Matrix Factorization Save

Matrix factorization save = {0 | 1}

Description / Usage

This optional card is a boolean specification that determines whether the preconditioner factorization information should be kept after a solve. Valid options are

0

Factorization information is discarded.

1

Factorization information is kept for that step.

If the Matrix factorization save card is omitted, then the default selection is 0.

Examples

Following is a sample card:

Matrix factorization save = 1

Technical Discussion

This option is most useful for iterative solution techniques where the computed preconditioning matrix found from an incomplete factorization requires significant computational resources. Such a preconditioner may be useful in later matrix solves and obviate the need to compute another expensive preconditioner at the later stage. Although a lot of time may be saved by re-using a previous factorization, the loss in accuracy may cause convergence problems.