From ecc4d022672db47e9367dc5aa23ddfcf2ab8ba24 Mon Sep 17 00:00:00 2001
From: Stuart Mitchell <hg@stuartmitchell.com>
Date: Mon, 7 Jan 2013 22:28:35 +1300
Subject: [PATCH] changes from Timo Korvola

---
 src/pulp/pulp.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/pulp/pulp.py b/src/pulp/pulp.py
index dc54444..3660983 100755
--- a/src/pulp/pulp.py
+++ b/src/pulp/pulp.py
@@ -360,10 +360,10 @@ class LpVariable(LpElement):
     def bounds(self, low, up):
         self.lowBound = low
         self.upBound = up
+        self.modified = True
 
     def positive(self):
-        self.lowBound = 0
-        self.upBound = None
+        self.bounds(0, None)
 
     def value(self):
         return self.varValue