Add assertion about strides.dtype in __new__

Author: ValerianRey

src/torchjd/sparse/_structured_sparse_tensor.py

@@ -18,6 +18,8 @@ def __new__(cls, physical: Tensor, strides: Tensor):
         # that the tensor we're wrapping is exactly a Tensor
         assert type(physical) is Tensor
 
+        assert strides.dtype == torch.int64
+
         # Note [Passing requires_grad=true tensors to subclasses]
         # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
         # Calling _make_subclass directly in an autograd context is