petsc-3.14.5 2021-03-03
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# SNESNGMRESSetSelectType

Sets the selection type for SNESNGMRES. This determines how the candidate solution and combined solution are used to create the next iterate.

### Synopsis

    #include "petscsnes.h"
    PetscErrorCode SNESNGMRESSetSelectType(SNES snes,SNESNGMRESSelectType stype)

Logically Collective on SNES

### Input Parameters

| snes | - the iterative context
| stype | - selection type

### Options Database

| -snes_ngmres_select_type<difference,none,linesearch>

### SNESNGMRESSelectTypes

| SNES_NGMRES_SELECT_NONE | - choose the combined solution all the time
| SNES_NGMRES_SELECT_DIFFERENCE | - choose based upon the selection criteria
| SNES_NGMRES_SELECT_LINESEARCH | - choose based upon line search combination

### Notes

The default line search used is the L2 line search and it requires two additional function evaluations.

### Level

intermediate

### Location

src/snes/impls/ngmres/snesngmres.c

### Implementations

SNESNGMRESSetSelectType_NGMRES in src/snes/impls/ngmres/snesngmres.c
Index of all SNES routines
Table of Contents for all manual pages
Index of all manual pages