 27.816626, {}
 26 .........
 27 Pass 0, Batch 60, Cost 22.405493, {}

烦请PADDLE同学进行支持！ 希望能够显示的信息类似这样的， 方便对模型的精度做判断：

I0901 05:03:12.769793  5485 TrainerInternal.cpp:165]  Batch=312 samples=9984 AvgCost=1.06051 CurrentCost=1.06051 Eval: error=0.0436963  deletions error=0.00442531  insertions error=0.00216684  substitutions error=0.0371042  sequences error=0.151542  CurrentEval: error=0.0436963  deletions error=0.00442531  insertions error=0.00216684  substitutions error=0.0371042  sequences error=0.151542