# HG changeset patch
# User Peter Meerwald <pmeerw@cosy.sbg.ac.at>
# Date 1210952371 -7200
# Node ID b5e69130d7e92db515e8efec6725e965908f02b7
# Parent  5bac33d0dad64c3aabf8842c90dd6e4da3288c53
4x4 speedup

diff -r 5bac33d0dad6 -r b5e69130d7e9 pydct/t4x4.py
--- a/pydct/t4x4.py	Wed May 07 00:02:48 2008 +0200
+++ b/pydct/t4x4.py	Fri May 16 17:39:31 2008 +0200
@@ -1,39 +1,41 @@
 import numpy
 
+_fc = numpy.array(
+        [[ 1,  1,  1,  1], 
+         [ 2,  1, -1, -2], 
+         [ 1, -1, -1,  1], 
+         [ 1, -2,  2, -1]], numpy.float)
+_fc = _fct.T
+_fe = numpy.array(
+        [[0.25, 0.15811388, 0.25, 0.15811388], 
+         [0.15811388, 0.1, 0.15811388, 0.1],
+         [0.25, 0.15811388, 0.25, 0.15811388], 
+         [0.15811388, 0.1, 0.15811388, 0.1]], numpy.float)
+
+_ic = numpy.array(
+        [[1, 1, 1, 0.5], 
+         [1, 0.5, -1, -1], 
+         [1, -0.5, -1, 1], 
+         [1, -1, 1, -0.5]], numpy.float)
+_ict = _iec.T         
+_ie = numpy.array(
+        [[0.25, 0.31622777, 0.25, 0.31622777], 
+         [0.31622777, 0.4, 0.31622777, 0.4], 
+         [0.25, 0.31622777, 0.25, 0.31622777],
+         [0.31622777, 0.4, 0.31622777, 0.4]], numpy.float)
+
 def fdct4x4(b):
     '''
     Compute the approximate 4x4 DCT coefficients of an array 
     as defined by H.264/AVC.
     '''
-    c, e = \
-        numpy.array(
-            [[ 1,  1,  1,  1], 
-             [ 2,  1, -1, -2], 
-             [ 1, -1, -1,  1], 
-             [ 1, -2,  2, -1]], numpy.float), \
-        numpy.array(
-            [[0.25, 0.15811388, 0.25, 0.15811388], 
-             [0.15811388, 0.1, 0.15811388, 0.1],
-             [0.25, 0.15811388, 0.25, 0.15811388], 
-             [0.15811388, 0.1, 0.15811388, 0.1]], numpy.float)
         
-    return numpy.dot(c, numpy.dot(b, numpy.transpose(c))) * e
+    return numpy.dot(_fc, numpy.dot(b, _fct)) * _fe
 
 def idct4x4(b):
     '''
     Compute the inverse 4x4 DCT of the array.
     '''
-    c, e = \
-        numpy.array(
-            [[1, 1, 1, 0.5], 
-             [1, 0.5, -1, -1], 
-             [1, -0.5, -1, 1], 
-             [1, -1, 1, -0.5]], numpy.float), \
-        numpy.array(
-            [[0.25, 0.31622777, 0.25, 0.31622777], 
-             [0.31622777, 0.4, 0.31622777, 0.4], 
-             [0.25, 0.31622777, 0.25, 0.31622777],
-             [0.31622777, 0.4, 0.31622777, 0.4]], numpy.float)
 
-    return numpy.dot(c, numpy.dot(b*e, numpy.transpose(c)))
+    return numpy.dot(_ic, numpy.dot(b*_ie, _ict))