# DAAppUseMultigrid

Set the preconditioner for the linear solver to be an algebraic multigrid.

## Synopsis

    int DAAppUseMultigrid(TAO_APPLICATION daapplication, int coarselevel)

Collective on TAO_APPLICATION

## Input Parameters

| daapplication | - the DA Application object
| coarselevel | - the coarsest grid to be used in the multigrid preconditioner. (Grid 0 is the coarsest grid.

## Options Database Key

| -tao_da_multigrid | - use multigrid linear solver
| -ksp_view | - view the linear solver

## Note

This function should be called after DAAppSetHessianRoutine();

## Note

This function should be called before each optimization solver as part of the DAAppMonitor

## Note

Multigrid functionality is still under developement for good performance.

## See Also

TaoGetKSP(), DAAppSetupMultigrid()

## Options Database Key

-tao_da_multigrid -

## Keywords

Linear Solver, Multigrid, DA, KSP

Level:intermediate
Location:src/petsctao/gridapplication/multigrid/daapp_mgrid.c
TAO DA Application Index
Table of Contents