From 21a75358b1fa7104e7286a59ab0d9dd0a0db03c8 Mon Sep 17 00:00:00 2001
From: Mikael Zayenz Lagerkvist <lagerkvist@gecode.dev>
Date: Mon, 13 Jul 2026 17:09:23 +0200
Subject: [PATCH] Fix zero-cost edges in TSP example

---
 changelog.in     | 10 ++++++++++
 examples/tsp.cpp |  6 ------
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/changelog.in b/changelog.in
index 80921440fe..8e1d88ae49 100755
--- a/changelog.in
+++ b/changelog.in
@@ -116,6 +116,16 @@ Thanks: Yuri Victorovich
 Do not create empty MiniZinc directories when FlatZinc is disabled in an
 Autotools build.
 
+[ENTRY]
+Module: example
+What: bug
+Rank: minor
+Issue: 151
+Thanks: Ioannis Papatsoris
+[DESCRIPTION]
+Treat zero entries in the TSP example as valid zero-cost edges. This lets the
+br17 instance reach its optimum.
+
 [ENTRY]
 Module: flatzinc
 What:   new
diff --git a/examples/tsp.cpp b/examples/tsp.cpp
index 4344e13f5e..564026cbe3 100644
--- a/examples/tsp.cpp
+++ b/examples/tsp.cpp
@@ -244,12 +244,6 @@ class TSP : public IntMinimizeScript {
     // Cost matrix
     IntArgs c(n*n, p.d());
 
-    // Disallow disconnected nodes
-    for (int i=0; i<n; i++)
-      for (int j=0; j<n; j++)
-        if (p.d(i,j) == 0)
-          rel(*this, succ[i], IRT_NQ, j);
-
     // Cost of each edge
     IntVarArgs costs(*this, n, Int::Limits::min, Int::Limits::max);