backward_test build passes
backward_test build passes

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