# SNESSetConvergenceHistory#

Sets the array used to hold the convergence history.

## Synopsis#

#include "petscsnes.h"
PetscErrorCode SNESSetConvergenceHistory(SNES snes, PetscReal a[], PetscInt its[], PetscInt na, PetscBool reset)


Logically Collective

## Input Parameters#

• snes - iterative context obtained from SNESCreate()

• a - array to hold history, this array will contain the function norms computed at each step

• its - integer array holds the number of linear iterations for each solve.

• na - size of a and its

• reset - PETSC_TRUE indicates each new nonlinear solve resets the history counter to zero, else it continues storing new values for new nonlinear solves after the old ones

## Notes#

If ‘a’ and ‘its’ are NULL then space is allocated for the history. If ‘na’ PETSC_DECIDE or PETSC_DEFAULT then a default array of length 10000 is allocated.

This routine is useful, e.g., when running a code for purposes of accurate performance monitoring, when no I/O should be done during the section of code that is being timed.

SNES, SNESSolve(), SNESGetConvergenceHistory()