/*
   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      eta1;           /* Heeho's new TR-dogleg */
  PetscReal      eta2;           /* Heeho's new TR-dogleg */
  PetscReal      eta3;           /* Heeho's new TR-dogleg */
  PetscReal      t1;             /* Heeho's new TR-dogleg */
  PetscReal      t2;             /* Heeho's new TR-dogleg */
  PetscReal      deltaM;         /* Heeho's new TR-dogleg */
  /* currently using fixed array for the block size because of memory leak */
  /* PetscReal      *inorms;         Heeho's new TR-dogleg, stores largest inf norm */
  /* PetscInt       bs;              Heeho's new TR-dogleg, solution vector block size */

  PetscReal      sigma;          /* used to detemine termination */
  PetscBool      itflag;         /* flag for convergence testing */
  PetscBool      use_cauchy;     /* flag to use/not use Cauchy step and direction (S&D) */
  PetscBool      auto_scale_multiphase; /* flag to use/not use autoscaling for Cauchy S&D for multiphase*/
  PetscReal      auto_scale_max; /* max cap value for auto-scaling muste be > 1 */
  PetscBool      rho_satisfied;  /* flag for whether inner iteration satisfied rho */
  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_NEWTONTRDC;

#endif