removed test file

backprop.py

-import torch
-from torch.autograd import Variable
-
-size = torch.Size([2, 2])
-
-index = torch.tensor([[0, 1], [1, 0]], dtype=torch.long).cuda()
-value = torch.tensor([1, 1], dtype=torch.float).cuda()
-A = torch.cuda.sparse.FloatTensor(index, value, size)
-
-index = torch.tensor([[0, 1], [0, 1]], dtype=torch.long)
-value = torch.tensor([1, 1], dtype=torch.float)
-B = torch.sparse.FloatTensor(index, value, size)