1. But

Factorize an assembled matrix or manufacture a pre-conditioning matrix.

The matrix produced by this operator is provided to operator RESOUDRE [U4.55.02] to solve linear systems.

This operator allows:

1. Or to factorize the assembled matrix (into a product of two triangular matrices) for direct methods,

2. Or to build a pre-conditioning matrix for iterative methods in order to accelerate convergence during resolution.

This command is a mandatory prerequisite before calling the RESOUDRE resolution command.

Produces (or enriches) a matr_asse data structure.