MatLMVMSymBroydenGetPhi#
Get the phi parameter for a Broyden class quasi-Newton update matrix
Synopsis#
#include "petscksp.h"
PetscErrorCode MatLMVMSymBroydenGetPhi(Mat B, PetscReal *phi)
Input Parameter#
B - The matrix
Output Parameter#
phi - a number defining an update that is an affine combination of the BFGS update (phi = 0) and DFP update (phi = 1)
Note#
If B does not have a constant value of phi for all iterations this will
return phi = PETSC_DETERMINE = -1, a negative value that phi cannot
attain for a valid general Broyden update.
This is the case if B is a MATLMVMSYMBADBROYDEN, where phi’s dual value
psi is constant and phi changes from iteration to iteration.
See Also#
KSP: Linear System Solvers,
MATLMVMSYMBROYDEN, MATLMVMSYMBADBROYDEN,
MATLMVMDFP, MATLMVMBFGS,
MatLMVMSymBroydenSetPhi(),
MatLMVMSymBadBroydenGetPsi(), MatLMVMSymBadBroydenSetPsi()
Level#
advanced
Location#
src/ksp/ksp/utils/lmvm/symbrdn/symbrdn.c
Index of all KSP routines
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