Date: 2021-03-03T22:28:03+00:00

Actual source code: ex5.c
petsc-3.14.5 2021-03-03
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      1: /*
      2:   Note:
      3:   To performance a convergence study, a reference solution can be generated with a small stepsize and stored into a binary file, e.g. -ts_type ssp -ts_dt 1e-5 -ts_max_steps 30000 -ts_view_solution binary:reference.bin
      4:   Errors can be computed in the following runs with -simulation -f reference.bin

      6:   Multirate RK options:
      7:   -ts_rk_dtratio is the ratio between larger time step size and small time step size
      8:   -ts_rk_multirate_type has three choices: none (for single step RK)
      9:                                            combined (for multirate method and user just need to provide the same RHS with the single step RK)
     10:                                            partitioned (for multiraet method and user need to provide two RHS, one is for fast components and the orther is for slow components
     11: */

     13: static const char help[] = "1D periodic Finite Volume solver in slope-limiter form with semidiscrete time stepping.\n"
     14:   " advection   - Variable coefficient scalar advection\n"
     15:   "                u_t       + (a*u)_x               = 0\n"
     16:   " a is a piecewise function with two values say a0 and a1 (both a0 and a1 are constant).\n"
     17:   " in this toy problem we assume a=a0 when x<0 and a=a1 when x>0 with a0<a1 which has the same discontinuous point with initial condition.\n"
     18:   " we don't provide an exact solution, so you need to generate reference solution to do convergnece staudy,\n"
     19:   " more precisely, you need firstly generate a reference to a binary file say file.bin, then on commend line,\n"
     20:   " you should type -simulation -f file.bin.\n"
     21:   " you can choose the number of grids by -da_grid_x.\n"
     22:   " you can choose the value of a by -physics_advect_a1 and -physics_advect_a2.\n";

     24: #include <petscts.h>
     25: #include <petscdm.h>
     26: #include <petscdmda.h>
     27: #include <petscdraw.h>
     28: #include <petsc/private/tsimpl.h>

     30: #include <petsc/private/kernels/blockinvert.h>

     32: #include "finitevolume1d.h"

     34: PETSC_STATIC_INLINE PetscReal RangeMod(PetscReal a,PetscReal xmin,PetscReal xmax) { PetscReal range = xmax-xmin; return xmin +PetscFmodReal(range+PetscFmodReal(a,range),range); }

     36: /* --------------------------------- Advection ----------------------------------- */

     38: typedef struct {
     39:   PetscReal a[2];                  /* advective velocity */
     40: } AdvectCtx;

     42: static PetscErrorCode PhysicsRiemann_Advect(void *vctx,PetscInt m,const PetscScalar *uL,const PetscScalar *uR,PetscScalar *flux,PetscReal *maxspeed,PetscReal x,PetscReal xmin, PetscReal xmax)
     43: {
     44:   AdvectCtx *ctx = (AdvectCtx*)vctx;
     45:   PetscReal *speed;

     48:   speed = ctx->a;
     49:   if (x==0 || x == xmin || x == xmax) flux[0] = PetscMax(0,(speed[0]+speed[1])/2.0)*uL[0] + PetscMin(0,(speed[0]+speed[1])/2.0)*uR[0]; /* if condition need to be changed base on different problem, '0' is the discontinuous point of a */
     50:   else if (x<0) flux[0] = PetscMax(0,speed[0])*uL[0] + PetscMin(0,speed[0])*uR[0];  /* else if condition need to be changed based on diferent problem, 'x = 0' is discontinuous point of a */
     51:   else flux[0] = PetscMax(0,speed[1])*uL[0] + PetscMin(0,speed[1])*uR[0];
     52:   *maxspeed = *speed;
     53:   return(0);
     54: }

     56: static PetscErrorCode PhysicsCharacteristic_Advect(void *vctx,PetscInt m,const PetscScalar *u,PetscScalar *X,PetscScalar *Xi,PetscReal *speeds,PetscReal x)
     57: {
     58:   AdvectCtx *ctx = (AdvectCtx*)vctx;

     61:   X[0]      = 1.;
     62:   Xi[0]     = 1.;
     63:   if (x<0) speeds[0] = ctx->a[0];  /* x is discontinuous point of a */
     64:   else    speeds[0] = ctx->a[1];
     65:   return(0);
     66: }

     68: static PetscErrorCode PhysicsSample_Advect(void *vctx,PetscInt initial,FVBCType bctype,PetscReal xmin,PetscReal xmax,PetscReal t,PetscReal x,PetscReal *u)
     69: {
     70:   AdvectCtx *ctx = (AdvectCtx*)vctx;
     71:   PetscReal *a    = ctx->a,x0;

     74:   if (x<0){   /* x is cell center */
     75:     switch (bctype) {
     76:       case FVBC_OUTFLOW:  x0 = x-a[0]*t; break;
     77:       case FVBC_PERIODIC: x0 = RangeMod(x-a[0]*t,xmin,xmax); break;
     78:       default: SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"unknown BCType");
     79:     }
     80:     switch (initial) {
     81:       case 0: u[0] = (x0 < 0) ? 1 : -1; break;
     82:       case 1: u[0] = (x0 < 0) ? -1 : 1; break;
     83:       case 2: u[0] = (0 < x0 && x0 < 1) ? 1 : 0; break;
     84:       case 3: u[0] = PetscSinReal(2*PETSC_PI*x0); break;
     85:       case 4: u[0] = PetscAbs(x0); break;
     86:       case 5: u[0] = (x0 < 0 || x0 > 0.5) ? 0 : PetscSqr(PetscSinReal(2*PETSC_PI*x0)); break;
     87:       case 6: u[0] = (x0 < 0) ? 0 : ((x0 < 1) ? x0 : ((x0 < 2) ? 2-x0 : 0)); break;
     88:       case 7: u[0] = PetscPowReal(PetscSinReal(PETSC_PI*x0),10.0);break;
     89:       default: SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"unknown initial condition");
     90:     }
     91:   }
     92:   else{
     93:     switch (bctype) {
     94:       case FVBC_OUTFLOW:  x0 = x-a[1]*t; break;
     95:       case FVBC_PERIODIC: x0 = RangeMod(x-a[1]*t,xmin,xmax); break;
     96:       default: SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"unknown BCType");
     97:     }
     98:     switch (initial) {
     99:       case 0: u[0] = (x0 < 0) ? 1 : -1; break;
    100:       case 1: u[0] = (x0 < 0) ? -1 : 1; break;
    101:       case 2: u[0] = (0 < x0 && x0 < 1) ? 1 : 0; break;
    102:       case 3: u[0] = PetscSinReal(2*PETSC_PI*x0); break;
    103:       case 4: u[0] = PetscAbs(x0); break;
    104:       case 5: u[0] = (x0 < 0 || x0 > 0.5) ? 0 : PetscSqr(PetscSinReal(2*PETSC_PI*x0)); break;
    105:       case 6: u[0] = (x0 < 0) ? 0 : ((x0 < 1) ? x0 : ((x0 < 2) ? 2-x0 : 0)); break;
    106:       case 7: u[0] = PetscPowReal(PetscSinReal(PETSC_PI*x0),10.0);break;
    107:       default: SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"unknown initial condition");
    108:     }
    109:   }
    110:   return(0);
    111: }

    113: static PetscErrorCode PhysicsCreate_Advect(FVCtx *ctx)
    114: {
    116:   AdvectCtx      *user;

    119:   PetscNew(&user);
    120:   ctx->physics.sample         = PhysicsSample_Advect;
    121:   ctx->physics.riemann        = PhysicsRiemann_Advect;
    122:   ctx->physics.characteristic = PhysicsCharacteristic_Advect;
    123:   ctx->physics.destroy        = PhysicsDestroy_SimpleFree;
    124:   ctx->physics.user           = user;
    125:   ctx->physics.dof            = 1;
    126:   PetscStrallocpy("u",&ctx->physics.fieldname[0]);
    127:   user->a[0] = 1;
    128:   user->a[1] = 1;
    129:   PetscOptionsBegin(ctx->comm,ctx->prefix,"Options for advection","");
    130:   {
    131:     PetscOptionsReal("-physics_advect_a1","Speed1","",user->a[0],&user->a[0],NULL);
    132:     PetscOptionsReal("-physics_advect_a2","Speed2","",user->a[1],&user->a[1],NULL);
    133:   }
    134:   PetscOptionsEnd();
    135:   return(0);
    136: }

    138: /* --------------------------------- Finite Volume Solver for slow parts ----------------------------------- */

    140: PetscErrorCode FVRHSFunctionslow(TS ts,PetscReal time,Vec X,Vec F,void *vctx)
    141: {
    142:   FVCtx          *ctx = (FVCtx*)vctx;
    144:   PetscInt       i,j,k,Mx,dof,xs,xm,len_slow;
    145:   PetscReal      hx,cfl_idt = 0;
    146:   PetscScalar    *x,*f,*slope;
    147:   Vec            Xloc;
    148:   DM             da;

    151:   TSGetDM(ts,&da);
    152:   DMGetLocalVector(da,&Xloc);
    153:   DMDAGetInfo(da,0, &Mx,0,0, 0,0,0, &dof,0,0,0,0,0);
    154:   hx   = (ctx->xmax-ctx->xmin)/Mx;
    155:   DMGlobalToLocalBegin(da,X,INSERT_VALUES,Xloc);
    156:   DMGlobalToLocalEnd(da,X,INSERT_VALUES,Xloc);
    157:   VecZeroEntries(F);
    158:   DMDAVecGetArray(da,Xloc,&x);
    159:   VecGetArray(F,&f);
    160:   DMDAGetArray(da,PETSC_TRUE,&slope);
    161:   DMDAGetCorners(da,&xs,0,0,&xm,0,0);
    162:   ISGetSize(ctx->iss,&len_slow);

    164:   if (ctx->bctype == FVBC_OUTFLOW) {
    165:     for (i=xs-2; i<0; i++) {
    166:       for (j=0; j<dof; j++) x[i*dof+j] = x[j];
    167:     }
    168:     for (i=Mx; i<xs+xm+2; i++) {
    169:       for (j=0; j<dof; j++) x[i*dof+j] = x[(xs+xm-1)*dof+j];
    170:     }
    171:   }
    172:   for (i=xs-1; i<xs+xm+1; i++) {
    173:     struct _LimitInfo info;
    174:     PetscScalar       *cjmpL,*cjmpR;
    175:     if (i < len_slow+1) {
    176:       /* Determine the right eigenvectors R, where A = R \Lambda R^{-1} */
    177:       (*ctx->physics.characteristic)(ctx->physics.user,dof,&x[i*dof],ctx->R,ctx->Rinv,ctx->speeds,ctx->xmin+hx*i);
    178:       /* Evaluate jumps across interfaces (i-1, i) and (i, i+1), put in characteristic basis */
    179:       PetscArrayzero(ctx->cjmpLR,2*dof);
    180:       cjmpL = &ctx->cjmpLR[0];
    181:       cjmpR = &ctx->cjmpLR[dof];
    182:       for (j=0; j<dof; j++) {
    183:         PetscScalar jmpL,jmpR;
    184:         jmpL = x[(i+0)*dof+j]-x[(i-1)*dof+j];
    185:         jmpR = x[(i+1)*dof+j]-x[(i+0)*dof+j];
    186:         for (k=0; k<dof; k++) {
    187:           cjmpL[k] += ctx->Rinv[k+j*dof]*jmpL;
    188:           cjmpR[k] += ctx->Rinv[k+j*dof]*jmpR;
    189:         }
    190:       }
    191:       /* Apply limiter to the left and right characteristic jumps */
    192:       info.m  = dof;
    193:       info.hx = hx;
    194:       (*ctx->limit)(&info,cjmpL,cjmpR,ctx->cslope);
    195:       for (j=0; j<dof; j++) ctx->cslope[j] /= hx; /* rescale to a slope */
    196:       for (j=0; j<dof; j++) {
    197:         PetscScalar tmp = 0;
    198:         for (k=0; k<dof; k++) tmp += ctx->R[j+k*dof]*ctx->cslope[k];
    199:         slope[i*dof+j] = tmp;
    200:       }
    201:     }
    202:   }

    204:   for (i=xs; i<xs+xm+1; i++) {
    205:     PetscReal   maxspeed;
    206:     PetscScalar *uL,*uR;
    207:     if (i < len_slow) { /* slow parts can be changed based on a */
    208:       uL = &ctx->uLR[0];
    209:       uR = &ctx->uLR[dof];
    210:       for (j=0; j<dof; j++) {
    211:         uL[j] = x[(i-1)*dof+j]+slope[(i-1)*dof+j]*hx/2;
    212:         uR[j] = x[(i-0)*dof+j]-slope[(i-0)*dof+j]*hx/2;
    213:       }
    214:       (*ctx->physics.riemann)(ctx->physics.user,dof,uL,uR,ctx->flux,&maxspeed,ctx->xmin+hx*i,ctx->xmin,ctx->xmax);
    215:       cfl_idt = PetscMax(cfl_idt,PetscAbsScalar(maxspeed/hx)); /* Max allowable value of 1/Delta t */
    216:       if (i > xs) {
    217:         for (j=0; j<dof; j++) f[(i-1)*dof+j] -= ctx->flux[j]/hx;
    218:       }
    219:       if (i < xs+xm) {
    220:         for (j=0; j<dof; j++) f[i*dof+j] += ctx->flux[j]/hx;
    221:       }
    222:     }
    223:     if (i == len_slow) { /* slow parts can be changed based on a */
    224:       uL = &ctx->uLR[0];
    225:       uR = &ctx->uLR[dof];
    226:       for (j=0; j<dof; j++) {
    227:         uL[j] = x[(i-1)*dof+j]+slope[(i-1)*dof+j]*hx/2;
    228:         uR[j] = x[(i-0)*dof+j]-slope[(i-0)*dof+j]*hx/2;
    229:       }
    230:       (*ctx->physics.riemann)(ctx->physics.user,dof,uL,uR,ctx->flux,&maxspeed,ctx->xmin+hx*i,ctx->xmin,ctx->xmax);
    231:       cfl_idt = PetscMax(cfl_idt,PetscAbsScalar(maxspeed/hx)); /* Max allowable value of 1/Delta t */
    232:       if (i > xs) {
    233:         for (j=0; j<dof; j++) f[(i-1)*dof+j] -= ctx->flux[j]/hx;
    234:       }
    235:     }
    236:   }
    237:   DMDAVecRestoreArray(da,Xloc,&x);
    238:   VecRestoreArray(F,&f);
    239:   DMDARestoreArray(da,PETSC_TRUE,&slope);
    240:   DMRestoreLocalVector(da,&Xloc);
    241:   return(0);
    242: }

    244: /* --------------------------------- Finite Volume Solver for fast  parts ----------------------------------- */

    246: PetscErrorCode FVRHSFunctionfast(TS ts,PetscReal time,Vec X,Vec F,void *vctx)
    247: {
    248:   FVCtx          *ctx = (FVCtx*)vctx;
    250:   PetscInt       i,j,k,Mx,dof,xs,xm,len_slow;
    251:   PetscReal      hx,cfl_idt = 0;
    252:   PetscScalar    *x,*f,*slope;
    253:   Vec            Xloc;
    254:   DM             da;

    257:   TSGetDM(ts,&da);
    258:   DMGetLocalVector(da,&Xloc);
    259:   DMDAGetInfo(da,0, &Mx,0,0, 0,0,0, &dof,0,0,0,0,0);
    260:   hx   = (ctx->xmax-ctx->xmin)/Mx;
    261:   DMGlobalToLocalBegin(da,X,INSERT_VALUES,Xloc);
    262:   DMGlobalToLocalEnd(da,X,INSERT_VALUES,Xloc);
    263:   VecZeroEntries(F);
    264:   DMDAVecGetArray(da,Xloc,&x);
    265:   VecGetArray(F,&f);
    266:   DMDAGetArray(da,PETSC_TRUE,&slope);
    267:   DMDAGetCorners(da,&xs,0,0,&xm,0,0);
    268:   ISGetSize(ctx->iss,&len_slow);

    270:   if (ctx->bctype == FVBC_OUTFLOW) {
    271:     for (i=xs-2; i<0; i++) {
    272:       for (j=0; j<dof; j++) x[i*dof+j] = x[j];
    273:     }
    274:     for (i=Mx; i<xs+xm+2; i++) {
    275:       for (j=0; j<dof; j++) x[i*dof+j] = x[(xs+xm-1)*dof+j];
    276:     }
    277:   }
    278:   for (i=xs-1; i<xs+xm+1; i++) {
    279:     struct _LimitInfo info;
    280:     PetscScalar       *cjmpL,*cjmpR;
    281:     if (i > len_slow-2) {
    282:       (*ctx->physics.characteristic)(ctx->physics.user,dof,&x[i*dof],ctx->R,ctx->Rinv,ctx->speeds,ctx->xmin+hx*i);
    283:       PetscArrayzero(ctx->cjmpLR,2*dof);
    284:       cjmpL = &ctx->cjmpLR[0];
    285:       cjmpR = &ctx->cjmpLR[dof];
    286:       for (j=0; j<dof; j++) {
    287:         PetscScalar jmpL,jmpR;
    288:         jmpL = x[(i+0)*dof+j]-x[(i-1)*dof+j];
    289:         jmpR = x[(i+1)*dof+j]-x[(i+0)*dof+j];
    290:         for (k=0; k<dof; k++) {
    291:           cjmpL[k] += ctx->Rinv[k+j*dof]*jmpL;
    292:           cjmpR[k] += ctx->Rinv[k+j*dof]*jmpR;
    293:         }
    294:       }
    295:       /* Apply limiter to the left and right characteristic jumps */
    296:       info.m  = dof;
    297:       info.hx = hx;
    298:       (*ctx->limit)(&info,cjmpL,cjmpR,ctx->cslope);
    299:       for (j=0; j<dof; j++) ctx->cslope[j] /= hx; /* rescale to a slope */
    300:       for (j=0; j<dof; j++) {
    301:         PetscScalar tmp = 0;
    302:         for (k=0; k<dof; k++) tmp += ctx->R[j+k*dof]*ctx->cslope[k];
    303:         slope[i*dof+j] = tmp;
    304:       }
    305:     }
    306:   }

    308:   for (i=xs; i<xs+xm+1; i++) {
    309:     PetscReal   maxspeed;
    310:     PetscScalar *uL,*uR;
    311:     if (i > len_slow) {
    312:       uL = &ctx->uLR[0];
    313:       uR = &ctx->uLR[dof];
    314:       for (j=0; j<dof; j++) {
    315:         uL[j] = x[(i-1)*dof+j]+slope[(i-1)*dof+j]*hx/2;
    316:         uR[j] = x[(i-0)*dof+j]-slope[(i-0)*dof+j]*hx/2;
    317:       }
    318:       (*ctx->physics.riemann)(ctx->physics.user,dof,uL,uR,ctx->flux,&maxspeed,ctx->xmin+hx*i,ctx->xmin,ctx->xmax);
    319:       cfl_idt = PetscMax(cfl_idt,PetscAbsScalar(maxspeed/hx)); /* Max allowable value of 1/Delta t */
    320:       if (i > xs) {
    321:         for (j=0; j<dof; j++) f[(i-len_slow-1)*dof+j] -= ctx->flux[j]/hx;
    322:       }
    323:       if (i < xs+xm) {
    324:         for (j=0; j<dof; j++) f[(i-len_slow)*dof+j] += ctx->flux[j]/hx;
    325:       }
    326:     }
    327:     if (i == len_slow) {
    328:       uL = &ctx->uLR[0];
    329:       uR = &ctx->uLR[dof];
    330:       for (j=0; j<dof; j++) {
    331:         uL[j] = x[(i-1)*dof+j]+slope[(i-1)*dof+j]*hx/2;
    332:         uR[j] = x[(i-0)*dof+j]-slope[(i-0)*dof+j]*hx/2;
    333:       }
    334:       (*ctx->physics.riemann)(ctx->physics.user,dof,uL,uR,ctx->flux,&maxspeed,ctx->xmin+hx*i,ctx->xmin,ctx->xmax);
    335:       cfl_idt = PetscMax(cfl_idt,PetscAbsScalar(maxspeed/hx)); /* Max allowable value of 1/Delta t */
    336:       if (i < xs+xm) {
    337:         for (j=0; j<dof; j++) f[(i-len_slow)*dof+j] += ctx->flux[j]/hx;
    338:       }
    339:     }
    340:   }
    341:   DMDAVecRestoreArray(da,Xloc,&x);
    342:   VecRestoreArray(F,&f);
    343:   DMDARestoreArray(da,PETSC_TRUE,&slope);
    344:   DMRestoreLocalVector(da,&Xloc);
    345:   return(0);
    346: }

    348: PetscErrorCode FVRHSFunctionslow2(TS ts,PetscReal time,Vec X,Vec F,void *vctx)
    349: {
    350:   FVCtx          *ctx = (FVCtx*)vctx;
    352:   PetscInt       i,j,k,Mx,dof,xs,xm,len_slow1,len_slow2;
    353:   PetscReal      hx,cfl_idt = 0;
    354:   PetscScalar    *x,*f,*slope;
    355:   Vec            Xloc;
    356:   DM             da;

    359:   TSGetDM(ts,&da);
    360:   DMGetLocalVector(da,&Xloc);
    361:   DMDAGetInfo(da,0, &Mx,0,0, 0,0,0, &dof,0,0,0,0,0);
    362:   hx   = (ctx->xmax-ctx->xmin)/Mx;
    363:   DMGlobalToLocalBegin(da,X,INSERT_VALUES,Xloc);
    364:   DMGlobalToLocalEnd(da,X,INSERT_VALUES,Xloc);
    365:   VecZeroEntries(F);
    366:   DMDAVecGetArray(da,Xloc,&x);
    367:   VecGetArray(F,&f);
    368:   DMDAGetArray(da,PETSC_TRUE,&slope);
    369:   DMDAGetCorners(da,&xs,0,0,&xm,0,0);
    370:   ISGetSize(ctx->iss,&len_slow1);
    371:   ISGetSize(ctx->iss2,&len_slow2);
    372:   if (ctx->bctype == FVBC_OUTFLOW) {
    373:     for (i=xs-2; i<0; i++) {
    374:       for (j=0; j<dof; j++) x[i*dof+j] = x[j];
    375:     }
    376:     for (i=Mx; i<xs+xm+2; i++) {
    377:       for (j=0; j<dof; j++) x[i*dof+j] = x[(xs+xm-1)*dof+j];
    378:     }
    379:   }
    380:   for (i=xs-1; i<xs+xm+1; i++) {
    381:     struct _LimitInfo info;
    382:     PetscScalar       *cjmpL,*cjmpR;
    383:     if (i < len_slow1+len_slow2+1 && i > len_slow1-2) {
    384:       (*ctx->physics.characteristic)(ctx->physics.user,dof,&x[i*dof],ctx->R,ctx->Rinv,ctx->speeds,ctx->xmin+hx*i);
    385:       PetscArrayzero(ctx->cjmpLR,2*dof);
    386:       cjmpL = &ctx->cjmpLR[0];
    387:       cjmpR = &ctx->cjmpLR[dof];
    388:       for (j=0; j<dof; j++) {
    389:         PetscScalar jmpL,jmpR;
    390:         jmpL = x[(i+0)*dof+j]-x[(i-1)*dof+j];
    391:         jmpR = x[(i+1)*dof+j]-x[(i+0)*dof+j];
    392:         for (k=0; k<dof; k++) {
    393:           cjmpL[k] += ctx->Rinv[k+j*dof]*jmpL;
    394:           cjmpR[k] += ctx->Rinv[k+j*dof]*jmpR;
    395:         }
    396:       }
    397:       /* Apply limiter to the left and right characteristic jumps */
    398:       info.m  = dof;
    399:       info.hx = hx;
    400:       (*ctx->limit)(&info,cjmpL,cjmpR,ctx->cslope);
    401:       for (j=0; j<dof; j++) ctx->cslope[j] /= hx; /* rescale to a slope */
    402:       for (j=0; j<dof; j++) {
    403:         PetscScalar tmp = 0;
    404:         for (k=0; k<dof; k++) tmp += ctx->R[j+k*dof]*ctx->cslope[k];
    405:         slope[i*dof+j] = tmp;
    406:       }
    407:     }
    408:   }

    410:   for (i=xs; i<xs+xm+1; i++) {
    411:     PetscReal   maxspeed;
    412:     PetscScalar *uL,*uR;
    413:     if (i < len_slow1+len_slow2 && i > len_slow1) { /* slow parts can be changed based on a */
    414:       uL = &ctx->uLR[0];
    415:       uR = &ctx->uLR[dof];
    416:       for (j=0; j<dof; j++) {
    417:         uL[j] = x[(i-1)*dof+j]+slope[(i-1)*dof+j]*hx/2;
    418:         uR[j] = x[(i-0)*dof+j]-slope[(i-0)*dof+j]*hx/2;
    419:       }
    420:       (*ctx->physics.riemann)(ctx->physics.user,dof,uL,uR,ctx->flux,&maxspeed,ctx->xmin+hx*i,ctx->xmin,ctx->xmax);
    421:       cfl_idt = PetscMax(cfl_idt,PetscAbsScalar(maxspeed/hx)); /* Max allowable value of 1/Delta t */
    422:       if (i > xs) {
    423:         for (j=0; j<dof; j++) f[(i-len_slow1-1)*dof+j] -= ctx->flux[j]/hx;
    424:       }
    425:       if (i < xs+xm) {
    426:         for (j=0; j<dof; j++) f[(i-len_slow1)*dof+j] += ctx->flux[j]/hx;
    427:       }
    428:     }
    429:     if (i == len_slow1+len_slow2) { /* slow parts can be changed based on a */
    430:       uL = &ctx->uLR[0];
    431:       uR = &ctx->uLR[dof];
    432:       for (j=0; j<dof; j++) {
    433:         uL[j] = x[(i-1)*dof+j]+slope[(i-1)*dof+j]*hx/2;
    434:         uR[j] = x[(i-0)*dof+j]-slope[(i-0)*dof+j]*hx/2;
    435:       }
    436:       (*ctx->physics.riemann)(ctx->physics.user,dof,uL,uR,ctx->flux,&maxspeed,ctx->xmin+hx*i,ctx->xmin,ctx->xmax);
    437:       cfl_idt = PetscMax(cfl_idt,PetscAbsScalar(maxspeed/hx)); /* Max allowable value of 1/Delta t */
    438:       if (i > xs) {
    439:         for (j=0; j<dof; j++) f[(i-len_slow1-1)*dof+j] -= ctx->flux[j]/hx;
    440:       }
    441:     }
    442:     if (i == len_slow1) { /* slow parts can be changed based on a */
    443:       uL = &ctx->uLR[0];
    444:       uR = &ctx->uLR[dof];
    445:       for (j=0; j<dof; j++) {
    446:         uL[j] = x[(i-1)*dof+j]+slope[(i-1)*dof+j]*hx/2;
    447:         uR[j] = x[(i-0)*dof+j]-slope[(i-0)*dof+j]*hx/2;
    448:       }
    449:       (*ctx->physics.riemann)(ctx->physics.user,dof,uL,uR,ctx->flux,&maxspeed,ctx->xmin+hx*i,ctx->xmin,ctx->xmax);
    450:       cfl_idt = PetscMax(cfl_idt,PetscAbsScalar(maxspeed/hx)); /* Max allowable value of 1/Delta t */
    451:       if (i < xs+xm) {
    452:         for (j=0; j<dof; j++) f[(i-len_slow1)*dof+j] += ctx->flux[j]/hx;
    453:       }
    454:     }
    455:   }

    457:   DMDAVecRestoreArray(da,Xloc,&x);
    458:   VecRestoreArray(F,&f);
    459:   DMDARestoreArray(da,PETSC_TRUE,&slope);
    460:   DMRestoreLocalVector(da,&Xloc);
    461:   return(0);
    462: }

    464: PetscErrorCode FVRHSFunctionfast2(TS ts,PetscReal time,Vec X,Vec F,void *vctx)
    465: {
    466:   FVCtx          *ctx = (FVCtx*)vctx;
    468:   PetscInt       i,j,k,Mx,dof,xs,xm,len_slow1,len_slow2;
    469:   PetscReal      hx,cfl_idt = 0;
    470:   PetscScalar    *x,*f,*slope;
    471:   Vec            Xloc;
    472:   DM             da;

    475:   TSGetDM(ts,&da);
    476:   DMGetLocalVector(da,&Xloc);
    477:   DMDAGetInfo(da,0, &Mx,0,0, 0,0,0, &dof,0,0,0,0,0);
    478:   hx   = (ctx->xmax-ctx->xmin)/Mx;
    479:   DMGlobalToLocalBegin(da,X,INSERT_VALUES,Xloc);
    480:   DMGlobalToLocalEnd(da,X,INSERT_VALUES,Xloc);
    481:   VecZeroEntries(F);
    482:   DMDAVecGetArray(da,Xloc,&x);
    483:   VecGetArray(F,&f);
    484:   DMDAGetArray(da,PETSC_TRUE,&slope);
    485:   DMDAGetCorners(da,&xs,0,0,&xm,0,0);
    486:   ISGetSize(ctx->iss,&len_slow1);
    487:   ISGetSize(ctx->iss2,&len_slow2);

    489:   if (ctx->bctype == FVBC_OUTFLOW) {
    490:     for (i=xs-2; i<0; i++) {
    491:       for (j=0; j<dof; j++) x[i*dof+j] = x[j];
    492:     }
    493:     for (i=Mx; i<xs+xm+2; i++) {
    494:       for (j=0; j<dof; j++) x[i*dof+j] = x[(xs+xm-1)*dof+j];
    495:     }
    496:   }
    497:   for (i=xs-1; i<xs+xm+1; i++) {
    498:     struct _LimitInfo info;
    499:     PetscScalar       *cjmpL,*cjmpR;
    500:     if (i > len_slow1+len_slow2-2) {
    501:       (*ctx->physics.characteristic)(ctx->physics.user,dof,&x[i*dof],ctx->R,ctx->Rinv,ctx->speeds,ctx->xmin+hx*i);
    502:       PetscArrayzero(ctx->cjmpLR,2*dof);
    503:       cjmpL = &ctx->cjmpLR[0];
    504:       cjmpR = &ctx->cjmpLR[dof];
    505:       for (j=0; j<dof; j++) {
    506:         PetscScalar jmpL,jmpR;
    507:         jmpL = x[(i+0)*dof+j]-x[(i-1)*dof+j];
    508:         jmpR = x[(i+1)*dof+j]-x[(i+0)*dof+j];
    509:         for (k=0; k<dof; k++) {
    510:           cjmpL[k] += ctx->Rinv[k+j*dof]*jmpL;
    511:           cjmpR[k] += ctx->Rinv[k+j*dof]*jmpR;
    512:         }
    513:       }
    514:       /* Apply limiter to the left and right characteristic jumps */
    515:       info.m  = dof;
    516:       info.hx = hx;
    517:       (*ctx->limit)(&info,cjmpL,cjmpR,ctx->cslope);
    518:       for (j=0; j<dof; j++) ctx->cslope[j] /= hx; /* rescale to a slope */
    519:       for (j=0; j<dof; j++) {
    520:         PetscScalar tmp = 0;
    521:         for (k=0; k<dof; k++) tmp += ctx->R[j+k*dof]*ctx->cslope[k];
    522:         slope[i*dof+j] = tmp;
    523:       }
    524:     }
    525:   }

    527:   for (i=xs; i<xs+xm+1; i++) {
    528:     PetscReal   maxspeed;
    529:     PetscScalar *uL,*uR;
    530:     if (i > len_slow1+len_slow2) {
    531:       uL = &ctx->uLR[0];
    532:       uR = &ctx->uLR[dof];
    533:       for (j=0; j<dof; j++) {
    534:         uL[j] = x[(i-1)*dof+j]+slope[(i-1)*dof+j]*hx/2;
    535:         uR[j] = x[(i-0)*dof+j]-slope[(i-0)*dof+j]*hx/2;
    536:       }
    537:       (*ctx->physics.riemann)(ctx->physics.user,dof,uL,uR,ctx->flux,&maxspeed,ctx->xmin+hx*i,ctx->xmin,ctx->xmax);
    538:       cfl_idt = PetscMax(cfl_idt,PetscAbsScalar(maxspeed/hx)); /* Max allowable value of 1/Delta t */
    539:       if (i > xs) {
    540:         for (j=0; j<dof; j++) f[(i-len_slow1-len_slow2-1)*dof+j] -= ctx->flux[j]/hx;
    541:       }
    542:       if (i < xs+xm) {
    543:         for (j=0; j<dof; j++) f[(i-len_slow1-len_slow2)*dof+j] += ctx->flux[j]/hx;
    544:       }
    545:     }
    546:     if (i == len_slow1+len_slow2) {
    547:       uL = &ctx->uLR[0];
    548:       uR = &ctx->uLR[dof];
    549:       for (j=0; j<dof; j++) {
    550:         uL[j] = x[(i-1)*dof+j]+slope[(i-1)*dof+j]*hx/2;
    551:         uR[j] = x[(i-0)*dof+j]-slope[(i-0)*dof+j]*hx/2;
    552:       }
    553:       (*ctx->physics.riemann)(ctx->physics.user,dof,uL,uR,ctx->flux,&maxspeed,ctx->xmin+hx*i,ctx->xmin,ctx->xmax);
    554:       cfl_idt = PetscMax(cfl_idt,PetscAbsScalar(maxspeed/hx)); /* Max allowable value of 1/Delta t */
    555:       if (i < xs+xm) {
    556:         for (j=0; j<dof; j++) f[(i-len_slow1-len_slow2)*dof+j] += ctx->flux[j]/hx;
    557:       }
    558:     }
    559:   }
    560:   DMDAVecRestoreArray(da,Xloc,&x);
    561:   VecRestoreArray(F,&f);
    562:   DMDARestoreArray(da,PETSC_TRUE,&slope);
    563:   DMRestoreLocalVector(da,&Xloc);
    564:   return(0);
    565: }

    567: int main(int argc,char *argv[])
    568: {
    569:   char              lname[256] = "mc",physname[256] = "advect",final_fname[256] = "solution.m";
    570:   PetscFunctionList limiters   = 0,physics = 0;
    571:   MPI_Comm          comm;
    572:   TS                ts;
    573:   DM                da;
    574:   Vec               X,X0,R;
    575:   FVCtx             ctx;
    576:   PetscInt          i,k,dof,xs,xm,Mx,draw = 0,*index_slow,*index_fast,islow = 0,ifast = 0;
    577:   PetscBool         view_final = PETSC_FALSE;
    578:   PetscReal         ptime;
    579:   PetscErrorCode    ierr;

    581:   PetscInitialize(&argc,&argv,0,help);if (ierr) return ierr;
    582:   comm = PETSC_COMM_WORLD;
    583:   PetscMemzero(&ctx,sizeof(ctx));

    585:   /* Register limiters to be available on the command line */
    586:   PetscFunctionListAdd(&limiters,"upwind"              ,Limit_Upwind);
    587:   PetscFunctionListAdd(&limiters,"lax-wendroff"        ,Limit_LaxWendroff);
    588:   PetscFunctionListAdd(&limiters,"beam-warming"        ,Limit_BeamWarming);
    589:   PetscFunctionListAdd(&limiters,"fromm"               ,Limit_Fromm);
    590:   PetscFunctionListAdd(&limiters,"minmod"              ,Limit_Minmod);
    591:   PetscFunctionListAdd(&limiters,"superbee"            ,Limit_Superbee);
    592:   PetscFunctionListAdd(&limiters,"mc"                  ,Limit_MC);
    593:   PetscFunctionListAdd(&limiters,"vanleer"             ,Limit_VanLeer);
    594:   PetscFunctionListAdd(&limiters,"vanalbada"           ,Limit_VanAlbada);
    595:   PetscFunctionListAdd(&limiters,"vanalbadatvd"        ,Limit_VanAlbadaTVD);
    596:   PetscFunctionListAdd(&limiters,"koren"               ,Limit_Koren);
    597:   PetscFunctionListAdd(&limiters,"korensym"            ,Limit_KorenSym);
    598:   PetscFunctionListAdd(&limiters,"koren3"              ,Limit_Koren3);
    599:   PetscFunctionListAdd(&limiters,"cada-torrilhon2"     ,Limit_CadaTorrilhon2);
    600:   PetscFunctionListAdd(&limiters,"cada-torrilhon3-r0p1",Limit_CadaTorrilhon3R0p1);
    601:   PetscFunctionListAdd(&limiters,"cada-torrilhon3-r1"  ,Limit_CadaTorrilhon3R1);
    602:   PetscFunctionListAdd(&limiters,"cada-torrilhon3-r10" ,Limit_CadaTorrilhon3R10);
    603:   PetscFunctionListAdd(&limiters,"cada-torrilhon3-r100",Limit_CadaTorrilhon3R100);

    605:   /* Register physical models to be available on the command line */
    606:   PetscFunctionListAdd(&physics,"advect"          ,PhysicsCreate_Advect);

    608:   ctx.comm = comm;
    609:   ctx.cfl  = 0.9;
    610:   ctx.bctype = FVBC_PERIODIC;
    611:   ctx.xmin = -1.0;
    612:   ctx.xmax = 1.0;
    613:   PetscOptionsBegin(comm,NULL,"Finite Volume solver options","");
    614:   PetscOptionsReal("-xmin","X min","",ctx.xmin,&ctx.xmin,NULL);
    615:   PetscOptionsReal("-xmax","X max","",ctx.xmax,&ctx.xmax,NULL);
    616:   PetscOptionsFList("-limit","Name of flux limiter to use","",limiters,lname,lname,sizeof(lname),NULL);
    617:   PetscOptionsInt("-draw","Draw solution vector, bitwise OR of (1=initial,2=final,4=final error)","",draw,&draw,NULL);
    618:   PetscOptionsString("-view_final","Write final solution in ASCII MATLAB format to given file name","",final_fname,final_fname,sizeof(final_fname),&view_final);
    619:   PetscOptionsInt("-initial","Initial condition (depends on the physics)","",ctx.initial,&ctx.initial,NULL);
    620:   PetscOptionsBool("-simulation","Compare errors with reference solution","",ctx.simulation,&ctx.simulation,NULL);
    621:   PetscOptionsReal("-cfl","CFL number to time step at","",ctx.cfl,&ctx.cfl,NULL);
    622:   PetscOptionsEnum("-bc_type","Boundary condition","",FVBCTypes,(PetscEnum)ctx.bctype,(PetscEnum*)&ctx.bctype,NULL);
    623:   PetscOptionsBool("-recursive_split","Split the domain recursively","",ctx.recursive,&ctx.recursive,NULL);
    624:   PetscOptionsEnd();

    626:   /* Choose the limiter from the list of registered limiters */
    627:   PetscFunctionListFind(limiters,lname,&ctx.limit);
    628:   if (!ctx.limit) SETERRQ1(PETSC_COMM_SELF,1,"Limiter '%s' not found",lname);

    630:   /* Choose the physics from the list of registered models */
    631:   {
    632:     PetscErrorCode (*r)(FVCtx*);
    633:     PetscFunctionListFind(physics,physname,&r);
    634:     if (!r) SETERRQ1(PETSC_COMM_SELF,1,"Physics '%s' not found",physname);
    635:     /* Create the physics, will set the number of fields and their names */
    636:     (*r)(&ctx);
    637:   }

    639:   /* Create a DMDA to manage the parallel grid */
    640:   DMDACreate1d(comm,DM_BOUNDARY_PERIODIC,50,ctx.physics.dof,2,NULL,&da);
    641:   DMSetFromOptions(da);
    642:   DMSetUp(da);
    643:   /* Inform the DMDA of the field names provided by the physics. */
    644:   /* The names will be shown in the title bars when run with -ts_monitor_draw_solution */
    645:   for (i=0; i<ctx.physics.dof; i++) {
    646:     DMDASetFieldName(da,i,ctx.physics.fieldname[i]);
    647:   }
    648:   DMDAGetInfo(da,0, &Mx,0,0, 0,0,0, &dof,0,0,0,0,0);
    649:   DMDAGetCorners(da,&xs,0,0,&xm,0,0);

    651:   /* Set coordinates of cell centers */
    652:   DMDASetUniformCoordinates(da,ctx.xmin+0.5*(ctx.xmax-ctx.xmin)/Mx,ctx.xmax+0.5*(ctx.xmax-ctx.xmin)/Mx,0,0,0,0);

    654:   /* Allocate work space for the Finite Volume solver (so it doesn't have to be reallocated on each function evaluation) */
    655:   PetscMalloc4(dof*dof,&ctx.R,dof*dof,&ctx.Rinv,2*dof,&ctx.cjmpLR,1*dof,&ctx.cslope);
    656:   PetscMalloc3(2*dof,&ctx.uLR,dof,&ctx.flux,dof,&ctx.speeds);

    658:   /* Create a vector to store the solution and to save the initial state */
    659:   DMCreateGlobalVector(da,&X);
    660:   VecDuplicate(X,&X0);
    661:   VecDuplicate(X,&R);

    663:   /*-------------------------------- create index for slow parts and fast parts ----------------------------------------*/
    664:   PetscMalloc1(xm*dof,&index_slow);
    665:   PetscMalloc1(xm*dof,&index_fast);
    666:   for (i=xs; i<xs+xm; i++) {
    667:     if (ctx.xmin+i*(ctx.xmax-ctx.xmin)/(PetscReal)Mx+0.5*(ctx.xmax-ctx.xmin)/(PetscReal)Mx < 0)
    668:       for (k=0; k<dof; k++) index_slow[islow++] = i*dof+k;
    669:     else
    670:       for (k=0; k<dof; k++) index_fast[ifast++] = i*dof+k;
    671:   }  /* this step need to be changed based on discontinuous point of a */
    672:   ISCreateGeneral(PETSC_COMM_WORLD,islow,index_slow,PETSC_COPY_VALUES,&ctx.iss);
    673:   ISCreateGeneral(PETSC_COMM_WORLD,ifast,index_fast,PETSC_COPY_VALUES,&ctx.isf);

    675:   /* Create a time-stepping object */
    676:   TSCreate(comm,&ts);
    677:   TSSetDM(ts,da);
    678:   TSSetRHSFunction(ts,R,FVRHSFunction,&ctx);
    679:   TSRHSSplitSetIS(ts,"slow",ctx.iss);
    680:   TSRHSSplitSetIS(ts,"fast",ctx.isf);
    681:   TSRHSSplitSetRHSFunction(ts,"slow",NULL,FVRHSFunctionslow,&ctx);
    682:   TSRHSSplitSetRHSFunction(ts,"fast",NULL,FVRHSFunctionfast,&ctx);

    684:   if (ctx.recursive) {
    685:     TS subts;
    686:     islow = 0;
    687:     ifast = 0;
    688:     for (i=xs; i<xs+xm; i++) {
    689:       PetscReal coord = ctx.xmin+i*(ctx.xmax-ctx.xmin)/(PetscReal)Mx+0.5*(ctx.xmax-ctx.xmin)/(PetscReal)Mx;
    690:       if (coord >= 0 && coord < ctx.xmin+(ctx.xmax-ctx.xmin)*3/4.)
    691:         for (k=0; k<dof; k++) index_slow[islow++] = i*dof+k;
    692:       if (coord >= ctx.xmin+(ctx.xmax-ctx.xmin)*3/4.)
    693:         for (k=0; k<dof; k++) index_fast[ifast++] = i*dof+k;
    694:     }  /* this step need to be changed based on discontinuous point of a */
    695:     ISCreateGeneral(PETSC_COMM_WORLD,islow,index_slow,PETSC_COPY_VALUES,&ctx.iss2);
    696:     ISCreateGeneral(PETSC_COMM_WORLD,ifast,index_fast,PETSC_COPY_VALUES,&ctx.isf2);

    698:     TSRHSSplitGetSubTS(ts,"fast",&subts);
    699:     TSRHSSplitSetIS(subts,"slow",ctx.iss2);
    700:     TSRHSSplitSetIS(subts,"fast",ctx.isf2);
    701:     TSRHSSplitSetRHSFunction(subts,"slow",NULL,FVRHSFunctionslow2,&ctx);
    702:     TSRHSSplitSetRHSFunction(subts,"fast",NULL,FVRHSFunctionfast2,&ctx);
    703:   }

    705:   /*TSSetType(ts,TSSSP);*/
    706:   TSSetType(ts,TSMPRK);
    707:   TSSetMaxTime(ts,10);
    708:   TSSetExactFinalTime(ts,TS_EXACTFINALTIME_STEPOVER);

    710:   /* Compute initial conditions and starting time step */
    711:   FVSample(&ctx,da,0,X0);
    712:   FVRHSFunction(ts,0,X0,X,(void*)&ctx); /* Initial function evaluation, only used to determine max speed */
    713:   VecCopy(X0,X);                        /* The function value was not used so we set X=X0 again */
    714:   TSSetTimeStep(ts,ctx.cfl/ctx.cfl_idt);
    715:   TSSetFromOptions(ts); /* Take runtime options */
    716:   SolutionStatsView(da,X,PETSC_VIEWER_STDOUT_WORLD);
    717:   {
    718:     PetscInt    steps;
    719:     PetscScalar mass_initial,mass_final,mass_difference;

    721:     TSSolve(ts,X);
    722:     TSGetSolveTime(ts,&ptime);
    723:     TSGetStepNumber(ts,&steps);
    724:     PetscPrintf(comm,"Final time %g, steps %D\n",(double)ptime,steps);
    725:     /* calculate the total mass at initial time and final time */
    726:     mass_initial = 0.0;
    727:     mass_final   = 0.0;
    728:     VecSum(X0,&mass_initial);
    729:     VecSum(X,&mass_final);
    730:     mass_difference = (ctx.xmax-ctx.xmin)/(PetscScalar)Mx*(mass_final - mass_initial);
    731:     PetscPrintf(comm,"Mass difference %g\n",(double)mass_difference);
    732:     if (ctx.simulation) {
    733:       PetscViewer  fd;
    734:       char         filename[PETSC_MAX_PATH_LEN] = "binaryoutput";
    735:       Vec          XR;
    736:       PetscReal    nrm1,nrmsup;
    737:       PetscBool    flg;
    738:       PetscOptionsGetString(NULL,NULL,"-f",filename,sizeof(filename),&flg);
    739:       if (!flg) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER,"Must indicate binary file with the -f option");
    740:       PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&fd);
    741:       VecDuplicate(X0,&XR);
    742:       VecLoad(XR,fd);
    743:       PetscViewerDestroy(&fd);
    744:       VecAYPX(XR,-1,X);
    745:       VecNorm(XR,NORM_1,&nrm1);
    746:       VecNorm(XR,NORM_INFINITY,&nrmsup);
    747:       nrm1 /= Mx;
    748:       PetscPrintf(comm,"Error ||x-x_e||_1 %g  ||x-x_e||_sup %g\n",(double)nrm1,(double)nrmsup);
    749:       VecDestroy(&XR);
    750:     }
    751:   }

    753:   SolutionStatsView(da,X,PETSC_VIEWER_STDOUT_WORLD);
    754:   if (draw & 0x1) {VecView(X0,PETSC_VIEWER_DRAW_WORLD);}
    755:   if (draw & 0x2) {VecView(X,PETSC_VIEWER_DRAW_WORLD);}
    756:   if (draw & 0x4) {
    757:     Vec Y;
    758:     VecDuplicate(X,&Y);
    759:     FVSample(&ctx,da,ptime,Y);
    760:     VecAYPX(Y,-1,X);
    761:     VecView(Y,PETSC_VIEWER_DRAW_WORLD);
    762:     VecDestroy(&Y);
    763:   }

    765:   if (view_final) {
    766:     PetscViewer viewer;
    767:     PetscViewerASCIIOpen(PETSC_COMM_WORLD,final_fname,&viewer);
    768:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
    769:     VecView(X,viewer);
    770:     PetscViewerPopFormat(viewer);
    771:     PetscViewerDestroy(&viewer);
    772:   }

    774:   /* Clean up */
    775:   (*ctx.physics.destroy)(ctx.physics.user);
    776:   for (i=0; i<ctx.physics.dof; i++) {PetscFree(ctx.physics.fieldname[i]);}
    777:   PetscFree4(ctx.R,ctx.Rinv,ctx.cjmpLR,ctx.cslope);
    778:   PetscFree3(ctx.uLR,ctx.flux,ctx.speeds);
    779:   ISDestroy(&ctx.iss);
    780:   ISDestroy(&ctx.isf);
    781:   ISDestroy(&ctx.iss2);
    782:   ISDestroy(&ctx.isf2);
    783:   VecDestroy(&X);
    784:   VecDestroy(&X0);
    785:   VecDestroy(&R);
    786:   DMDestroy(&da);
    787:   TSDestroy(&ts);
    788:   PetscFree(index_slow);
    789:   PetscFree(index_fast);
    790:   PetscFunctionListDestroy(&limiters);
    791:   PetscFunctionListDestroy(&physics);
    792:   PetscFinalize();
    793:   return ierr;
    794: }

    796: /*TEST
    797:     build:
    798:       requires: !complex
    799:       depends: finitevolume1d.c

    801:     test:
    802:       args: -da_grid_x 60 -initial 1 -xmin -1 -xmax 1 -limit mc -physics_advect_a1 1 -physics_advect_a2 2 -ts_dt 0.025 -ts_max_steps 24 -ts_type rk -ts_rk_type 2a -ts_rk_dtratio 2 -ts_rk_multirate -ts_use_splitrhsfunction 0

    804:     test:
    805:       suffix: 2
    806:       args: -da_grid_x 60 -initial 1 -xmin -1 -xmax 1 -limit mc -physics_advect_a1 1 -physics_advect_a2 2 -ts_dt 0.025 -ts_max_steps 24 -ts_type rk -ts_rk_type 2a -ts_rk_dtratio 2 -ts_rk_multirate -ts_use_splitrhsfunction 1
    807:       output_file: output/ex5_1.out

    809:     test:
    810:       suffix: 3
    811:       args: -da_grid_x 60 -initial 1 -xmin -1 -xmax 1 -limit mc -physics_advect_a1 1 -physics_advect_a2 2 -ts_dt 0.025 -ts_max_steps 24 -ts_type mprk -ts_mprk_type 2a22 -ts_use_splitrhsfunction 0

    813:     test:
    814:       suffix: 4
    815:       args: -da_grid_x 60 -initial 1 -xmin -1 -xmax 1 -limit mc -physics_advect_a1 1 -physics_advect_a2 2 -ts_dt 0.025 -ts_max_steps 24 -ts_type mprk -ts_mprk_type 2a22 -ts_use_splitrhsfunction 1
    816:       output_file: output/ex5_3.out

    818:     test:
    819:       suffix: 5
    820:       args: -da_grid_x 60 -initial 1 -xmin -1 -xmax 1 -limit mc -physics_advect_a1 1 -physics_advect_a2 2 -ts_dt 0.025 -ts_max_steps 24 -ts_type rk -ts_rk_type 2a -ts_rk_dtratio 2 -ts_rk_multirate -ts_use_splitrhsfunction 0 -recursive_split

    822:     test:
    823:       suffix: 6
    824:       args: -da_grid_x 60 -initial 1 -xmin -1 -xmax 1 -limit mc -physics_advect_a1 1 -physics_advect_a2 2 -ts_dt 0.025 -ts_max_steps 24 -ts_type rk -ts_rk_type 2a -ts_rk_dtratio 2 -ts_rk_multirate -ts_use_splitrhsfunction 1 -recursive_split
    825: TEST*/