Solving the Langford problem in parallel

Abstract

In this paper, the parallel resolution of the Langford problem is studied. Two different approaches are developed. First, an explicit construction of all the solutions is done using a shared memory. The application associated to this approach is written in C using the standard OpenMP library. Second, a parallelization of the algebraic method introduced by Godfrey is proposed. The application is taking advantage of MPI and has revealed efficient up to 128 processors. This solution opens up some new perspectives such as solving the already resolved instances of the problem more quickly and solving the next two open instances of the problem in a near future.