refactor diagonals
refactor diagonals

ktnyt/chainer,niboshi/chainer,jnishi/chainer,okuta/chainer,niboshi/chainer,jnishi/chainer,hvy/chainer,okuta/chainer,ktnyt/chainer,chainer/chainer,keisuke-umezawa/chainer,niboshi/chainer,okuta/chainer,okuta/chainer,wkentaro/chainer,wkentaro/chainer,keisuke-umezawa/chainer,chainer/chainer,ktnyt/chainer,keisuke-umezawa/chainer,hvy/chainer,ronekko/chainer,rezoo/chainer,keisuke-umezawa/chainer,tkerola/chainer,ktnyt/chainer,hvy/chainer,wkentaro/chainer,jnishi/chainer,pfnet/chainer,hvy/chainer,jnishi/chainer,chainer/chainer,wkentaro/chainer,niboshi/chainer,chainer/chainer