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# PCAMGX
Interface to NVIDIA's AmgX algebraic multigrid 
## Options Database Keys

- ***-pc_amgx_amg_method <CLASSICAL,AGGREGATION> -*** set the AMG algorithm to use
- ***-pc_amgx_amg_cycle <V,W,F,CG> -*** set the AMG cycle type
- ***-pc_amgx_smoother <PCG,PCGF,PBICGSTAB,GMRES,FGMRES,JACOBI_L1,BLOCK_JACOBI,GS,MULTICOLOR_GS,MULTICOLOR_ILU,MULTICOLOR_DILU,CHEBYSHEV_POLY,NOSOLVER> -*** set the AMG pre/post smoother
- ***-pc_amgx_jacobi_relaxation_factor -*** set the relaxation factor for Jacobi smoothing
- ***-pc_amgx_gs_symmetric -*** enforce symmetric Gauss-Seidel smoothing (only applies if GS smoothing is selected)
- ***-pc_amgx_selector <SIZE_2,SIZE_4,SIZE_8,MULTI_PAIRWISE,PMIS,HMIS> -*** set the AMG coarse selector
- ***-pc_amgx_presweeps -*** set the number of AMG pre-sweeps
- ***-pc_amgx_postsweeps -*** set the number of AMG post-sweeps
- ***-pc_amgx_max_levels -*** set the maximum number of levels in the AMG level hierarchy
- ***-pc_amgx_strength_threshold -*** set the strength threshold for the AMG coarsening
- ***-pc_amgx_aggressive_levels -*** set the number of levels (from the finest) that should apply aggressive coarsening
- ***-pc_amgx_coarse_solver <DENSE_LU_SOLVER,NOSOLVER> -*** set the coarse solve
- ***-pc_amgx_print_grid_stats -*** output the AMG grid hierarchy to stdout
- ***-pc_amgx_verbose -*** enable AmgX output





## Note
Implementation will accept host or device pointers, but good performance will require that the `KSP` is also GPU accelerated so that data is not frequently transferred between host and device.


## See Also
 `PCGAMG`, `PCHYPRE`, `PCMG`, `PCAmgXGetResources()`, `PCCreate()`, `PCSetType()`, `PCType` (for list of available types), `PC`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/amgx/amgx.cxx.html#PCAMGX">src/ksp/pc/impls/amgx/amgx.cxx</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ksp/pc/impls/amgx/amgx.cxx)


[Index of all PC routines](index.md)  
[Table of Contents for all manual pages](/manualpages/index.md)  
[Index of all manual pages](/manualpages/singleindex.md)