# HG changeset patch
# User Anders Claesson <anders@ru.is>
# Date 1248543177 0
# Node ID 7ee14d081bde6b08274996ed9251c8746fde4462
# Parent  78ea5b9e2f85b9befff57c38d28fb2266f8250e9
Improve running time of inverse method

diff -r 78ea5b9e2f85 -r 7ee14d081bde sage/combinat/permutation.py
--- a/sage/combinat/permutation.py	Sat Jul 25 06:29:52 2009 +0000
+++ b/sage/combinat/permutation.py	Sat Jul 25 17:32:57 2009 +0000
@@ -890,7 +890,10 @@
             sage: Permutation([2, 4, 1, 5, 3]).inverse()
             [3, 1, 5, 2, 4]
         """
-        return Permutation([self.index(i+1)+1 for i in range(len(self))])
+        w = range(len(self))
+        for i,j in enumerate(self):
+            w[j-1] = i+1
+        return Permutation(w)
 
     def _icondition(self, i):
         """