Improving parallel performance of large-scale watershed simulations

A comprehensive, physics-based watershed model with multispatial domains and multitemporal scales has been developed and used. This paper discusses interfacing the watershed model with PETSc and evaluating the model performance for a variety of PETSc preconditioners. Both wall-clock time and scalability are compared based on performance on the Cray XT4 machine, along with tests to verify that all solutions are producing accurate results. The findings conclude that the PETSc Conjugate Gradient solver and preconditioners outperform the simple Conjugate Gradient solver and Jacobi preconditioner originally used by the watershed model. Tests show that the HypreBoomeramg preconditioner provides the most significant speedup for the watershed model.