FIX: Avoid/suppress expected warnings

Author: effigies

nibabel/casting.py

@@ -4,6 +4,7 @@
 casting.  Others work round numpy casting to and from python ints
 """
 
+import warnings
 from numbers import Integral
 from platform import processor, machine
 
@@ -349,8 +350,9 @@ def _check_maxexp(np_type, maxexp):
     dt = np.dtype(np_type)
     np_type = dt.type
     two = np_type(2).reshape((1,))  # to avoid upcasting
-    return (np.isfinite(two ** (maxexp - 1)) and
-            not np.isfinite(two ** maxexp))
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore", RuntimeWarning)  # Expected overflow warning
+        return np.isfinite(two ** (maxexp - 1)) and not np.isfinite(two ** maxexp)
 
 
 def as_int(x, check=True):

nibabel/processing.py

@@ -300,8 +300,10 @@ def smooth_image(img,
         fwhm = np.zeros((n_dim,))
         fwhm[:3] = fwhm_scalar
     # Voxel sizes
-    RZS = img.affine[:-1, :n_dim]
+    RZS = img.affine[:, :n_dim]
     vox = np.sqrt(np.sum(RZS ** 2, 0))
+    # Avoid divisions by zero for 4+D images
+    vox[3:] = 1
     # Smoothing in terms of voxels
     vox_fwhm = fwhm / vox
     vox_sd = fwhm2sigma(vox_fwhm)