SNESConvergedCorrectPressure#

Convergence test that adds a vector in the nullspace to make the continuum integral of the pressure field equal to zero. This is normally used only to evaluate convergence rates for the pressure accurately. The convergence test itself just mimics SNESConvergedDefault().

Synopsis#

#include "petscdmplex.h" 
#include "petscsnes.h"   
PetscErrorCode SNESConvergedCorrectPressure(SNES snes, PetscInt it, PetscReal xnorm, PetscReal gnorm, PetscReal f, SNESConvergedReason *reason, void *ctx)

Logically Collective

Input Parameters#

snes - the SNES context
it - the iteration (0 indicates before any Newton steps)
xnorm - 2-norm of current iterate
snorm - 2-norm of current step
fnorm - 2-norm of function at current iterate
ctx - Optional user context

Output Parameter#

reason - SNES_CONVERGED_ITERATING, SNES_CONVERGED_ITS, or SNES_DIVERGED_FNORM_NAN

Options Database Key#

-snes_convergence_test correct_pressure - see SNESSetFromOptions()

Notes#

In order to use this convergence test, you must set up several PETSc structures. First fields must be added to the DM, and a PetscDS must be created with discretizations of those fields. We currently assume that the pressure field has index 1. The pressure field must have a nullspace, likely created using the DMSetNullSpaceConstructor() interface. Last we must be able to integrate the pressure over the domain, so the DM attached to the SNES must be a DMPLEX at this time.