ptb_fp16

$ CHAINER_DTYPE=float16 python train_ptb.py -d 0 -e 10
#vocab = 10000
epoch       iteration   perplexity  val_perplexity
0           500         326440
0           1000        301342
1           1500        298940      inf
1           2000        334369
1           2500        334369
2           3000        306202      inf
2           3500        339762
3           4000        321258      inf
3           4500        334369
3           5000        316159
4           5500        353628      inf
4           6000        313640
4           6500        318698
5           7000        339762      inf
5           7500        316159
6           8000        294196      inf
6           8500        326440
6           9000        371016
7           9500        316159      inf
7           10000       348015
7           10500       318698
8           11000       306202      inf
8           11500       326440
9           12000       318698      inf
9           12500       323838
9           13000       291851
test
test perplexity: inf

ptb_fp32

$ python train_ptb.py -d 0 -e 10
#vocab = 10000
epoch       iteration   perplexity  val_perplexity............]  3.69%
0           500         696.825
0           1000        300.379
1           1500        227.869     207.567
1           2000        202.66
1           2500        169.194
2           3000        156.06      152.122
2           3500        149.424
3           4000        137.197     129.369
3           4500        130.502
3           5000        119.299
4           5500        117.775     118.105
4           6000        112.313
4           6500        104.091
5           7000        107.539     109.152
5           7500        100.775
6           8000        92.93       102.855
6           8500        95.7028
6           9000        99.9391
7           9500        83.7397     99.7991
7           10000       93.0974
7           10500       83.7269
8           11000       86.057      96.3761
8           11500       82.3142
9           12000       83.6467     94.6426
9           12500       79.6013
9           13000       77.0567
test
test perplexity: 90.019997959895

runtime_info

$ python
Python 3.7.3 (default, Mar 27 2019, 22:11:17)
[GCC 7.3.0] :: Anaconda, Inc. on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import chainer
>>> chainer.print_runtime_info()
Platform: Linux-4.15.0-50-generic-x86_64-with-debian-buster-sid
Chainer: 7.0.0a1
NumPy: 1.16.4
CuPy:
  CuPy Version          : 7.0.0a1
  CUDA Root             : /usr/local/cuda
  CUDA Build Version    : 10000
  CUDA Driver Version   : 10000
  CUDA Runtime Version  : 10000
  cuDNN Build Version   : 7500
  cuDNN Version         : 7500
  NCCL Build Version    : 2402
  NCCL Runtime Version  : 2402
iDeep: 2.0.0.post3
>>>