Unshare variables for maximum_arg / minimum_arg constraints. Fixes #169.

Gecode · Aug 31, 2023 · ecf84ec · ecf84ec
1 parent 34adb07
commit ecf84ec
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diff --git a/changelog.in b/changelog.in
@@ -69,6 +69,14 @@ Date: 2020-??-??
 [DESCRIPTION]
 Let's see.
 
+[ENTRY]
+Module: flatzinc
+What:   bug
+Issue:  169
+Rank:   minor
+[DESCRIPTION]
+Unshare variables for maximum_arg / minimum_arg constraints.
+
 [ENTRY]
 Module: int
 What:   bug

diff --git a/gecode/flatzinc/registry.cpp b/gecode/flatzinc/registry.cpp
@@ -1120,25 +1120,31 @@ namespace Gecode { namespace FlatZinc {
     }
 
     void p_minimum_arg(FlatZincSpace& s, const ConExpr& ce, AST::Node* ann) {
-      IntVarArgs iv = s.arg2intvarargs(ce[0]);
+      IntVar x = s.arg2IntVar(ce[2]);
+      IntVarArgs iv = x + s.arg2intvarargs(ce[0]);
+      unshare(s, iv);
       int offset = ce[1]->getInt();
-      argmin(s, iv, offset, s.arg2IntVar(ce[2]), true, s.ann2ipl(ann));
+      argmin(s, iv.slice(1), offset, x, true, s.ann2ipl(ann));
     }
 
     void p_maximum_arg(FlatZincSpace& s, const ConExpr& ce, AST::Node* ann) {
-      IntVarArgs iv = s.arg2intvarargs(ce[0]);
+      IntVar x = s.arg2IntVar(ce[2]);
+      IntVarArgs iv = x + s.arg2intvarargs(ce[0]);
+      unshare(s, iv);
       int offset = ce[1]->getInt();
-      argmax(s, iv, offset, s.arg2IntVar(ce[2]), true, s.ann2ipl(ann));
+      argmax(s, iv.slice(1), offset, x, true, s.ann2ipl(ann));
     }
 
     void p_minimum_arg_bool(FlatZincSpace& s, const ConExpr& ce, AST::Node* ann) {
       BoolVarArgs bv = s.arg2boolvarargs(ce[0]);
+      unshare(s, bv);
       int offset = ce[1]->getInt();
       argmin(s, bv, offset, s.arg2IntVar(ce[2]), true, s.ann2ipl(ann));
     }
 
     void p_maximum_arg_bool(FlatZincSpace& s, const ConExpr& ce, AST::Node* ann) {
       BoolVarArgs bv = s.arg2boolvarargs(ce[0]);
+      unshare(s, bv);
       int offset = ce[1]->getInt();
       argmax(s, bv, offset, s.arg2IntVar(ce[2]), true, s.ann2ipl(ann));
     }