1: #pragma once
  2: typedef struct _RKTableau *RKTableau;
  3: struct _RKTableau {
  4:   char      *name;
  5:   PetscInt   order;     /* Classical approximation order of the method i              */
  6:   PetscInt   s;         /* Number of stages                                           */
  7:   PetscInt   p;         /* Interpolation order                                        */
  8:   PetscBool  FSAL;      /* flag to indicate if tableau is FSAL                        */
  9:   PetscReal *A, *b, *c; /* Tableau                                                    */
 10:   PetscReal *bembed;    /* Embedded formula of order one less (order-1)               */
 11:   PetscReal *binterp;   /* Dense output formula                                       */
 12:   PetscReal  ccfl;      /* Placeholder for CFL coefficient relative to forward Euler  */
 13: };
 14: typedef struct _RKTableauLink *RKTableauLink;
 15: struct _RKTableauLink {
 16:   struct _RKTableau tab;
 17:   RKTableauLink     next;
 18: };

 20: typedef struct {
 21:   RKTableau    tableau;
 22:   PetscBool    newtableau; /* flag to indicate if tableau has changed */
 23:   Vec          X0;
 24:   Vec         *Y;            /* States computed during the step                                              */
 25:   Vec         *YdotRHS;      /* Function evaluations for the non-stiff part and contains all components      */
 26:   Vec         *YdotRHS_fast; /* Function evaluations for the non-stiff part and contains fast components     */
 27:   Vec         *YdotRHS_slow; /* Function evaluations for the non-stiff part and contains slow components     */
 28:   Vec         *VecsDeltaLam; /* Increment of the adjoint sensitivity w.r.t IC at stage                       */
 29:   Vec         *VecsSensiTemp;
 30:   Vec          VecDeltaMu;    /* Increment of the adjoint sensitivity w.r.t P at stage                        */
 31:   Vec         *VecsDeltaLam2; /* Increment of the 2nd-order adjoint sensitivity w.r.t IC at stage */
 32:   Vec          VecDeltaMu2;   /* Increment of the 2nd-order adjoint sensitivity w.r.t P at stage */
 33:   Vec         *VecsSensi2Temp;
 34:   PetscScalar *work; /* Scalar work                                                                  */
 35:   PetscInt     slow; /* flag indicates call slow components solver (0) or fast components solver (1) */
 36:   PetscReal    stage_time;
 37:   TSStepStatus status;
 38:   PetscReal    ptime;
 39:   PetscReal    time_step;
 40:   PetscInt     dtratio; /* ratio between slow time step size and fast step size                         */
 41:   IS           is_fast, is_slow;
 42:   TS           subts_fast, subts_slow, subts_current, ts_root;
 43:   PetscBool    use_multirate;
 44:   Mat          MatFwdSensip0;
 45:   Mat         *MatsFwdStageSensip;
 46:   Mat         *MatsFwdSensipTemp;
 47:   Vec          VecDeltaFwdSensipCol; /* Working vector for holding one column of the sensitivity matrix */
 48: } TS_RK;