Reverted change in the computation when masks elements are relative s…

…maller than patch sizes

zarrdataset/_samplers.py

@@ -153,7 +153,7 @@ def _compute_grid(self, chunk_mask: np.ndarray,
 
         else:
             active_coordinates = np.meshgrid(
-                *[np.arange(round(image_size[ax] / ps))
+                *[np.arange(image_size[ax] // ps)
                   for ax, ps in zip(mask_axes, patch_shape)
                   if ax in self.spatial_axes]
             )