implement pad
implement pad

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