SF.net SVN: matplotlib:[8965] trunk/matplotlib/lib/matplotlib/colors.py

[<ef...@us...>]

Revision: 8965
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=8965&view=rev
Author:   efiring
Date:     2011-02-09 04:16:08 +0000 (Wed, 09 Feb 2011)

Log Message:
-----------
Normalize: major speed-up via bypassing masked array division

Modified Paths:
--------------
    trunk/matplotlib/lib/matplotlib/colors.py

Modified: trunk/matplotlib/lib/matplotlib/colors.py
===================================================================
--- trunk/matplotlib/lib/matplotlib/colors.py	2011-02-08 13:27:16 UTC (rev 8964)
+++ trunk/matplotlib/lib/matplotlib/colors.py	2011-02-09 04:16:08 UTC (rev 8965)
@@ -853,8 +853,11 @@
                 mask = ma.getmask(result)
                 result = ma.array(np.clip(result.filled(vmax), vmin, vmax),
                                   mask=mask)
-            result -= vmin
-            result /= vmax - vmin
+            # ma division is very slow; we can take a shortcut
+            resdat = result.data
+            resdat -= vmin
+            resdat /= (vmax - vmin)
+            result = np.ma.array(resdat, mask=result.mask, copy=False)
         if is_scalar:
             result = result[0]
         return result


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