from_dense with optional no values

torch_sparse/tensor.py

@@ -30,15 +30,21 @@ class SparseTensor(object):
         return self
 
     @classmethod
-    def from_dense(self, mat: torch.Tensor):
+    def from_dense(self, mat: torch.Tensor, has_value: bool = True):
         if mat.dim() > 2:
             index = mat.abs().sum([i for i in range(2, mat.dim())]).nonzero()
         else:
             index = mat.nonzero()
         index = index.t()
 
-        row, col = index[0], index[1]
-        return SparseTensor(row=row, rowptr=None, col=col, value=mat[row, col],
+        row = index[0]
+        col = index[1]
+
+        value: Optional[torch.Tensor] = None
+        if has_value:
+            value = mat[row, col]
+
+        return SparseTensor(row=row, rowptr=None, col=col, value=value,
                             sparse_sizes=mat.size()[:2], is_sorted=True)
 
     @classmethod