crstrtgy.c

clips源代码

   /*******************************************************/
   /*      "C" Language Integrated Production System      */
   /*                                                     */
   /*             CLIPS Version 6.30  10/19/06            */
   /*                                                     */
   /*         CONFLICT RESOLUTION STRATEGY MODULE         */
   /*******************************************************/

/*************************************************************/
/* Purpose: Used to determine where a new activation is      */
/*   placed on the agenda based on the current conflict      */
/*   resolution strategy (depth, breadth, mea, lex,          */
/*   simplicity, or complexity). Also provides the           */
/*   set-strategy and get-strategy commands.                 */
/*                                                           */
/* Principal Programmer(s):                                  */
/*      Gary D. Riley                                        */
/*                                                           */
/* Contributing Programmer(s):                               */
/*                                                           */
/* Revision History:                                         */
/*      6.23: Corrected compilation errors for files         */
/*            generated by constructs-to-c. DR0861           */
/*                                                           */
/*      6.24: Removed CONFLICT_RESOLUTION_STRATEGIES         */
/*            compilation flag.                              */
/*                                                           */
/*      6.30: Added salience groups to improve performance   */
/*            with large numbers of activations of different */
/*            saliences.                                     */
/*                                                           */
/*            Removed pseudo-facts used for not CEs.         */
/*                                                           */
/*************************************************************/

#define _CRSTRTGY_SOURCE_

#include <stdio.h>
#define _STDIO_INCLUDED_
#include <string.h>

#include "setup.h"

#if DEFRULE_CONSTRUCT

#include "constant.h"
#include "pattern.h"
#include "reteutil.h"
#include "argacces.h"
#include "agenda.h"
#include "envrnmnt.h"
#include "memalloc.h"

#include "crstrtgy.h"

#define GetMatchingItem(x,i) ((x->basis->binds[i].gm.theMatch != NULL) ? \
                              (x->basis->binds[i].gm.theMatch->matchingItem) : NULL)

/***************************************/
/* LOCAL INTERNAL FUNCTION DEFINITIONS */
/***************************************/

   static ACTIVATION             *PlaceDepthActivation(ACTIVATION *,struct salienceGroup *);
   static ACTIVATION             *PlaceBreadthActivation(ACTIVATION *,struct salienceGroup *);
   static ACTIVATION             *PlaceLEXActivation(void *,ACTIVATION *,struct salienceGroup *);
   static ACTIVATION             *PlaceMEAActivation(void *,ACTIVATION *,struct salienceGroup *);
   static ACTIVATION             *PlaceComplexityActivation(ACTIVATION *,struct salienceGroup *);
   static ACTIVATION             *PlaceSimplicityActivation(ACTIVATION *,struct salienceGroup *);
   static ACTIVATION             *PlaceRandomActivation(ACTIVATION *,struct salienceGroup *);
   static int                     ComparePartialMatches(void *,ACTIVATION *,ACTIVATION *);
   static char                   *GetStrategyName(int);
   static unsigned long long     *SortPartialMatch(void *,struct partialMatch *);
   
/******************************************************************/
/* PlaceActivation: Coordinates placement of an activation on the */
/*   Agenda based on the current conflict resolution strategy.    */
/******************************************************************/
globle void PlaceActivation(
  void *theEnv,
  ACTIVATION **whichAgenda,
  ACTIVATION *newActivation,
  struct salienceGroup *theGroup)
  {
   ACTIVATION *placeAfter = NULL;

   /*================================================*/
   /* Set the flag which indicates that a change has */
   /* been made to the agenda.                       */
   /*================================================*/

   EnvSetAgendaChanged(theEnv,TRUE);

   /*=============================================*/
   /* Determine the location where the activation */
   /* should be placed in the agenda based on the */
   /* current conflict resolution strategy.       */
   /*==============================================*/

   if (*whichAgenda != NULL) 
     {
      switch (AgendaData(theEnv)->Strategy)
        {
         case DEPTH_STRATEGY:
           placeAfter = PlaceDepthActivation(newActivation,theGroup);
           break;

         case BREADTH_STRATEGY:
           placeAfter = PlaceBreadthActivation(newActivation,theGroup);
           break;

         case LEX_STRATEGY:
           placeAfter = PlaceLEXActivation(theEnv,newActivation,theGroup);
           break;

         case MEA_STRATEGY:
           placeAfter = PlaceMEAActivation(theEnv,newActivation,theGroup);
           break;

         case COMPLEXITY_STRATEGY:
           placeAfter = PlaceComplexityActivation(newActivation,theGroup);
           break;

         case SIMPLICITY_STRATEGY:
           placeAfter = PlaceSimplicityActivation(newActivation,theGroup);
           break;

         case RANDOM_STRATEGY:
           placeAfter = PlaceRandomActivation(newActivation,theGroup);
           break;
        }
     } 
   else
     {
      theGroup->first = newActivation;
      theGroup->last = newActivation;
     }

   /*==============================================================*/
   /* Place the activation at the appropriate place in the agenda. */
   /*==============================================================*/

   if (placeAfter == NULL) /* then place it at the beginning of then agenda. */
     {
      newActivation->next = *whichAgenda;
      *whichAgenda = newActivation;
      if (newActivation->next != NULL) newActivation->next->prev = newActivation;
     }
   else /* insert it in the agenda. */
     {
      newActivation->next = placeAfter->next;
      newActivation->prev = placeAfter;
      placeAfter->next = newActivation;
      if (newActivation->next != NULL)
        { newActivation->next->prev = newActivation; }
     }
  }

/*******************************************************************/
/* PlaceDepthActivation: Determines the location in the agenda     */
/*    where a new activation should be placed for the depth        */
/*    strategy. Returns a pointer to the activation after which    */
/*    the new activation should be placed (or NULL if the          */
/*    activation should be placed at the beginning of the agenda). */
/*******************************************************************/
static ACTIVATION *PlaceDepthActivation(
  ACTIVATION *newActivation,
  struct salienceGroup *theGroup)
  {
   ACTIVATION *lastAct, *actPtr;
   unsigned long long timetag;
     
   /*============================================*/
   /* Set up initial information for the search. */
   /*============================================*/

   timetag = newActivation->timetag;
   if (theGroup->prev == NULL)
     { lastAct = NULL; }
   else
     { lastAct = theGroup->prev->last; }

   /*=========================================================*/
   /* Find the insertion point in the agenda. The activation  */
   /* is placed before activations of lower salience and      */
   /* after activations of higher salience. Among activations */
   /* of equal salience, the activation is placed before      */
   /* activations with an equal or lower timetag (yielding    */
   /* depth first traversal).                                 */
   /*=========================================================*/

   actPtr = theGroup->first;
   while (actPtr != NULL)
     {
      if (timetag < actPtr->timetag)
        {
         lastAct = actPtr;
         if (actPtr == theGroup->last)
           { break; }
         else 
           { actPtr = actPtr->next; }
        }
      else
        { break; }
     }

   /*========================================*/
   /* Update the salience group information. */
   /*========================================*/
   
   if ((lastAct == NULL) || 
       ((theGroup->prev != NULL) && (theGroup->prev->last == lastAct)))
     { theGroup->first = newActivation; }
     
   if ((theGroup->last == NULL) || (theGroup->last == lastAct))
     { theGroup->last = newActivation; }

   /*===========================================*/
   /* Return the insertion point in the agenda. */
   /*===========================================*/

   return(lastAct);
  }

/*******************************************************************/
/* PlaceBreadthActivation: Determines the location in the agenda   */
/*    where a new activation should be placed for the breadth      */
/*    strategy. Returns a pointer to the activation after which    */
/*    the new activation should be placed (or NULL if the          */
/*    activation should be placed at the beginning of the agenda). */
/*******************************************************************/
static ACTIVATION *PlaceBreadthActivation(
  ACTIVATION *newActivation,
  struct salienceGroup *theGroup)
  {
   unsigned long long timetag;
   ACTIVATION *lastAct, *actPtr;

   /*============================================*/
   /* Set up initial information for the search. */
   /*============================================*/

   timetag = newActivation->timetag;
   if (theGroup->last == NULL)
     {    
      if (theGroup->prev == NULL)
        { lastAct = NULL; }
      else
        { lastAct = theGroup->prev->last; }
     }
   else
     { lastAct = theGroup->last; }

   /*=========================================================*/
   /* Find the insertion point in the agenda. The activation  */
   /* is placed before activations of lower salience and      */
   /* after activations of higher salience. Among activations */
   /* of equal salience, the activation is placed after       */
   /* activations with a lessor timetag (yielding breadth     */
   /* first traversal).                                       */
   /*=========================================================*/

   actPtr = theGroup->last;
   while (actPtr != NULL)
     {
      if (timetag < actPtr->timetag)
        {
         if (actPtr == theGroup->first)
           {
            if (theGroup->prev == NULL)
              { lastAct = NULL; }
            else
              { lastAct = theGroup->prev->last; }
            break;
           }
         else 
           { actPtr = actPtr->prev; }
        }
      else
        {
         lastAct = actPtr; 
         break; 
        }
     }
     
   /*========================================*/
   /* Update the salience group information. */
   /*========================================*/
   
   if ((lastAct == NULL) || 
       ((theGroup->prev != NULL) && (theGroup->prev->last == lastAct)))
     { theGroup->first = newActivation; }
     
   if ((theGroup->last == NULL) || (theGroup->last == lastAct))
     { theGroup->last = newActivation; }

   /*===========================================*/
   /* Return the insertion point in the agenda. */
   /*===========================================*/

   return(lastAct);
  }

/*******************************************************************/
/* PlaceLEXActivation: Determines the location in the agenda       */
/*    where a new activation should be placed for the lex          */
/*    strategy. Returns a pointer to the activation after which    */
/*    the new activation should be placed (or NULL if the          */
/*    activation should be placed at the beginning of the agenda). */
/*******************************************************************/
static ACTIVATION *PlaceLEXActivation(
  void *theEnv,
  ACTIVATION *newActivation,
  struct salienceGroup *theGroup)
  {
   unsigned long long timetag;
   ACTIVATION *lastAct, *actPtr;
   int flag;

   /*============================================*/
   /* Set up initial information for the search. */
   /*============================================*/

   timetag = newActivation->timetag;
   if (theGroup->prev == NULL)
     { lastAct = NULL; }
   else
     { lastAct = theGroup->prev->last; }

   /*================================================*/
   /* Look first at the very end of the group to see */
   /* if the activation should be placed there.      */
   /*================================================*/
   
   actPtr = theGroup->last;
   if (actPtr != NULL)
     {
      flag = ComparePartialMatches(theEnv,actPtr,newActivation);
      
      if ((flag == LESS_THAN) ||
          ((flag == EQUAL) &&  (timetag > actPtr->timetag)))
        {
         theGroup->last = newActivation; 
         
         return(actPtr);
        }
     }
     
   /*=========================================================*/
   /* Find the insertion point in the agenda. The activation  */
   /* is placed before activations of lower salience and      */
   /* after activations of higher salience. Among activations */
   /* of equal salience, the OPS5 lex strategy is used for    */
   /* determining placement.                                  */
   /*=========================================================*/

   actPtr = theGroup->first;
   while (actPtr != NULL)
     {
      flag = ComparePartialMatches(theEnv,actPtr,newActivation);