#include "petscsnes.h" PetscErrorCode SNESQNSetScaleType(SNES snes, SNESQNScaleType stype)Logically Collective on SNES
| snes | - the iterative context | |
| stype | - scale type |
| -snes_qn_scale_type <diagonal,none,scalar,jacobian> |
| SNES_QN_SCALE_NONE | - don't scale the problem | |
| SNES_QN_SCALE_SCALAR | - use shanno scaling | |
| SNES_QN_SCALE_DIAGONAL | - scale with a diagonalized BFGS formula (see Gilbert and Lemarechal 1989), available | |
| SNES_QN_SCALE_JACOBIAN | - scale by solving a linear system coming from the Jacobian you provided with SNESSetJacobian() computed at the first iteration of QN and at ever restart. |