/*
   Context for a Newton trust region method for solving a system
   of nonlinear equations
 */

#if !defined(__SNES_TR_H)
#define __SNES_TR_H
#include <petsc/private/snesimpl.h>

typedef struct {
  /* ---- Parameters used by the trust region method  ---- */
  PetscReal      mu;             /* used to compute trust region parameter */
  PetscReal      eta;            /* used to compute trust region parameter */
  PetscReal      delta;          /* trust region parameter */
  PetscReal      delta0;         /* used to initialize trust region parameter */
  PetscReal      delta1;         /* used to compute trust region parameter */
  PetscReal      delta2;         /* used to compute trust region parameter */
  PetscReal      delta3;         /* used to compute trust region parameter */
  PetscReal      sigma;          /* used to detemine termination */
  PetscBool      itflag;         /* flag for convergence testing */
  PetscReal      rnorm0,ttol;    /* used for KSP convergence test */
  PetscErrorCode (*precheck)(SNES,Vec,Vec,PetscBool*,void*);
  void           *precheckctx;
  PetscErrorCode (*postcheck)(SNES,Vec,Vec,Vec,PetscBool*,PetscBool*,void*);
  void           *postcheckctx;
} SNES_NEWTONTR;

#endif