Merge in GEQO Optimizer

From: "Martin S. Utesch" <utesch@aut.tu-freiberg.de>

src/backend/optimizer/geqo/geqo_pool.c

@@ -0,0 +1,248 @@
+/*------------------------------------------------------------------------
+ *
+ * geqo_pool.c--
+ *    Genetic Algorithm (GA) pool stuff
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ * $Id: geqo_pool.c,v 1.1 1997/02/19 12:57:31 scrappy Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/* 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 "nodes/pg_list.h"
+#include "nodes/relation.h"
+#include "nodes/primnodes.h"
+
+#include "utils/palloc.h"
+#include "utils/elog.h"
+
+#include "optimizer/internal.h"
+#include "optimizer/paths.h"
+#include "optimizer/pathnode.h"
+#include "optimizer/clauses.h"
+#include "optimizer/cost.h"
+
+#include "lib/qsort.h"
+
+#include "optimizer/geqo_gene.h"
+#include "optimizer/geqo.h"
+#include "optimizer/geqo_pool.h"
+#include "optimizer/geqo_copy.h"
+#include "optimizer/geqo_recombination.h"
+
+
+static int compare(void *arg1, void *arg2);
+
+/*
+ * alloc-pool--
+ * 	allocates memory for GA pool
+ */
+Pool *
+alloc_pool(int pool_size, int string_length)
+{
+ Pool *new_pool;
+ Chromosome *chromo;
+ int i;
+
+ /* pool */
+ new_pool = (Pool *) palloc (sizeof(Pool));
+ new_pool->size = (int) pool_size;
+ new_pool->string_length = (int) string_length;
+
+ /* all chromosome */
+ new_pool->data = (Chromosome *) palloc (pool_size * sizeof(Chromosome));
+
+ /* all gene */
+ chromo = (Chromosome *) new_pool->data; /* vector of all chromos */
+ for (i=0; i<pool_size; i++) {
+	chromo[i].string = palloc((string_length+1)*sizeof(Gene));
+	}
+
+ return (new_pool);
+}
+
+/*
+ * free-pool--
+ * 	deallocates memory for GA pool
+ */
+void
+free_pool (Pool *pool)
+{
+ Chromosome *chromo;
+ int i;
+
+ /* all gene */
+ chromo = (Chromosome *) pool->data; /* vector of all chromos */
+ for (i=0; i<pool->size; i++) pfree(chromo[i].string);
+
+ /* all chromosome */
+ pfree (pool->data);
+
+ /* pool */
+ pfree (pool);
+}
+
+/*
+ * random-init-pool--
+ * 	initialize genetic pool
+ */
+void
+random_init_pool (Query *root, Pool *pool, int strt, int stp)
+{
+ Chromosome *chromo = (Chromosome *) pool->data;
+ int i;
+
+ for (i=strt; i<stp; i++) {
+	init_tour(chromo[i].string, pool->string_length); /* from "geqo_recombination.c" */
+
+	pool->data[i].worth = 
+		geqo_eval(root, chromo[i].string, pool->string_length); /* "from geqo_eval.c" */
+	}
+}
+
+/*
+ * sort-pool--
+ *   sorts input pool according to worth, from smallest to largest
+ *
+ *   maybe you have to change compare() for different ordering ...
+ */
+void
+sort_pool(Pool *pool)
+{ 
+ pg_qsort(pool->data, pool->size, sizeof(Chromosome), compare);
+
+}
+
+/*
+ * compare--
+ *   static input function for pg_sort
+ *
+ *   return values for sort from smallest to largest are prooved!
+ *   don't change them!
+ */
+static int
+compare(void *arg1, void *arg2)
+{
+    Chromosome chromo1 = *(Chromosome *) arg1;
+    Chromosome chromo2 = *(Chromosome *) arg2;
+
+    if (chromo1.worth == chromo2.worth)
+	return(0);
+    else if (chromo1.worth > chromo2.worth)
+	return(1);
+    else
+	return(-1);
+}
+
+/* alloc_chromo--
+ *    allocates a chromosome and string space
+ */
+Chromosome *
+alloc_chromo (int string_length)
+{
+ Chromosome *chromo;
+
+ chromo = (Chromosome *) palloc (sizeof(Chromosome));
+ chromo->string = (Gene *) palloc ((string_length+1)*sizeof(Gene));
+    
+ return (chromo);
+}
+
+/* free_chromo--
+ *    deallocates a chromosome and string space
+ */
+void
+free_chromo (Chromosome *chromo)
+{
+ pfree(chromo->string);
+ pfree(chromo);
+}
+
+/* spread_chromo--
+ *   inserts a new chromosome into the pool, displacing worst gene in pool
+ *   assumes best->worst = smallest->largest
+ */
+void
+spread_chromo (Chromosome *chromo, Pool *pool)
+{
+ int top, mid, bot;
+ int i, index;
+ Chromosome swap_chromo, tmp_chromo;
+
+ /* new chromo is so bad we can't use it */
+ if (chromo->worth > pool->data[pool->size-1].worth) return;
+
+ /* do a binary search to find the index of the new chromo */
+
+ top = 0;
+ mid = pool->size/2;
+ bot = pool->size-1;
+ index = -1;      
+
+ while (index == -1) {
+     /* these 4 cases find a new location */
+
+     if (chromo->worth <= pool->data[top].worth)
+        index = top;
+     else
+     if (chromo->worth == pool->data[mid].worth)
+        index = mid;
+     else
+     if (chromo->worth == pool->data[bot].worth)
+        index = bot;
+     else
+     if (bot-top <=1)
+        index = bot;
+
+
+     /* these 2 cases move the search indices since
+        a new location has not yet been found. */
+
+     else
+	  if (chromo->worth < pool->data[mid].worth) {
+         bot = mid;
+         mid = top + ( (bot-top)/2 );
+        }
+     else { /* (chromo->worth > pool->data[mid].worth) */
+         top = mid;
+         mid = top + ( (bot-top)/2 );
+        }
+    } /* ... while */
+
+ /* now we have index for chromo */
+
+ /* move every gene from index on down
+    one position to make room for chromo */
+
+  /* copy new gene into pool storage;
+     always replace worst gene in pool */
+
+  geqo_copy (&pool->data[pool->size-1], chromo, pool->string_length);
+
+  swap_chromo.string = pool->data[pool->size-1].string;
+  swap_chromo.worth  = pool->data[pool->size-1].worth;
+
+  for (i=index; i<pool->size; i++) {
+      tmp_chromo.string = pool->data[i].string;
+      tmp_chromo.worth  = pool->data[i].worth;
+
+      pool->data[i].string = swap_chromo.string;
+      pool->data[i].worth  = swap_chromo.worth;
+
+      swap_chromo.string = tmp_chromo.string;
+      swap_chromo.worth  = tmp_chromo.worth;
+     }
+}