petsc-3.14.5 2021-03-03
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# MatLMVMSymBroydenSetScaleType

Sets the scale type for symmetric Broyden-type updates.

### Synopsis

    #include "petscksp.h"
    PetscErrorCode MatLMVMSymBroydenSetScaleType(Mat B, MatLMVMSymBroydenScaleType stype)

### Input Parameters

| snes | - the iterative context
| rtype | - restart type

### Options Database

| -mat_lmvm_scale_type <none,scalar,diagonal> | - set the scaling type

### MatLMVMSymBrdnScaleTypes

| MAT_LMVM_SYMBROYDEN_SCALE_NONE | - initial Hessian is the identity matrix
| MAT_LMVM_SYMBROYDEN_SCALE_SCALAR | - use the Shanno scalar as the initial Hessian
| MAT_LMVM_SYMBROYDEN_SCALE_DIAGONAL | - use a diagonalized BFGS update as the initial Hessian

### See Also

MATLMVMSYMBROYDEN, MatCreateLMVMSymBroyden()

### Level

intermediate

### Location

src/ksp/ksp/utils/lmvm/symbrdn/symbrdn.c
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages