https://github.com/torch/nn/blob/master/doc/simple.md#nn.MM
th> a = torch.ones(2,3)
th> b = torch.ones(3,4)
th> nn.MM()({a,b})
3 3 3 3 
 3 3 3 3
th> a = torch.ones(1,2,3)
th> b = torch.ones(1,3,4)
th> nn.MM()({a,b})
(1,.,.) = 
 3 3 3 3 
 3 3 3 3
th> a = torch.ones(1,2)
th> b = torch.ones(1,3)
th> nn.MM(true,false)({a,b})
1 1 1 
 1 1 1
th> a = torch.ones(2,2)
th> b = torch.ones(2,3)
th> nn.MM(true,false)({a,b})
2 2 2 
 2 2 2
th> a = torch.ones(5,2)
th> b = torch.ones(5,3)
th> nn.MM(true,false)({a,b})
5 5 5 
 5 5 5
th> a = torch.ones(5,4,1)
th> b = torch.ones(5,4,2)
th> nn.MM(true,false)({a,b})
(1,.,.) = 
 4 4
(2,.,.) = 
 4 4
(3,.,.) = 
 4 4
(4,.,.) = 
 4 4
(5,.,.) = 
 4 4 
 [torch.DoubleTensor of size 5x1x2]
                










