SNESQNScaleType#

the scaling type used by SNESQN

Values#

  • 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 SNESQN and at ever restart.

Options Database Key#

  • -snes_qn_scale_type <diagonal,none,scalar,jacobian> - Scaling type

See Also#

SNES, SNESQN, SNESQNSetScaleType(), SNESQNType, SNESQNSetType(), SNESQNSetRestartType(), SNESQNRestartType`

Level#

intermediate

Location#

include/petscsnes.h

Index of all SNES routines
Table of Contents for all manual pages
Index of all manual pages