paddle v2 CTC error在训练日志中不显示 #3802
Description
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