Add change in math.cc
Add change in math.cc

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