Remove deep copy for in-place operation
Remove deep copy for in-place operation

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