Actual source code: adaptglee.c
petsc-3.13.6 2020-09-29
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      1:  #include <petsc/private/tsimpl.h>

      3: typedef struct {
      4:   Vec E,Y;
      5: } TSAdapt_GLEE;

      7: static PetscErrorCode TSAdaptChoose_GLEE(TSAdapt adapt,TS ts,PetscReal h,PetscInt *next_sc,PetscReal *next_h,PetscBool *accept,PetscReal *wlte,PetscReal *wltea,PetscReal *wlter)
      8: {
      9:   TSAdapt_GLEE  *glee = (TSAdapt_GLEE*)adapt->data;
     10:   TSType         time_scheme;      /* Type of time-integration scheme        */
     12:   Vec            X,Y,E;
     13:   PetscReal      enorm,enorma,enormr,hfac_lte,hfac_ltea,hfac_lter,h_lte,safety;
     14:   PetscInt       order;
     15:   PetscBool      bGTEMethod=PETSC_FALSE;

     19:   *next_sc = 0; /* Reuse the same order scheme */
     20:   safety = adapt->safety;
     21:   TSGetType(ts,&time_scheme);
     22:   if (!strcmp(time_scheme,TSGLEE)) bGTEMethod=PETSC_TRUE;
     23:   order = adapt->candidates.order[0];

     25:   if (bGTEMethod){/* the method is of GLEE type */
     26:     TSGetSolution(ts,&X);
     27:     if (!glee->Y && adapt->glee_use_local) {
     28:       VecDuplicate(X,&glee->Y);/*create vector to store previous step global error*/
     29:       VecZeroEntries(glee->Y); /*set error to zero on the first step - may not work if error is not zero initially*/
     30:     }
     31:     if (!glee->E) {VecDuplicate(X,&glee->E);}
     32:     E    = glee->E;
     33:     TSGetTimeError(ts,0,&E);

     35:     if (adapt->glee_use_local) {VecAXPY(E,-1.0,glee->Y);} /* local error = current error - previous step error */

     37:     /* this should be called with the solution at the beginning of the step too*/
     38:     TSErrorWeightedENorm(ts,E,X,X,adapt->wnormtype,&enorm,&enorma,&enormr);
     39:   } else {
     40:     /* the method is NOT of GLEE type; use the stantard basic augmented by separate atol and rtol */
     41:     TSGetSolution(ts,&X);
     42:     if (!glee->Y) {VecDuplicate(X,&glee->Y);}
     43:     Y     = glee->Y;
     44:     TSEvaluateStep(ts,order-1,Y,NULL);
     45:     TSErrorWeightedNorm(ts,X,Y,adapt->wnormtype,&enorm,&enorma,&enormr);
     46:   }

     48:   if (enorm < 0) {
     49:     *accept  = PETSC_TRUE;
     50:     *next_h  = h;            /* Reuse the old step */
     51:     *wlte    = -1;           /* Weighted error was not evaluated */
     52:     *wltea   = -1;           /* Weighted absolute error was not evaluated */
     53:     *wlter   = -1;           /* Weighted relative error was not evaluated */
     54:     return(0);
     55:   }

     57:   if (enorm > 1. || enorma > 1. || enormr > 1.) {
     58:     if (!*accept) safety *= adapt->reject_safety; /* The last attempt also failed, shorten more aggressively */
     59:     if (h < (1 + PETSC_SQRT_MACHINE_EPSILON)*adapt->dt_min) {
     60:       PetscInfo4(adapt,"Estimated scaled truncation error [combined, absolute, relative]] [%g, %g, %g], accepting because step size %g is at minimum\n",(double)enorm,(double)enorma,(double)enormr,(double)h);
     61:       *accept = PETSC_TRUE;
     62:     } else if (adapt->always_accept) {
     63:       PetscInfo4(adapt,"Estimated scaled truncation error [combined, absolute, relative]] [%g, %g, %g], accepting step of size %g because always_accept is set\n",(double)enorm,(double)enorma,(double)enormr,(double)h);
     64:       *accept = PETSC_TRUE;
     65:     } else {
     66:       PetscInfo4(adapt,"Estimated scaled truncation error [combined, absolute, relative]] [%g, %g, %g], rejecting step of size %g\n",(double)enorm,(double)enorma,(double)enormr,(double)h);
     67:       *accept = PETSC_FALSE;
     68:     }
     69:   } else {
     70:     PetscInfo4(adapt,"Estimated scaled truncation error [combined, absolute, relative] [%g, %g, %g], accepting step of size %g\n",(double)enorm,(double)enorma,(double)enormr,(double)h);
     71:     *accept = PETSC_TRUE;
     72:   }

     74:   if (bGTEMethod){
     75:     if (*accept == PETSC_TRUE && adapt->glee_use_local) {
     76:       /* If step is accepted, then overwrite previous step error with the current error to be used on the next step */
     77:       /* WARNING: if the adapters are composable, then the accept test will not be reliable*/
     78:       TSGetTimeError(ts,0,&(glee->Y));
     79:     }

     81:     /* The optimal new step based on the current global truncation error. */
     82:     if (enorm > 0) {
     83:       /* factor based on the absolute tolerance */
     84:       hfac_ltea = safety * PetscPowReal(1./enorma,((PetscReal)1)/(order+1));
     85:       /* factor based on the relative tolerance */
     86:       hfac_lter = safety * PetscPowReal(1./enormr,((PetscReal)1)/(order+1));
     87:       /* pick the minimum time step among the relative and absolute tolerances */
     88:       hfac_lte  = PetscMin(hfac_ltea,hfac_lter);
     89:     } else {
     90:       hfac_lte = safety * PETSC_INFINITY;
     91:     }
     92:     h_lte = h * PetscClipInterval(hfac_lte,adapt->clip[0],adapt->clip[1]);
     93:     *next_h = PetscClipInterval(h_lte,adapt->dt_min,adapt->dt_max);
     94:   } else {
     95:     /* The optimal new step based purely on local truncation error for this step. */
     96:     if (enorm > 0) {
     97:       /* factor based on the absolute tolerance */
     98:       hfac_ltea = safety * PetscPowReal(enorma,((PetscReal)-1)/order);
     99:       /* factor based on the relative tolerance */
    100:       hfac_lter = safety * PetscPowReal(enormr,((PetscReal)-1)/order);
    101:       /* pick the minimum time step among the relative and absolute tolerances */
    102:       hfac_lte  = PetscMin(hfac_ltea,hfac_lter);
    103:     } else {
    104:       hfac_lte = safety * PETSC_INFINITY;
    105:     }
    106:     h_lte = h * PetscClipInterval(hfac_lte,adapt->clip[0],adapt->clip[1]);
    107:     *next_h = PetscClipInterval(h_lte,adapt->dt_min,adapt->dt_max);
    108:   }
    109:   *wlte   = enorm;
    110:   *wltea  = enorma;
    111:   *wlter  = enormr;
    112:   return(0);
    113: }

    115: static PetscErrorCode TSAdaptReset_GLEE(TSAdapt adapt)
    116: {
    117:   TSAdapt_GLEE  *glee = (TSAdapt_GLEE*)adapt->data;

    121:   VecDestroy(&glee->Y);
    122:   VecDestroy(&glee->E);
    123:   return(0);
    124: }

    126: static PetscErrorCode TSAdaptDestroy_GLEE(TSAdapt adapt)
    127: {

    131:   TSAdaptReset_GLEE(adapt);
    132:   PetscFree(adapt->data);
    133:   return(0);
    134: }

    136: /*MC
    137:    TSADAPTGLEE - GLEE adaptive controller for time stepping

    139:    Level: intermediate

    141: .seealso: TS, TSAdapt, TSGetAdapt()
    142: M*/
    143: PETSC_EXTERN PetscErrorCode TSAdaptCreate_GLEE(TSAdapt adapt)
    144: {
    146:   TSAdapt_GLEE  *glee;

    149:   PetscNewLog(adapt,&glee);
    150:   adapt->data         = (void*)glee;
    151:   adapt->ops->choose  = TSAdaptChoose_GLEE;
    152:   adapt->ops->reset   = TSAdaptReset_GLEE;
    153:   adapt->ops->destroy = TSAdaptDestroy_GLEE;
    154:   return(0);
    155: }