1 #include <petsc/private/tsimpl.h> /*I "petscts.h" I*/ 2 3 typedef struct { 4 PetscBool always_accept; 5 PetscReal clip[2]; /* admissible decrease/increase factors */ 6 PetscReal safety; /* safety factor relative to target error */ 7 PetscReal reject_safety; /* extra safety factor if the last step was rejected */ 8 Vec X; 9 Vec Y; 10 Vec E; 11 } TSAdapt_GLEE; 12 13 static PetscErrorCode TSAdaptChoose_GLEE(TSAdapt adapt,TS ts,PetscReal h,PetscInt *next_sc,PetscReal *next_h,PetscBool *accept,PetscReal *wlte,PetscReal *wltea,PetscReal *wlter) 14 { 15 TSAdapt_GLEE *glee = (TSAdapt_GLEE*)adapt->data; 16 TSType time_scheme; /* Type of time-integration scheme */ 17 PetscErrorCode ierr; 18 Vec X,Y,E; 19 PetscReal enorm,enorma,enormr,hfac_lte,hfac_ltea,hfac_lter,h_lte,safety; 20 PetscInt order,stepno; 21 PetscBool bGTEMethod=PETSC_FALSE; 22 23 PetscFunctionBegin; 24 25 *next_sc = 0; /* Reuse the same order scheme */ 26 safety = glee->safety; 27 ierr = TSGetTimeStepNumber(ts,&stepno);CHKERRQ(ierr); 28 ierr = TSGetType(ts,&time_scheme);CHKERRQ(ierr); 29 if (!strcmp(time_scheme,TSGLEE)) bGTEMethod=PETSC_TRUE; 30 order = adapt->candidates.order[0]; 31 32 if (bGTEMethod){/* the method is of GLEE type */ 33 ierr = TSGetSolution(ts,&X);CHKERRQ(ierr); 34 if (!glee->E) {ierr = VecDuplicate(X,&glee->E);CHKERRQ(ierr);} 35 E = glee->E; 36 ierr = TSGetTimeError(ts,0,&E);CHKERRQ(ierr); 37 /* this should be called with Y (the solution at the beginning of the step)*/ 38 ierr = TSErrorWeightedENorm(ts,E,X,X,adapt->wnormtype,&enorm,&enorma,&enormr);CHKERRQ(ierr); 39 } else { 40 /* the method is NOT of GLEE type; use the stantard basic augmented by separate atol and rtol */ 41 ierr = TSGetSolution(ts,&X);CHKERRQ(ierr); 42 if (!glee->Y) {ierr = VecDuplicate(X,&glee->Y);CHKERRQ(ierr);} 43 Y = glee->Y; 44 ierr = TSEvaluateStep(ts,order-1,Y,NULL);CHKERRQ(ierr); 45 ierr = TSErrorWeightedNorm(ts,X,Y,adapt->wnormtype,&enorm,&enorma,&enormr);CHKERRQ(ierr); 46 } 47 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 PetscFunctionReturn(0); 55 } 56 57 if (enorm > 1. || enorma > 1. || enormr > 1.) { 58 if (!*accept) safety *= glee->reject_safety; /* The last attempt also failed, shorten more aggressively */ 59 if (h < (1 + PETSC_SQRT_MACHINE_EPSILON)*adapt->dt_min) { 60 ierr = 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);CHKERRQ(ierr); 61 *accept = PETSC_TRUE; 62 } else if (glee->always_accept) { 63 ierr = 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);CHKERRQ(ierr); 64 *accept = PETSC_TRUE; 65 } else { 66 ierr = 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);CHKERRQ(ierr); 67 *accept = PETSC_FALSE; 68 } 69 } else { 70 ierr = 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);CHKERRQ(ierr); 71 *accept = PETSC_TRUE; 72 } 73 74 if (bGTEMethod){ 75 /* The optimal new step based on the current global truncation error. */ 76 if (enorm > 0) { 77 /* factor based on the absolute tolerance */ 78 hfac_ltea = safety * PetscPowReal(1./enorma,((PetscReal)1)/order); 79 /* factor based on the relative tolerance */ 80 hfac_lter = safety * PetscPowReal(1./enormr,((PetscReal)1)/order); 81 /* pick the minimum time step among the relative and absolute tolerances */ 82 hfac_lte = PetscMin(hfac_ltea,hfac_lter); 83 } else { 84 hfac_lte = safety * PETSC_INFINITY; 85 } 86 h_lte = h * PetscClipInterval(hfac_lte,glee->clip[0],glee->clip[1]); 87 *next_h = PetscClipInterval(h_lte,adapt->dt_min,adapt->dt_max); 88 } else { 89 /* The optimal new step based purely on local truncation error for this step. */ 90 if (enorm > 0) { 91 /* factor based on the absolute tolerance */ 92 hfac_ltea = safety * PetscPowReal(enorma,((PetscReal)-1)/order); 93 /* factor based on the relative tolerance */ 94 hfac_lter = safety * PetscPowReal(enormr,((PetscReal)-1)/order); 95 /* pick the minimum time step among the relative and absolute tolerances */ 96 hfac_lte = PetscMin(hfac_ltea,hfac_lter); 97 } else { 98 hfac_lte = safety * PETSC_INFINITY; 99 } 100 h_lte = h * PetscClipInterval(hfac_lte,glee->clip[0],glee->clip[1]); 101 *next_h = PetscClipInterval(h_lte,adapt->dt_min,adapt->dt_max); 102 } 103 *wlte = enorm; 104 *wltea = enorma; 105 *wlter = enormr; 106 PetscFunctionReturn(0); 107 } 108 109 static PetscErrorCode TSAdaptReset_GLEE(TSAdapt adapt) 110 { 111 TSAdapt_GLEE *glee = (TSAdapt_GLEE*)adapt->data; 112 PetscErrorCode ierr; 113 114 PetscFunctionBegin; 115 ierr = VecDestroy(&glee->Y);CHKERRQ(ierr); 116 PetscFunctionReturn(0); 117 } 118 119 static PetscErrorCode TSAdaptDestroy_GLEE(TSAdapt adapt) 120 { 121 PetscErrorCode ierr; 122 123 PetscFunctionBegin; 124 ierr = TSAdaptReset_GLEE(adapt);CHKERRQ(ierr); 125 ierr = PetscFree(adapt->data);CHKERRQ(ierr); 126 PetscFunctionReturn(0); 127 } 128 129 static PetscErrorCode TSAdaptSetFromOptions_GLEE(PetscOptionItems *PetscOptionsObject,TSAdapt adapt) 130 { 131 TSAdapt_GLEE *glee = (TSAdapt_GLEE*)adapt->data; 132 PetscErrorCode ierr; 133 PetscInt two; 134 PetscBool set; 135 136 PetscFunctionBegin; 137 ierr = PetscOptionsHead(PetscOptionsObject,"GLEE adaptive controller options");CHKERRQ(ierr); 138 two = 2; 139 ierr = PetscOptionsRealArray("-ts_adapt_glee_clip","Admissible decrease/increase in step size","",glee->clip,&two,&set);CHKERRQ(ierr); 140 if (set && (two != 2 || glee->clip[0] > glee->clip[1])) SETERRQ(PetscObjectComm((PetscObject)adapt),PETSC_ERR_ARG_OUTOFRANGE,"Must give exactly two values to -ts_adapt_glee_clip"); 141 ierr = PetscOptionsReal("-ts_adapt_glee_safety","Safety factor relative to target error","",glee->safety,&glee->safety,NULL);CHKERRQ(ierr); 142 ierr = PetscOptionsReal("-ts_adapt_glee_reject_safety","Extra safety factor to apply if the last step was rejected","",glee->reject_safety,&glee->reject_safety,NULL);CHKERRQ(ierr); 143 ierr = PetscOptionsBool("-ts_adapt_glee_always_accept","Always accept the step regardless of whether local truncation error meets goal","",glee->always_accept,&glee->always_accept,NULL);CHKERRQ(ierr); 144 ierr = PetscOptionsTail();CHKERRQ(ierr); 145 PetscFunctionReturn(0); 146 } 147 148 static PetscErrorCode TSAdaptView_GLEE(TSAdapt adapt,PetscViewer viewer) 149 { 150 TSAdapt_GLEE *glee = (TSAdapt_GLEE*)adapt->data; 151 PetscErrorCode ierr; 152 PetscBool iascii; 153 154 PetscFunctionBegin; 155 ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr); 156 if (iascii) { 157 if (glee->always_accept) {ierr = PetscViewerASCIIPrintf(viewer," GLEE: always accepting steps\n");CHKERRQ(ierr);} 158 ierr = PetscViewerASCIIPrintf(viewer," GLEE: clip fastest decrease %g, fastest increase %g\n",(double)glee->clip[0],(double)glee->clip[1]);CHKERRQ(ierr); 159 ierr = PetscViewerASCIIPrintf(viewer," GLEE: safety factor %g, extra factor after step rejection %g\n",(double)glee->safety,(double)glee->reject_safety);CHKERRQ(ierr); 160 } 161 PetscFunctionReturn(0); 162 } 163 164 /*MC 165 TSADAPTGLEE - GLEE adaptive controller for time stepping 166 167 Level: intermediate 168 169 .seealso: TS, TSAdapt, TSSetAdapt() 170 M*/ 171 PETSC_EXTERN PetscErrorCode TSAdaptCreate_GLEE(TSAdapt adapt) 172 { 173 PetscErrorCode ierr; 174 TSAdapt_GLEE *a; 175 176 PetscFunctionBegin; 177 ierr = PetscNewLog(adapt,&a);CHKERRQ(ierr); 178 adapt->data = (void*)a; 179 adapt->ops->choose = TSAdaptChoose_GLEE; 180 adapt->ops->setfromoptions = TSAdaptSetFromOptions_GLEE; 181 adapt->ops->destroy = TSAdaptDestroy_GLEE; 182 adapt->ops->view = TSAdaptView_GLEE; 183 184 a->clip[0] = 0.1; 185 a->clip[1] = 10.; 186 a->safety = 0.9; 187 a->reject_safety = 0.5; 188 a->always_accept = PETSC_FALSE; 189 PetscFunctionReturn(0); 190 } 191