The technique of watching two literals per clause to determine when a clause becomes a unit clause was introduced recently in the Chaff satisfiability program. That program does not perform either equivalent-literal detection or binary-clause detection. We describe a generalization of the technique that handles the tracking necessary to support equivalent-literal detection and binary-clause det...

Constraint satisfaction and propositional satisfiability problems are often solved using backtracking search. Previous studies have shown that a technique called randomization and restarts can dramatically improve the performance of a backtracking algorithm on some instances. We consider the commonly occurring scenario where one is to solve an ensemble of instances using a backtracking algorith...

Backtracking search is often the method of choice for solving constraint satisfaction and propositional satisfiability problems. Previous studies have shown that portfolios of backtracking algorithms—a selection of one or more algorithms plus a schedule for executing the algorithms—can dramatically improve performance on some instances. In this paper, we consider a setting that often arises in ...

In this paper, we construct a new approach of affine scaling interior algorithm using the affine scaling conjugate gradient and Lanczos methods for bound constrained nonlinear optimization. We get the iterative direction by solving quadratic model via affine scaling conjugate gradient and Lanczos methods. By using the line search backtracking technique, we will find an acceptable trial step len...

The popular use of backtracking as a control strategy for theorem proving in PROLOG and in Truth-MaintenanceSystems (TMS) led to increased interest in various schemes for enhancing the efficiency of backtrack search. Researchers have referred to these enhancement schemes by the names ‘ ‘Intelligent Backtracking’ ’ (in PROLOG), ‘ ‘Dependencydirected-backtracking” (in TMS) and others. Those impro...