From 3881ae73f2ea70090eb5373b2431b36b9236d5f6 Mon Sep 17 00:00:00 2001
From: Tim Quatmann <tim.quatmann@cs.rwth-aachen.de>
Date: Wed, 6 Nov 2019 15:24:19 +0100
Subject: [PATCH] glpk: Fixed pop()ing for the case where no constraints have
 to be deleted.

---
 src/storm/solver/GlpkLpSolver.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/storm/solver/GlpkLpSolver.cpp b/src/storm/solver/GlpkLpSolver.cpp
index 68a34e57a..170d55a78 100644
--- a/src/storm/solver/GlpkLpSolver.cpp
+++ b/src/storm/solver/GlpkLpSolver.cpp
@@ -430,7 +430,9 @@ namespace storm {
                 IncrementalLevel const& lvl = incrementalData.back();
                 // Since glpk uses 1-based indexing, we need to prepend an additional index
                 std::vector<int> indicesToBeRemoved = storm::utility::vector::buildVectorForRange(lvl.firstConstraintIndex - 1, glp_get_num_rows(this->lp) + 1);
-                glp_del_rows(this->lp, indicesToBeRemoved.size() - 1, indicesToBeRemoved.data());
+                if (indicesToBeRemoved.size() > 1) {
+                    glp_del_rows(this->lp, indicesToBeRemoved.size() - 1, indicesToBeRemoved.data());
+                }
                 indicesToBeRemoved.clear();
                 
                 if (!lvl.variables.empty()) {