Sliding Window on 2D Tensor using PyTorch

Question

How can we use a sliding window on a 2D PyTorch tensor t with shape (6, 10) such that we end up with a 3D PyTorch tensor with shape (3, 4, 10) ?

For example, if we have the tensor t :

t = torch.range(1, 6*10).reshape((7, 10))

tensor([[ 1.,  2.,  3.,  4.,  5.,  6.,  7.,  8.,  9., 10.],
        [11., 12., 13., 14., 15., 16., 17., 18., 19., 20.],
        [21., 22., 23., 24., 25., 26., 27., 28., 29., 30.],
        [31., 32., 33., 34., 35., 36., 37., 38., 39., 40.],
        [41., 42., 43., 44., 45., 46., 47., 48., 49., 50.],
        [51., 52., 53., 54., 55., 56., 57., 58., 59., 60.]]

how can we reshape it (using PyTorch) such that we get the tensor:

tensor([[ 1.,  2.,  3.,  4.,  5.,  6.,  7.,  8.,  9., 10.],
        [11., 12., 13., 14., 15., 16., 17., 18., 19., 20.],
        [21., 22., 23., 24., 25., 26., 27., 28., 29., 30.],
        [31., 32., 33., 34., 35., 36., 37., 38., 39., 40.]],

        [[11., 12., 13., 14., 15., 16., 17., 18., 19., 20.],
        [21., 22., 23., 24., 25., 26., 27., 28., 29., 30.],
        [31., 32., 33., 34., 35., 36., 37., 38., 39., 40.],
        [41., 42., 43., 44., 45., 46., 47., 48., 49., 50.]],

        [[21., 22., 23., 24., 25., 26., 27., 28., 29., 30.],
        [31., 32., 33., 34., 35., 36., 37., 38., 39., 40.],
        [41., 42., 43., 44., 45., 46., 47., 48., 49., 50.],
        [51., 52., 53., 54., 55., 56., 57., 58., 59., 60.]])

Answer 1

Looks like a case for unfold :

t.unfold(0,4,1).transpose(2,1)

Output:

tensor([[[ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9],
         [10, 11, 12, 13, 14, 15, 16, 17, 18, 19],
         [20, 21, 22, 23, 24, 25, 26, 27, 28, 29],
         [30, 31, 32, 33, 34, 35, 36, 37, 38, 39]],

        [[10, 11, 12, 13, 14, 15, 16, 17, 18, 19],
         [20, 21, 22, 23, 24, 25, 26, 27, 28, 29],
         [30, 31, 32, 33, 34, 35, 36, 37, 38, 39],
         [40, 41, 42, 43, 44, 45, 46, 47, 48, 49]],

        [[20, 21, 22, 23, 24, 25, 26, 27, 28, 29],
         [30, 31, 32, 33, 34, 35, 36, 37, 38, 39],
         [40, 41, 42, 43, 44, 45, 46, 47, 48, 49],
         [50, 51, 52, 53, 54, 55, 56, 57, 58, 59]]])