tensor_a is of shape (256, 4, 64) and tensor_b is of shape (256, 64, 1)
    res = None
    for u in range(256):
        temp = torch.matmul(tensor_a[u, :, :], tensor_b)
        temp = temp.sum().unsqueeze(-1)
        if u == 0:
            res = temp
        else:
            res = torch.cat((res, temp), -1)

    res = res.unsqueeze(-1)

Can anyone get the result using torch functions rather than use looping?