Switch from std::shuffle to std::random_shuffle

YAPB++/source/search/search.hpp

@@ -11,6 +11,9 @@ template<bool firstbranch>
 bool doSearchBranch(const SearchOptions& so, Problem* p, SolutionStore* ss,
                     RBase* rbase, TraceFollowingQueue* tfq, int depth)
 {
+    std::minstd_rand rd;
+    static std::default_random_engine rng(rd());
+
     info_out(1, "search depth: " << depth);
     info_out(2, "Current partition: " <<  p->p_stack.dumpCurrentPartition());
     if(depth > rbase->depth())
@@ -41,7 +44,7 @@ bool doSearchBranch(const SearchOptions& so, Problem* p, SolutionStore* ss,
         orderCell(firstbranch ? cell.begin() + 1 : cell.begin(),
                   cell.end(),
                   firstbranch ? so.heuristic.search_first_branch_value : so.heuristic.search_value,
-                  rbase);
+                  rbase, rng);
 
         for(int i : range1(cell.size()))
         {
@@ -127,7 +130,7 @@ SolutionStore doSearch(Problem* p, const std::vector<AbstractConstraint*>& cons,
         try {
             doSearchBranch<true>(so, p, &solutions, rb, &tfq, 1);
         }
-        catch(const EndOfSearch&) { 
+        catch(const EndOfSearch&) {
             debug_out(1, "search", "Node limit reached!");
         }
     }

YAPB++/source/search/search_common.hpp

@@ -9,6 +9,8 @@
 #include "library/stats.hpp"
 #include "library/perm.hpp"
 
+#include <random>
+
 // Checks a solution satisfies all the constraints, and
 // adds to the solutionStore if it is. Returns true if
 // the solution is real
@@ -32,7 +34,7 @@ bool handlePossibleSolution(Problem* p, SolutionStore* ss, RBase* rbase)
 // Orders a cell of a partition stack according to a given heuristic
 
 template<typename It>
-void orderCell(It begin, It end, SearchHeuristic sh, RBase* rbase)
+void orderCell(It begin, It end, SearchHeuristic sh, RBase* rbase, std::default_random_engine& rng)
 {
     switch(sh)
     {
@@ -45,7 +47,7 @@ void orderCell(It begin, It end, SearchHeuristic sh, RBase* rbase)
                 ReverseSorter(IndirectSorter([&](auto i) -> auto& { return (rbase->inv_value_ordering)[i]; })));
             return;
         case SearchBranch_Random:
-            std::random_shuffle(begin, end);
+            std::shuffle(begin, end, rng);
             return;
         case SearchBranch_Sorted:
             std::sort(begin, end);