1: #pragma once

  3: #include <petsc/private/snesimpl.h>

  5: /*  Data structure for the Nonlinear GMRES method.  */
  6: typedef struct {
  7:   /* Solver parameters and counters */
  8:   PetscInt    msize;            /* maximum size of krylov space */
  9:   PetscInt    restart_it;       /* number of iterations the restart conditions persist before restart */
 10:   PetscViewer monitor;          /* debugging output for NGMRES */
 11:   PetscInt    restart_periodic; /* number of iterations to restart after */

 13:   SNESNGMRESRestartType restart_type;
 14:   SNESNGMRESSelectType  select_type;

 16:   /* History and subspace data */
 17:   Vec       *Fdot;   /* residual history -- length msize */
 18:   Vec       *Xdot;   /* solution history -- length msize */
 19:   PetscReal *fnorms; /* the residual norm history  */
 20:   PetscReal *xnorms; /* the solution norm history */

 22:   /* General minimization problem context */
 23:   PetscScalar *h;    /* the constraint matrix */
 24:   PetscScalar *beta; /* rhs for the minimization problem */
 25:   PetscScalar *xi;   /* the dot-product of the current and previous res. */

 27:   /* Line searches */
 28:   SNESLineSearch additive_linesearch; /* Line search for the additive variant */
 29:   PetscReal      descent_ls_test;     /* restart GMRES when X_A -X_M is not a descent direction */

 31:   /* Selection constants */
 32:   PetscBool candidate;       /* use candidate storage approach */
 33:   PetscBool approxfunc;      /* approximate the function rather than recomputing it */
 34:   PetscReal gammaA;          /* Criterion A residual tolerance */
 35:   PetscReal epsilonB;        /* Criterion B difference tolerance */
 36:   PetscReal deltaB;          /* Criterion B residual tolerance */
 37:   PetscReal gammaC;          /* Restart residual tolerance */
 38:   PetscBool restart_fm_rise; /* Restart on F_M residual increase */

 40:   PetscReal andersonBeta; /* Relaxation parameter for Anderson Mixing */

 42:   // Window of stored iterates that the least-squares problem uses
 43:   PetscInt  window_size;         /* maximum number of stored iterates in the window, at most msize */
 44:   PetscInt  window_size_initial; /* initial window size of the adaptive strategy */
 45:   PetscBool adaptive;            /* grow the window when theta predicts the residual reduction */
 46:   PetscReal adaptive_tol;        /* tolerance on |theta - ||F_{k+1}|| / ||F_k||| that grows the window */
 47:   PetscReal lsnorm;              /* least-squares objective, the norm of the minimized combination of residuals */
 48:   PetscReal theta;               /* least-squares objective divided by the residual norm ||F_k|| of the current iterate */
 49:   PetscReal gamma;               /* least-squares objective divided by the residual norm of the candidate solution */
 50:   PetscInt *window;              /* history indices of the iterates in the window, in increasing order */
 51:   Vec      *Fwindow;             /* array of references to the residuals in the window, not new Vec objects */
 52:   Vec      *Xwindow;             /* array of references to the solutions in the window, not new Vec objects */

 54:   /* Least squares minimization solve context */
 55:   PetscScalar *q;     /* the matrix formed as q_ij = (rdot_i, rdot_j) */
 56:   PetscBLASInt m;     /* matrix dimension */
 57:   PetscBLASInt n;     /* matrix dimension */
 58:   PetscBLASInt nrhs;  /* the number of right-hand sides */
 59:   PetscBLASInt lda;   /* the padded matrix dimension */
 60:   PetscBLASInt ldb;   /* the padded vector dimension */
 61:   PetscReal   *s;     /* the singular values */
 62:   PetscReal    rcond; /* the exit condition */
 63:   PetscBLASInt rank;  /* the effective rank */
 64:   PetscScalar *work;  /* the work vector */
 65:   PetscReal   *rwork; /* the real work vector used for complex */
 66:   PetscBLASInt lwork; /* the size of the work vector */

 68:   PetscBool setup_called; /* indicates whether SNESSetUp_NGMRES() has been called  */
 69: } SNES_NGMRES;

 71: #define H(i, j) ngmres->h[(i) * ngmres->msize + (j)]
 72: #define Q(i, j) ngmres->q[(i) * ngmres->msize + (j)]

 74: /* private functions that are shared components of the methods */
 75: PETSC_INTERN PetscErrorCode SNESNGMRESUpdateSubspace_Private(SNES, PetscInt, PetscInt, Vec, PetscReal, Vec);
 76: PETSC_INTERN PetscErrorCode SNESNGMRESFormCombinedSolution_Private(SNES, PetscInt, PetscInt, Vec, Vec, PetscReal, Vec, Vec, Vec);
 77: PETSC_INTERN PetscErrorCode SNESNGMRESNorms_Private(SNES, PetscInt, Vec, Vec, Vec, Vec, Vec, Vec, Vec, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *, PetscReal *);
 78: PETSC_INTERN PetscErrorCode SNESNGMRESSelect_Private(SNES, PetscInt, Vec, Vec, PetscReal, PetscReal, PetscReal, PetscReal, Vec, Vec, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal, Vec, Vec, Vec, PetscReal *, PetscReal *, PetscReal *);
 79: PETSC_INTERN PetscErrorCode SNESNGMRESSelectRestart_Private(SNES, PetscInt, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal, PetscBool *);

 81: PETSC_INTERN PetscErrorCode SNESNGMRESGetAdditiveLineSearch_Private(SNES, SNESLineSearch *);
 82: PETSC_INTERN PetscErrorCode SNESDestroy_NGMRES(SNES);
 83: PETSC_INTERN PetscErrorCode SNESReset_NGMRES(SNES);
 84: PETSC_INTERN PetscErrorCode SNESSetUp_NGMRES(SNES);
 85: PETSC_INTERN PetscErrorCode SNESView_NGMRES(SNES, PetscViewer);