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Center for Nonlinear Studies |
The iterative solution of series of linear and nonlinear systems arising in unsteady fluid flow simulation is considered. The focus is made on the appropriate choice of the initial guess. The computation of a better initial guess for two iterative linear system solvers (GCR and GMRES) is based on the history of the evolution problem solving. For implicitly discretized nonlinear evolution problems, a reduced model technique is developed for computing a better initial guess for the inexact Newton method. The computational effect of the chosen initial guess is compared with that of the standard (physically motivated) initial guess.