SF.net SVN: matplotlib:[8969] trunk/matplotlib/lib/matplotlib/colors.py

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

Revision: 8969
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=8969&view=rev
Author:   efiring
Date:     2011-02-10 07:37:05 +0000 (Thu, 10 Feb 2011)

Log Message:
-----------
LogNorm: speed-up by dealing with mask explicitly

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

Modified: trunk/matplotlib/lib/matplotlib/colors.py
===================================================================
--- trunk/matplotlib/lib/matplotlib/colors.py	2011-02-10 01:21:27 UTC (rev 8968)
+++ trunk/matplotlib/lib/matplotlib/colors.py	2011-02-10 07:37:05 UTC (rev 8969)
@@ -921,9 +921,17 @@
                                 mask=mask)
             #result = (ma.log(result)-np.log(vmin))/(np.log(vmax)-np.log(vmin))
             # in-place equivalent of above can be much faster
-            np.ma.log(result, result)
-            result -= np.log(vmin)
-            result /= (np.log(vmax) - np.log(vmin))
+            resdat = result.data
+            mask = result.mask
+            if mask is np.ma.nomask:
+                mask = (resdat <= 0)
+            else:
+                mask |= resdat <= 0
+            np.putmask(resdat, mask, 1)
+            np.log(resdat, resdat)
+            resdat -= np.log(vmin)
+            resdat /= (np.log(vmax) - np.log(vmin))
+            result = np.ma.array(resdat, mask=mask, copy=False)
         if is_scalar:
             result = result[0]
         return result


This was sent by the SourceForge.net collaborative development platform, the world's largest Open Source development site.