SNESNewtonALSetFunction#

Sets a user function that is called at each function evaluation to compute the tangent load vector for the arc-length continuation method.

Synopsis#

#include "petscsnes.h" 
PetscErrorCode SNESNewtonALSetFunction(SNES snes, SNESFunctionFn *func, void *ctx)

Logically Collective

Input Parameters#

snes - the nonlinear solver object
func - [optional] tangent load function evaluation routine, see SNESFunctionFn for the calling sequence. U is the current solution vector, Q is the output tangent load vector
ctx - [optional] user-defined context for private data for the function evaluation routine (may be NULL)

Notes#

If the current value of the load parameter is needed in func, it can be obtained with SNESNewtonALGetLoadParameter().

The tangent load vector is the partial derivative of external load with respect to the load parameter. In the case of proportional loading, the tangent load vector is the full external load vector at the end of the load step.