petsc-3.8.4 2018-03-24

SNESGetIterationNumber

Gets the number of nonlinear iterations completed at this time.

#include "petscsnes.h"  
PetscErrorCode  SNESGetIterationNumber(SNES snes,PetscInt *iter)

Not Collective

snes -SNES context

iter -iteration number

For example, during the computation of iteration 2 this would return 1.

This is useful for using lagged Jacobians (where one does not recompute the Jacobian at each SNES iteration). For example, the code

      ierr = SNESGetIterationNumber(snes,&it);
      if (!(it % 2)) {
        [compute Jacobian here]
      }

can be used in your ComputeJacobian() function to cause the Jacobian to be recomputed every second SNES iteration.

SNES, nonlinear, get, iteration, number,