From 97db2a5bd7e5c5339319e366cc34980c99b537e6 Mon Sep 17 00:00:00 2001
From: Neil Lawrence <neil@stefano.(none)>
Date: Tue, 2 Apr 2013 16:53:42 +0200
Subject: [PATCH] Edit to linalg.py PCA function to stop it changing data
 matrix.

---
 GPy/util/linalg.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/GPy/util/linalg.py b/GPy/util/linalg.py
index 45644b41..59f598f9 100644
--- a/GPy/util/linalg.py
+++ b/GPy/util/linalg.py
@@ -146,9 +146,9 @@ def PCA(Y, Q):
     if not np.allclose(Y.mean(axis=0), 0.0):
         print "Y is not zero mean, centering it locally (GPy.util.linalg.PCA)"
         
-        Y -= Y.mean(axis=0) 
+        #Y -= Y.mean(axis=0) 
 
-    Z = linalg.svd(Y, full_matrices = False)
+    Z = linalg.svd(Y-Y.mean(axis=0), full_matrices = False)
     [X, W] = [Z[0][:,0:Q], np.dot(np.diag(Z[1]), Z[2]).T[:,0:Q]]
     v = X.std(axis=0)
     X /= v;