From e8a193bbfbe4eab7d31c5dacd8481a06907db669 Mon Sep 17 00:00:00 2001
From: George Perendia <artilogica@btconnect.com>
Date: Wed, 20 Oct 2010 11:44:45 +0100
Subject: [PATCH] Track #21: Add partial information: Correcting bug stemming
 from the differences in QZ calculation under Octave and Matlab: modified
 PI_gensys to use C.Sims' Lapack zgges based qzcomplex() qz decomposition
 routine under Octave which gives nearly identical complex results to Matlab
 QZ (except for transpose of q matrix and few sign changes in the output
 matrices)

---
 matlab/partial_information/PI_gensys.m | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/matlab/partial_information/PI_gensys.m b/matlab/partial_information/PI_gensys.m
index ef181b385..3094bb7cf 100644
--- a/matlab/partial_information/PI_gensys.m
+++ b/matlab/partial_information/PI_gensys.m
@@ -153,7 +153,16 @@ end
 
 G0pi=eye(n+FL_RANK+NX);
 try
-    [a b q z v]=qz(G0pi,G1pi);
+  % In Matlab: [aa bb q z v w] = qz(a,b) s.t. qaz = aa, qbz = bb % 
+  % In Octave: [aa bb q z v w] = qz(a,b) s.t. q'az = aa, q'bz=bb %
+  % and qzcomplex() extension based on lapack zgges produces same 
+  % qz output for Octave as Matlab qz() does for Matlab thus:
+  if exist('OCTAVE_VERSION')
+    [a b q z]=qzcomplex(G0pi,G1pi);
+    q=q';
+  else
+    [a b q z]=qz(G0pi,G1pi);
+  end
 catch
     try
         lerror=lasterror;