SNESSetJacobian

Sets the function to compute Jacobian as well as the location to store the matrix.

Synopsis

#include "petscsnes.h"  
int SNESSetJacobian(SNES snes,Mat A,Mat B,int (*func)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void *ctx)
Collective on SNES and Mat

Input Parameters

snes - the SNES context
A - Jacobian matrix
B - preconditioner matrix (usually same as the Jacobian)
func - Jacobian evaluation routine
ctx - [optional] user-defined context for private data for the Jacobian evaluation routine (may be PETSC_NULL)

Calling sequence of func

    func (SNES snes,Vec x,Mat *A,Mat *B,int *flag,void *ctx);

x - input vector
A - Jacobian matrix
B - preconditioner matrix, usually the same as A
flag - flag indicating information about the preconditioner matrix structure (same as flag in SLESSetOperators())
ctx - [optional] user-defined Jacobian context

Notes

See SLESSetOperators() for important information about setting the flag output parameter in the routine func(). Be sure to read this information!

The routine func() takes Mat * as the matrix arguments rather than Mat. This allows the Jacobian evaluation routine to replace A and/or B with a completely new new matrix structure (not just different matrix elements) when appropriate, for instance, if the nonzero structure is changing throughout the global iterations.

Keywords

SNES, nonlinear, set, Jacobian, matrix

See Also

SLESSetOperators(), SNESSetFunction()

Level:beginner
Location:
src/snes/interface/snes.c
Index of all SNES routines
Table of Contents for all manual pages
Index of all manual pages

Examples

src/snes/examples/tutorials/ex1.c.html
src/snes/examples/tutorials/ex2.c.html
src/snes/examples/tutorials/ex3.c.html
src/snes/examples/tutorials/ex5.c.html
src/snes/examples/tutorials/ex5s.c.html
src/snes/examples/tutorials/ex6.c.html
src/snes/examples/tutorials/ex14.c.html
src/snes/examples/tutorials/ex24.c.html
src/snes/examples/tutorials/ex26.c.html
src/snes/examples/tutorials/ex1f.F.html
src/snes/examples/tutorials/ex5f.F.html