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Select the Solver
Creo Simulate uses one of two solvers in an analysis or design study. You can use either the direct solver or the iterative solver. The direct solver and the iterative solver are different methods by which Creo Simulate solves systems of simultaneous equations that arise from the geometric element model.
Creo Simulate uses the direct solver by default because it usually requires less time, disk space, and/or memory than the iterative solver. You should use the direct solver in the following situations:
if your model has thin features
if your model did not converge using the iterative solver
if your design study contains any analyses other than linear static, such as contact, modal, or transient thermal
if your model is insufficiently constrained or you want to locate constraint problems in your model. For more information, see Insufficiently Constrained Models.
If you want to try the iterative solver, you should monitor how much time and disk space your models take to run with each type of solver. In this way, you can determine which solver is best for which type of model.
 
* For jobs running the direct solver, an elapsed time/CPU time ratio much greater than 4 may indicate a problem. For jobs running the iterative solver, a ratio much greater than 7 may indicate a problem. The iterative solver generally has a higher ratio of elapsed to CPU time because it does more I/O per calculation than the direct solver.