change eps value to being compatible with float16
change eps value to being compatible with float16

chainer/chainer,okuta/chainer,hvy/chainer,niboshi/chainer,niboshi/chainer,chainer/chainer,keisuke-umezawa/chainer,tkerola/chainer,hvy/chainer,chainer/chainer,wkentaro/chainer,pfnet/chainer,wkentaro/chainer,chainer/chainer,keisuke-umezawa/chainer,hvy/chainer,niboshi/chainer,keisuke-umezawa/chainer,wkentaro/chainer,niboshi/chainer,keisuke-umezawa/chainer,okuta/chainer,wkentaro/chainer,hvy/chainer,okuta/chainer,okuta/chainer