Constraint-Directed Backtracking Algorithm for Constraint-Satisfaction Problems
نویسندگان
چکیده
We propose a new backtracking method called constraint-directed backtracking (CDBT) for solving constraint-satisfaction problems (CSPs). CDBT and chronological back-tracking (BT) share a similar style of instantiating variables (forward) and re-instantiating variables (backward). They diier in that CDBT searches instantiations of variables in a variable set from a given constraint posed on that variable set and appends it to a partial solution, whereas BT searches the instantiation of one variable from its domain. The search space of CDBT is much more limited than that of chronological backtracking. The similarity between CDBT and BT enables us to incorporate other tree search techniques, such as BJ, CBJ, FC, into CDBT to improve its performance further.
منابع مشابه
A New Method for Solving Constraint Satisfaction Problems
Many important problems in Artificial Intelligence can be defined as Constraint Satisfaction Problems (CSP). These types of problems are defined by a limited set of variables, each having a limited domain and a number of Constraints on the values of those variables (these problems are also called Consistent Labeling Problems (CLP), in which “Labeling means assigning a value to a variable.) Solu...
متن کاملA New Method for Solving Constraint Satisfaction Problems
Many important problems in Artificial Intelligence can be defined as Constraint Satisfaction Problems (CSP). These types of problems are defined by a limited set of variables, each having a limited domain and a number of Constraints on the values of those variables (these problems are also called Consistent Labeling Problems (CLP), in which “Labeling" means assigning a value to a variable.) Sol...
متن کاملBacktracking Algorithms for Constraint Satisfaction Problems { a Tutorial Survey
Over the past twenty years a number of backtracking algorithms for constraint satisfaction problems have been developed. This survey describes the basic backtrack search within the search space framework and then presents a number of improvements including look-back methods such as backjumping, constraint recording, backmarking, and look-ahead methods such as forward checking and dynamic variab...
متن کاملBacktracking Algorithms for Constraint Satisfaction Problems { a Survey
Over the past twenty years, a number of backtracking algorithms for constraint satisfaction problems, have been developed. This survey describes the basic backtrack search within the search space framework and then presents a number of improvements including look-back methods such as backjumping, constraint recording, backmarking, and look-ahead methods such as, forward checking, and dynamic va...
متن کاملIntelligent Backtracking on the Hardest Constraint Problems
A number of researchers have presented evidence that the hardest constraint satisfaction problems tend to arise near the \crossover" point, where around half the problems have solutions. Two recent papers , however, argue that while this is true of the median search cost, the mean search cost has an entirely diierent behavior. The mean search cost appears to be dominated by a relatively small n...
متن کامل