In master, we reorganized the sparse code to remove all of these extra sparse operations, so you can just use a plain old matrix multiply to go sparse x dense -> dense
i = torch.LongTensor([[0, 1, 1], 
                  [2, 0, 2]])
v = torch.FloatTensor([3, 4, 5]) 
s = torch.sparse.FloatTensor(i, v, torch.Size([2,3]))
d = s.to_dense()
s.matmul(d.t())