Small compatibility fixes. (odlgroup#1633)

* Compatibility with scikit-image>=0.17.

* Compatibility with numpy>=1.24.

Older versions would automatically convert the meshgrid used for scikit-image Radon transform
to a ragged array, i.e. array of arrays. Newer versions do not do this anymore and need to
be explicitly asked for it.

odl/discr/discr_utils.py

@@ -553,8 +553,9 @@ def __call__(self, x, out=None):
 
         Parameters
         ----------
-        x : `meshgrid` or `numpy.ndarray`
-            Evaluation points of the interpolator
+        x : `meshgrid` (i.e., tuple of arrays) if `input_type` is meshgrid,
+            else `numpy.ndarray`.
+            Evaluation points of the interpolator.
         out : `numpy.ndarray`, optional
             Array to which the results are written. Needs to have
             correct shape according to input ``x``.
@@ -565,7 +566,12 @@ def __call__(self, x, out=None):
             Interpolated values. If ``out`` was given, the returned
             object is a reference to it.
         """
-        x = np.asarray(x)
+        if self.input_type == 'meshgrid':
+            # Given a meshgrid, the evaluation will be on a ragged array.
+            x = np.asarray(x, dtype=object)
+        else:
+            x = np.asarray(x)
+
         ndim = len(self.coord_vecs)
         scalar_out = False
 

odl/tomo/backends/skimage_radon.py

@@ -152,13 +152,19 @@ def skimage_radon_back_projector(sinogram, geometry, vol_space, out=None):
         # Only do asserts here since these are backend functions
         assert out in vol_space
 
+    # scikit-image changed the name of this parameter in version 0.17
+    if (skimage.__version__ < '0.17'):
+        filter_disable = {"filter": None}
+    else:
+        filter_disable = {"filter_name": None}
+
     # Rotate back from (rows, cols) to (x, y), then back-project (no filter)
     backproj = iradon(
         skimage_sinogram.asarray().T,
         theta,
         output_size=vol_space.shape[0],
-        filter=None,
         circle=False,
+        **filter_disable
     )
     out[:] = np.rot90(backproj, -1)