Merge pull request #73 from giovp/feature/dims-warning

raise error for invalid scale factors

Author: thewtex

.gitignore

@@ -10,4 +10,4 @@ examples/sub-I46_ses-SPIM_sample-BrocaAreaS01_stain-GAD67_chunk-00_SPIM*
 examples/dask-worker-space/
 
 # Byte-compiled / optimized / DLL files
-__pycache__/
+__pycache__/

multiscale_spatial_image/to_multiscale/to_multiscale.py

@@ -83,6 +83,18 @@ def to_multiscale(
     out_chunks = chunks
     if out_chunks is None:
         out_chunks = default_chunks
+    
+    # check for valid scale factors
+    current_shape = {d:s for (d, s) in zip(image.dims, image.shape) if d not in {"t", "c"}}
+
+    for scale_factor in scale_factors:
+        if isinstance(scale_factor, dict):
+            current_shape = {k: (current_shape[k] / s) for (k, s) in scale_factor.items()}
+        elif isinstance(scale_factor, int):
+            current_shape = {k: (s / scale_factor) for (k, s) in current_shape.items()}
+        for k,v in current_shape.items():
+            if v < 1:
+                raise ValueError(f"Scale factor {scale_factor} is incompatible with image shape {image.shape} along dimension `{k}`.")
 
     current_input = image.chunk(out_chunks)
     # https://github.com/pydata/xarray/issues/5219

test/test_to_multiscale.py

@@ -1,15 +1,20 @@
 import xarray as xr
-
-from multiscale_spatial_image import Methods, to_multiscale 
+import pytest
+from multiscale_spatial_image import to_multiscale
 
 from ._data import input_images
 
+
 def test_base_scale(input_images):
     image = input_images["cthead1"]
 
     multiscale = to_multiscale(image, [])
-    xr.testing.assert_equal(image, multiscale['scale0'].ds["cthead1"])
+    xr.testing.assert_equal(image, multiscale["scale0"].ds["cthead1"])
 
     image = input_images["small_head"]
     multiscale = to_multiscale(image, [])
-    xr.testing.assert_equal(image, multiscale['scale0'].ds["small_head"])
+    xr.testing.assert_equal(image, multiscale["scale0"].ds["small_head"])
+
+    with pytest.raises(ValueError):
+        to_multiscale(image, scale_factors=[500])
+        to_multiscale(image, scale_factors=[{"x": 10}, {"x": 500, "y": 10}])