Replace 256 with kMaxReductionBlockSize / 2
Replace 256 with kMaxReductionBlockSize / 2

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