avoid np.round

util/resample.py

@@ -62,6 +62,7 @@ def resample_with_wcs(targetwcs, wcs, Limages=[], L=3, spline=True,
     table: use Lanczos3 look-up table?
 
     intType: type to return for integer pixel coordinates.
+    (however, Yi,Xi may still be returned as int32)
     '''
     ### DEBUG
     #ps = PlotSequence('resample')
@@ -220,8 +221,9 @@ def expand_axes():
         # the lanczos3_interpolate function below requires int32!
         itype = np.int32
 
-    ixi = np.round(fxi).astype(itype)
-    iyi = np.round(fyi).astype(itype)
+    # (f + 0.5).astype(int) is often faster than round().astype(int) or rint!
+    ixi = (fxi + 0.5).astype(itype)
+    iyi = (fyi + 0.5).astype(itype)
 
     # Cut to in-bounds pixels.
     I,J = np.nonzero((ixi >= 0) * (ixi < w) * (iyi >= 0) * (iyi < h))