Improve documents of Trainer
Improve documents of Trainer

ktnyt/chainer,okuta/chainer,jnishi/chainer,okuta/chainer,keisuke-umezawa/chainer,keisuke-umezawa/chainer,hvy/chainer,jnishi/chainer,niboshi/chainer,cupy/cupy,anaruse/chainer,wkentaro/chainer,jnishi/chainer,wkentaro/chainer,chainer/chainer,cupy/cupy,keisuke-umezawa/chainer,aonotas/chainer,hvy/chainer,niboshi/chainer,ktnyt/chainer,keisuke-umezawa/chainer,wkentaro/chainer,niboshi/chainer,kiyukuta/chainer,okuta/chainer,rezoo/chainer,hvy/chainer,okuta/chainer,ktnyt/chainer,ysekky/chainer,cupy/cupy,jnishi/chainer,niboshi/chainer,pfnet/chainer,hvy/chainer,wkentaro/chainer,tkerola/chainer,cupy/cupy,chainer/chainer,delta2323/chainer,kashif/chainer,chainer/chainer,ronekko/chainer,kikusu/chainer,kikusu/chainer,ktnyt/chainer,chainer/chainer