Adding upstream version 15.5.upstream/15.5

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 92 insertions, 0 deletions

diff --git a/src/backend/optimizer/geqo/geqo_recombination.c b/src/backend/optimizer/geqo/geqo_recombination.c
new file mode 100644
index 0000000..a5d3e47
--- /dev/null
+++ b/src/backend/optimizer/geqo/geqo_recombination.c
@@ -0,0 +1,92 @@
+/*------------------------------------------------------------------------
+*
+* geqo_recombination.c
+*	 misc recombination procedures
+*
+* src/backend/optimizer/geqo/geqo_recombination.c
+*
+*-------------------------------------------------------------------------
+*/
+
+/* contributed by:
+   =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
+   *  Martin Utesch				 * Institute of Automatic Control	   *
+   =							 = University of Mining and Technology =
+   *  utesch@aut.tu-freiberg.de  * Freiberg, Germany				   *
+   =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
+ */
+
+/* -- parts of this are adapted from D. Whitley's Genitor algorithm -- */
+
+#include "postgres.h"
+
+#include "optimizer/geqo_random.h"
+#include "optimizer/geqo_recombination.h"
+
+
+/*
+ * init_tour
+ *
+ *	 Randomly generates a legal "traveling salesman" tour
+ *	 (i.e. where each point is visited only once.)
+ */
+void
+init_tour(PlannerInfo *root, Gene *tour, int num_gene)
+{
+	int			i,
+				j;
+
+	/*
+	 * We must fill the tour[] array with a random permutation of the numbers
+	 * 1 .. num_gene.  We can do that in one pass using the "inside-out"
+	 * variant of the Fisher-Yates shuffle algorithm.  Notionally, we append
+	 * each new value to the array and then swap it with a randomly-chosen
+	 * array element (possibly including itself, else we fail to generate
+	 * permutations with the last city last).  The swap step can be optimized
+	 * by combining it with the insertion.
+	 */
+	if (num_gene > 0)
+		tour[0] = (Gene) 1;
+
+	for (i = 1; i < num_gene; i++)
+	{
+		j = geqo_randint(root, i, 0);
+		/* i != j check avoids fetching uninitialized array element */
+		if (i != j)
+			tour[i] = tour[j];
+		tour[j] = (Gene) (i + 1);
+	}
+}
+
+/* city table is used in these recombination methods: */
+#if defined(CX) || defined(PX) || defined(OX1) || defined(OX2)
+
+/* alloc_city_table
+ *
+ *	 allocate memory for city table
+ */
+City *
+alloc_city_table(PlannerInfo *root, int num_gene)
+{
+	City	   *city_table;
+
+	/*
+	 * palloc one extra location so that nodes numbered 1..n can be indexed
+	 * directly; 0 will not be used
+	 */
+	city_table = (City *) palloc((num_gene + 1) * sizeof(City));
+
+	return city_table;
+}
+
+/* free_city_table
+ *
+ *	  deallocate memory of city table
+ */
+void
+free_city_table(PlannerInfo *root, City * city_table)
+{
+	pfree(city_table);
+}
+
+#endif							/* CX || PX || OX1 || OX2 */