Fixing pyramid scaling factor (#238)

* Fixing pyramid scaling factor

* fix pyramid test

* fix test again

Author: JoOkuma

iohub/ngff/nodes.py

@@ -946,7 +946,7 @@ def initialize_pyramid(self, levels: int) -> None:
             for tr in transforms:
                 if tr.type == "scale":
                     for i in range(len(tr.scale))[-3:]:
-                        tr.scale[i] /= factor
+                        tr.scale[i] *= factor
 
             self.create_zeros(
                 name=str(level),

tests/pyramid/test_pyramid.py

@@ -18,7 +18,6 @@ def _mock_fov(
     shape: tuple[int, ...],
     scale: tuple[float, float, float],
 ) -> Position:
-
     ds_path = tmp_path / "ds.zarr"
     channels = [str(i) for i in range(shape[1])]
 
@@ -51,7 +50,6 @@ def _mock_fov(
 
 @pytest.mark.parametrize("ndim", [2, 5])
 def test_pyramid(tmp_path: Path, ndim: int) -> None:
-
     # not all shapes not divisible by 2
     shape = (2, 2, 67, 115, 128)[-ndim:]
     scale = (2, 0.5, 0.5)[-min(3, ndim) :]
@@ -79,7 +77,7 @@ def test_pyramid(tmp_path: Path, ndim: int) -> None:
             .scale
         )
         assert np.all(level_scale[:-3] == 1)
-        assert np.allclose(scale / level_scale[-3:], 2**level)
+        assert np.allclose(level_scale[-3:] / scale, 2**level)
 
         assert fov.metadata.multiscales[0].datasets[level].path == str(level)