Actual source code: ex8.c

  1: static const char help[] = "1D periodic Finite Volume solver in slope-limiter form with semidiscrete time stepping.\n"
  2:                            "  advection   - Constant coefficient scalar advection\n"
  3:                            "                u_t       + (a*u)_x               = 0\n"
  4:                            "  for this toy problem, we choose different meshsizes for different sub-domains (slow-medium-fast-medium-slow), \n"
  5:                            "  the meshsize ratio between two adjacient sub-domains is controlled with -hratio,\n"
  6:                            "  exact       - Exact Riemann solver which usually needs to perform a Newton iteration to connect\n"
  7:                            "                the states across shocks and rarefactions\n"
  8:                            "  simulation  - use reference solution which is generated by smaller time step size to be true solution,\n"
  9:                            "                also the reference solution should be generated by user and stored in a binary file.\n"
 10:                            "  characteristic - Limit the characteristic variables, this is usually preferred (default)\n"
 11:                            "Several initial conditions can be chosen with -initial N\n\n"
 12:                            "The problem size should be set with -da_grid_x M\n\n";

 14: #include <petscts.h>
 15: #include <petscdm.h>
 16: #include <petscdmda.h>
 17: #include "finitevolume1d.h"

 19: static inline PetscReal RangeMod(PetscReal a, PetscReal xmin, PetscReal xmax)
 20: {
 21:   PetscReal range = xmax - xmin;
 22:   return xmin + PetscFmodReal(range + PetscFmodReal(a, range), range);
 23: }

 25: /* --------------------------------- Advection ----------------------------------- */
 26: typedef struct {
 27:   PetscReal a; /* advective velocity */
 28: } AdvectCtx;

 30: static PetscErrorCode PhysicsRiemann_Advect(void *vctx, PetscInt m, const PetscScalar *uL, const PetscScalar *uR, PetscScalar *flux, PetscReal *maxspeed)
 31: {
 32:   AdvectCtx *ctx = (AdvectCtx *)vctx;
 33:   PetscReal  speed;

 35:   PetscFunctionBeginUser;
 36:   speed     = ctx->a;
 37:   flux[0]   = PetscMax(0, speed) * uL[0] + PetscMin(0, speed) * uR[0];
 38:   *maxspeed = speed;
 39:   PetscFunctionReturn(PETSC_SUCCESS);
 40: }

 42: static PetscErrorCode PhysicsCharacteristic_Advect(void *vctx, PetscInt m, const PetscScalar *u, PetscScalar *X, PetscScalar *Xi, PetscReal *speeds)
 43: {
 44:   AdvectCtx *ctx = (AdvectCtx *)vctx;

 46:   PetscFunctionBeginUser;
 47:   X[0]      = 1.;
 48:   Xi[0]     = 1.;
 49:   speeds[0] = ctx->a;
 50:   PetscFunctionReturn(PETSC_SUCCESS);
 51: }

 53: static PetscErrorCode PhysicsSample_Advect(void *vctx, PetscInt initial, FVBCType bctype, PetscReal xmin, PetscReal xmax, PetscReal t, PetscReal x, PetscReal *u)
 54: {
 55:   AdvectCtx *ctx = (AdvectCtx *)vctx;
 56:   PetscReal  a   = ctx->a, x0;

 58:   PetscFunctionBeginUser;
 59:   switch (bctype) {
 60:   case FVBC_OUTFLOW:
 61:     x0 = x - a * t;
 62:     break;
 63:   case FVBC_PERIODIC:
 64:     x0 = RangeMod(x - a * t, xmin, xmax);
 65:     break;
 66:   default:
 67:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_UNKNOWN_TYPE, "unknown BCType");
 68:   }
 69:   switch (initial) {
 70:   case 0:
 71:     u[0] = (x0 < 0) ? 1 : -1;
 72:     break;
 73:   case 1:
 74:     u[0] = (x0 < 0) ? -1 : 1;
 75:     break;
 76:   case 2:
 77:     u[0] = (0 < x0 && x0 < 1) ? 1 : 0;
 78:     break;
 79:   case 3:
 80:     u[0] = PetscSinReal(2 * PETSC_PI * x0);
 81:     break;
 82:   case 4:
 83:     u[0] = PetscAbs(x0);
 84:     break;
 85:   case 5:
 86:     u[0] = (x0 < 0 || x0 > 0.5) ? 0 : PetscSqr(PetscSinReal(2 * PETSC_PI * x0));
 87:     break;
 88:   case 6:
 89:     u[0] = (x0 < 0) ? 0 : ((x0 < 1) ? x0 : ((x0 < 2) ? 2 - x0 : 0));
 90:     break;
 91:   case 7:
 92:     u[0] = PetscPowReal(PetscSinReal(PETSC_PI * x0), 10.0);
 93:     break;
 94:   default:
 95:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_UNKNOWN_TYPE, "unknown initial condition");
 96:   }
 97:   PetscFunctionReturn(PETSC_SUCCESS);
 98: }

100: static PetscErrorCode PhysicsCreate_Advect(FVCtx *ctx)
101: {
102:   AdvectCtx *user;

104:   PetscFunctionBeginUser;
105:   PetscCall(PetscNew(&user));
106:   ctx->physics2.sample2         = PhysicsSample_Advect;
107:   ctx->physics2.riemann2        = PhysicsRiemann_Advect;
108:   ctx->physics2.characteristic2 = PhysicsCharacteristic_Advect;
109:   ctx->physics2.destroy         = PhysicsDestroy_SimpleFree;
110:   ctx->physics2.user            = user;
111:   ctx->physics2.dof             = 1;
112:   PetscCall(PetscStrallocpy("u", &ctx->physics2.fieldname[0]));
113:   user->a = 1;
114:   PetscOptionsBegin(ctx->comm, ctx->prefix, "Options for advection", "");
115:   {
116:     PetscCall(PetscOptionsReal("-physics_advect_a", "Speed", "", user->a, &user->a, NULL));
117:   }
118:   PetscOptionsEnd();
119:   PetscFunctionReturn(PETSC_SUCCESS);
120: }

122: PetscErrorCode FVSample_3WaySplit(FVCtx *ctx, DM da, PetscReal time, Vec U)
123: {
124:   PetscScalar   *u, *uj, xj, xi;
125:   PetscInt       i, j, k, dof, xs, xm, Mx;
126:   const PetscInt N = 200;
127:   PetscReal      hs, hm, hf;

129:   PetscFunctionBeginUser;
130:   PetscCheck(ctx->physics2.sample2, PETSC_COMM_SELF, PETSC_ERR_SUP, "Physics has not provided a sampling function");
131:   PetscCall(DMDAGetInfo(da, NULL, &Mx, NULL, NULL, NULL, NULL, NULL, &dof, NULL, NULL, NULL, NULL, NULL));
132:   PetscCall(DMDAGetCorners(da, &xs, NULL, NULL, &xm, NULL, NULL));
133:   PetscCall(DMDAVecGetArray(da, U, &u));
134:   PetscCall(PetscMalloc1(dof, &uj));

136:   hs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
137:   hm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
138:   hf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
139:   for (i = xs; i < xs + xm; i++) {
140:     if (i < ctx->sm) {
141:       xi = ctx->xmin + 0.5 * hs + i * hs;
142:       /* Integrate over cell i using trapezoid rule with N points. */
143:       for (k = 0; k < dof; k++) u[i * dof + k] = 0;
144:       for (j = 0; j < N + 1; j++) {
145:         xj = xi + hs * (j - N / 2) / (PetscReal)N;
146:         PetscCall((*ctx->physics2.sample2)(ctx->physics2.user, ctx->initial, ctx->bctype, ctx->xmin, ctx->xmax, time, xj, uj));
147:         for (k = 0; k < dof; k++) u[i * dof + k] += ((j == 0 || j == N) ? 0.5 : 1.0) * uj[k] / N;
148:       }
149:     } else if (i < ctx->mf) {
150:       xi = ctx->xmin + ctx->sm * hs + 0.5 * hm + (i - ctx->sm) * hm;
151:       /* Integrate over cell i using trapezoid rule with N points. */
152:       for (k = 0; k < dof; k++) u[i * dof + k] = 0;
153:       for (j = 0; j < N + 1; j++) {
154:         xj = xi + hm * (j - N / 2) / (PetscReal)N;
155:         PetscCall((*ctx->physics2.sample2)(ctx->physics2.user, ctx->initial, ctx->bctype, ctx->xmin, ctx->xmax, time, xj, uj));
156:         for (k = 0; k < dof; k++) u[i * dof + k] += ((j == 0 || j == N) ? 0.5 : 1.0) * uj[k] / N;
157:       }
158:     } else if (i < ctx->fm) {
159:       xi = ctx->xmin + ctx->sm * hs + (ctx->mf - ctx->sm) * hm + 0.5 * hf + (i - ctx->mf) * hf;
160:       /* Integrate over cell i using trapezoid rule with N points. */
161:       for (k = 0; k < dof; k++) u[i * dof + k] = 0;
162:       for (j = 0; j < N + 1; j++) {
163:         xj = xi + hf * (j - N / 2) / (PetscReal)N;
164:         PetscCall((*ctx->physics2.sample2)(ctx->physics2.user, ctx->initial, ctx->bctype, ctx->xmin, ctx->xmax, time, xj, uj));
165:         for (k = 0; k < dof; k++) u[i * dof + k] += ((j == 0 || j == N) ? 0.5 : 1.0) * uj[k] / N;
166:       }
167:     } else if (i < ctx->ms) {
168:       xi = ctx->xmin + ctx->sm * hs + (ctx->mf - ctx->sm) * hm + (ctx->fm - ctx->mf) * hf + 0.5 * hm + (i - ctx->fm) * hm;
169:       /* Integrate over cell i using trapezoid rule with N points. */
170:       for (k = 0; k < dof; k++) u[i * dof + k] = 0;
171:       for (j = 0; j < N + 1; j++) {
172:         xj = xi + hm * (j - N / 2) / (PetscReal)N;
173:         PetscCall((*ctx->physics2.sample2)(ctx->physics2.user, ctx->initial, ctx->bctype, ctx->xmin, ctx->xmax, time, xj, uj));
174:         for (k = 0; k < dof; k++) u[i * dof + k] += ((j == 0 || j == N) ? 0.5 : 1.0) * uj[k] / N;
175:       }
176:     } else {
177:       xi = ctx->xmin + ctx->sm * hs + (ctx->mf - ctx->sm) * hm + (ctx->fm - ctx->mf) * hf + (ctx->ms - ctx->fm) * hm + 0.5 * hs + (i - ctx->ms) * hs;
178:       /* Integrate over cell i using trapezoid rule with N points. */
179:       for (k = 0; k < dof; k++) u[i * dof + k] = 0;
180:       for (j = 0; j < N + 1; j++) {
181:         xj = xi + hs * (j - N / 2) / (PetscReal)N;
182:         PetscCall((*ctx->physics2.sample2)(ctx->physics2.user, ctx->initial, ctx->bctype, ctx->xmin, ctx->xmax, time, xj, uj));
183:         for (k = 0; k < dof; k++) u[i * dof + k] += ((j == 0 || j == N) ? 0.5 : 1.0) * uj[k] / N;
184:       }
185:     }
186:   }
187:   PetscCall(DMDAVecRestoreArray(da, U, &u));
188:   PetscCall(PetscFree(uj));
189:   PetscFunctionReturn(PETSC_SUCCESS);
190: }

192: static PetscErrorCode SolutionErrorNorms_3WaySplit(FVCtx *ctx, DM da, PetscReal t, Vec X, PetscReal *nrm1)
193: {
194:   Vec                Y;
195:   PetscInt           i, Mx;
196:   const PetscScalar *ptr_X, *ptr_Y;
197:   PetscReal          hs, hm, hf;

199:   PetscFunctionBeginUser;
200:   PetscCall(VecGetSize(X, &Mx));
201:   hs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
202:   hm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
203:   hf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
204:   PetscCall(VecDuplicate(X, &Y));
205:   PetscCall(FVSample_3WaySplit(ctx, da, t, Y));
206:   PetscCall(VecGetArrayRead(X, &ptr_X));
207:   PetscCall(VecGetArrayRead(Y, &ptr_Y));
208:   for (i = 0; i < Mx; i++) {
209:     if (i < ctx->sm || i > ctx->ms - 1) *nrm1 += hs * PetscAbs(ptr_X[i] - ptr_Y[i]);
210:     else if (i < ctx->mf || i > ctx->fm - 1) *nrm1 += hm * PetscAbs(ptr_X[i] - ptr_Y[i]);
211:     else *nrm1 += hf * PetscAbs(ptr_X[i] - ptr_Y[i]);
212:   }
213:   PetscCall(VecRestoreArrayRead(X, &ptr_X));
214:   PetscCall(VecRestoreArrayRead(Y, &ptr_Y));
215:   PetscCall(VecDestroy(&Y));
216:   PetscFunctionReturn(PETSC_SUCCESS);
217: }

219: PetscErrorCode FVRHSFunction_3WaySplit(TS ts, PetscReal time, Vec X, Vec F, void *vctx)
220: {
221:   FVCtx       *ctx = (FVCtx *)vctx;
222:   PetscInt     i, j, k, Mx, dof, xs, xm, sm = ctx->sm, mf = ctx->mf, fm = ctx->fm, ms = ctx->ms;
223:   PetscReal    hxf, hxm, hxs;
224:   PetscScalar *x, *f, *slope;
225:   Vec          Xloc;
226:   DM           da;

228:   PetscFunctionBeginUser;
229:   ctx->cfl_idt = 0;
230:   PetscCall(TSGetDM(ts, &da));
231:   PetscCall(DMGetLocalVector(da, &Xloc));                                                                  /* Xloc contains ghost points                                     */
232:   PetscCall(DMDAGetInfo(da, NULL, &Mx, NULL, NULL, NULL, NULL, NULL, &dof, NULL, NULL, NULL, NULL, NULL)); /* Mx is the number of center points                              */
233:   hxs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
234:   hxm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
235:   hxf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
236:   PetscCall(DMGlobalToLocalBegin(da, X, INSERT_VALUES, Xloc)); /* X is solution vector which does not contain ghost points       */
237:   PetscCall(DMGlobalToLocalEnd(da, X, INSERT_VALUES, Xloc));

239:   PetscCall(VecZeroEntries(F)); /* F is the right-hand side function corresponds to center points */

241:   PetscCall(DMDAVecGetArray(da, Xloc, &x));
242:   PetscCall(DMDAVecGetArray(da, F, &f));
243:   PetscCall(DMDAGetArray(da, PETSC_TRUE, &slope)); /* contains ghost points                                           */

245:   PetscCall(DMDAGetCorners(da, &xs, NULL, NULL, &xm, NULL, NULL));

247:   if (ctx->bctype == FVBC_OUTFLOW) {
248:     for (i = xs - 2; i < 0; i++) {
249:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
250:     }
251:     for (i = Mx; i < xs + xm + 2; i++) {
252:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
253:     }
254:   }
255:   for (i = xs - 1; i < xs + xm + 1; i++) {
256:     struct _LimitInfo info;
257:     PetscScalar      *cjmpL, *cjmpR;
258:     /* Determine the right eigenvectors R, where A = R \Lambda R^{-1} */
259:     PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
260:     /* Evaluate jumps across interfaces (i-1, i) and (i, i+1), put in characteristic basis */
261:     PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
262:     cjmpL = &ctx->cjmpLR[0];
263:     cjmpR = &ctx->cjmpLR[dof];
264:     for (j = 0; j < dof; j++) {
265:       PetscScalar jmpL, jmpR;
266:       jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
267:       jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
268:       for (k = 0; k < dof; k++) {
269:         cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
270:         cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
271:       }
272:     }
273:     /* Apply limiter to the left and right characteristic jumps */
274:     info.m   = dof;
275:     info.hxs = hxs;
276:     info.hxm = hxm;
277:     info.hxf = hxf;
278:     (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
279:     for (j = 0; j < dof; j++) {
280:       PetscScalar tmp = 0;
281:       for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
282:       slope[i * dof + j] = tmp;
283:     }
284:   }

286:   for (i = xs; i < xs + xm + 1; i++) {
287:     PetscReal    maxspeed;
288:     PetscScalar *uL, *uR;
289:     uL = &ctx->uLR[0];
290:     uR = &ctx->uLR[dof];
291:     if (i < sm || i > ms) { /* slow region */
292:       for (j = 0; j < dof; j++) {
293:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
294:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
295:       }
296:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
297:       if (i > xs) {
298:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxs;
299:       }
300:       if (i < xs + xm) {
301:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxs;
302:       }
303:     } else if (i == sm) { /* interface between slow and medium component */
304:       for (j = 0; j < dof; j++) {
305:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
306:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
307:       }
308:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
309:       if (i > xs) {
310:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxs;
311:       }
312:       if (i < xs + xm) {
313:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxm;
314:       }
315:     } else if (i == ms) { /* interface between medium and slow regions */
316:       for (j = 0; j < dof; j++) {
317:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
318:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
319:       }
320:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
321:       if (i > xs) {
322:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxm;
323:       }
324:       if (i < xs + xm) {
325:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxs;
326:       }
327:     } else if (i < mf || i > fm) { /* medium region */
328:       for (j = 0; j < dof; j++) {
329:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
330:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
331:       }
332:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
333:       if (i > xs) {
334:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxm;
335:       }
336:       if (i < xs + xm) {
337:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxm;
338:       }
339:     } else if (i == mf) { /* interface between medium and fast regions */
340:       for (j = 0; j < dof; j++) {
341:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
342:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxf / 2;
343:       }
344:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
345:       if (i > xs) {
346:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxm;
347:       }
348:       if (i < xs + xm) {
349:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxf;
350:       }
351:     } else if (i == fm) { /* interface between fast and medium regions */
352:       for (j = 0; j < dof; j++) {
353:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxf / 2;
354:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
355:       }
356:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
357:       if (i > xs) {
358:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxf;
359:       }
360:       if (i < xs + xm) {
361:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxm;
362:       }
363:     } else { /* fast region */
364:       for (j = 0; j < dof; j++) {
365:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxf / 2;
366:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxf / 2;
367:       }
368:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
369:       ctx->cfl_idt = PetscMax(ctx->cfl_idt, PetscAbsScalar(maxspeed / hxs)); /* Max allowable value of 1/Delta t */
370:       if (i > xs) {
371:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxf;
372:       }
373:       if (i < xs + xm) {
374:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxf;
375:       }
376:     }
377:   }
378:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
379:   PetscCall(DMDAVecRestoreArray(da, F, &f));
380:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
381:   PetscCall(DMRestoreLocalVector(da, &Xloc));
382:   PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &ctx->cfl_idt, 1, MPIU_SCALAR, MPIU_MAX, PetscObjectComm((PetscObject)da)));
383:   if (0) {
384:     /* We need to a way to inform the TS of a CFL constraint, this is a debugging fragment */
385:     PetscReal dt, tnow;
386:     PetscCall(TSGetTimeStep(ts, &dt));
387:     PetscCall(TSGetTime(ts, &tnow));
388:     if (dt > 0.5 / ctx->cfl_idt) PetscCall(PetscPrintf(ctx->comm, "Stability constraint exceeded at t=%g, dt %g > %g\n", (double)tnow, (double)dt, (double)(1 / (2 * ctx->cfl_idt))));
389:   }
390:   PetscFunctionReturn(PETSC_SUCCESS);
391: }

393: /* --------------------------------- Finite Volume Solver for slow components ----------------------------------- */
394: PetscErrorCode FVRHSFunctionslow_3WaySplit(TS ts, PetscReal time, Vec X, Vec F, void *vctx)
395: {
396:   FVCtx       *ctx = (FVCtx *)vctx;
397:   PetscInt     i, j, k, Mx, dof, xs, xm, islow = 0, sm = ctx->sm, ms = ctx->ms, lsbwidth = ctx->lsbwidth, rsbwidth = ctx->rsbwidth;
398:   PetscReal    hxs, hxm, hxf;
399:   PetscScalar *x, *f, *slope;
400:   Vec          Xloc;
401:   DM           da;

403:   PetscFunctionBeginUser;
404:   ctx->cfl_idt = 0;
405:   PetscCall(TSGetDM(ts, &da));
406:   PetscCall(DMGetLocalVector(da, &Xloc));
407:   PetscCall(DMDAGetInfo(da, NULL, &Mx, NULL, NULL, NULL, NULL, NULL, &dof, NULL, NULL, NULL, NULL, NULL));
408:   hxs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
409:   hxm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
410:   hxf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
411:   PetscCall(DMGlobalToLocalBegin(da, X, INSERT_VALUES, Xloc));
412:   PetscCall(DMGlobalToLocalEnd(da, X, INSERT_VALUES, Xloc));
413:   PetscCall(VecZeroEntries(F));
414:   PetscCall(DMDAVecGetArray(da, Xloc, &x));
415:   PetscCall(VecGetArray(F, &f));
416:   PetscCall(DMDAGetArray(da, PETSC_TRUE, &slope));
417:   PetscCall(DMDAGetCorners(da, &xs, NULL, NULL, &xm, NULL, NULL));

419:   if (ctx->bctype == FVBC_OUTFLOW) {
420:     for (i = xs - 2; i < 0; i++) {
421:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
422:     }
423:     for (i = Mx; i < xs + xm + 2; i++) {
424:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
425:     }
426:   }
427:   for (i = xs - 1; i < xs + xm + 1; i++) {
428:     struct _LimitInfo info;
429:     PetscScalar      *cjmpL, *cjmpR;
430:     if (i < sm - lsbwidth + 1 || i > ms + rsbwidth - 2) { /* slow components and the first and last fast components */
431:       /* Determine the right eigenvectors R, where A = R \Lambda R^{-1} */
432:       PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
433:       /* Evaluate jumps across interfaces (i-1, i) and (i, i+1), put in characteristic basis */
434:       PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
435:       cjmpL = &ctx->cjmpLR[0];
436:       cjmpR = &ctx->cjmpLR[dof];
437:       for (j = 0; j < dof; j++) {
438:         PetscScalar jmpL, jmpR;
439:         jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
440:         jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
441:         for (k = 0; k < dof; k++) {
442:           cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
443:           cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
444:         }
445:       }
446:       /* Apply limiter to the left and right characteristic jumps */
447:       info.m   = dof;
448:       info.hxs = hxs;
449:       info.hxm = hxm;
450:       info.hxf = hxf;
451:       (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
452:       for (j = 0; j < dof; j++) {
453:         PetscScalar tmp = 0;
454:         for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
455:         slope[i * dof + j] = tmp;
456:       }
457:     }
458:   }

460:   for (i = xs; i < xs + xm + 1; i++) {
461:     PetscReal    maxspeed;
462:     PetscScalar *uL, *uR;
463:     uL = &ctx->uLR[0];
464:     uR = &ctx->uLR[dof];
465:     if (i < sm - lsbwidth) { /* slow region */
466:       for (j = 0; j < dof; j++) {
467:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
468:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
469:       }
470:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
471:       ctx->cfl_idt = PetscMax(ctx->cfl_idt, PetscAbsScalar(maxspeed / hxs)); /* Max allowable value of 1/Delta t */
472:       if (i > xs) {
473:         for (j = 0; j < dof; j++) f[(islow - 1) * dof + j] -= ctx->flux[j] / hxs;
474:       }
475:       if (i < xs + xm) {
476:         for (j = 0; j < dof; j++) f[islow * dof + j] += ctx->flux[j] / hxs;
477:         islow++;
478:       }
479:     }
480:     if (i == sm - lsbwidth) { /* interface between slow and medium regions */
481:       for (j = 0; j < dof; j++) {
482:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
483:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
484:       }
485:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
486:       if (i > xs) {
487:         for (j = 0; j < dof; j++) f[(islow - 1) * dof + j] -= ctx->flux[j] / hxs;
488:       }
489:     }
490:     if (i == ms + rsbwidth) { /* interface between medium and slow regions */
491:       for (j = 0; j < dof; j++) {
492:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
493:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
494:       }
495:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
496:       if (i < xs + xm) {
497:         for (j = 0; j < dof; j++) f[islow * dof + j] += ctx->flux[j] / hxs;
498:         islow++;
499:       }
500:     }
501:     if (i > ms + rsbwidth) { /* slow region */
502:       for (j = 0; j < dof; j++) {
503:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
504:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
505:       }
506:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
507:       ctx->cfl_idt = PetscMax(ctx->cfl_idt, PetscAbsScalar(maxspeed / hxs)); /* Max allowable value of 1/Delta t */
508:       if (i > xs) {
509:         for (j = 0; j < dof; j++) f[(islow - 1) * dof + j] -= ctx->flux[j] / hxs;
510:       }
511:       if (i < xs + xm) {
512:         for (j = 0; j < dof; j++) f[islow * dof + j] += ctx->flux[j] / hxs;
513:         islow++;
514:       }
515:     }
516:   }
517:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
518:   PetscCall(VecRestoreArray(F, &f));
519:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
520:   PetscCall(DMRestoreLocalVector(da, &Xloc));
521:   PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &ctx->cfl_idt, 1, MPIU_SCALAR, MPIU_MAX, PetscObjectComm((PetscObject)da)));
522:   PetscFunctionReturn(PETSC_SUCCESS);
523: }

525: PetscErrorCode FVRHSFunctionslowbuffer_3WaySplit(TS ts, PetscReal time, Vec X, Vec F, void *vctx)
526: {
527:   FVCtx       *ctx = (FVCtx *)vctx;
528:   PetscInt     i, j, k, Mx, dof, xs, xm, islowbuffer = 0, sm = ctx->sm, ms = ctx->ms, lsbwidth = ctx->lsbwidth, rsbwidth = ctx->rsbwidth;
529:   PetscReal    hxs, hxm, hxf;
530:   PetscScalar *x, *f, *slope;
531:   Vec          Xloc;
532:   DM           da;

534:   PetscFunctionBeginUser;
535:   PetscCall(TSGetDM(ts, &da));
536:   PetscCall(DMGetLocalVector(da, &Xloc));
537:   PetscCall(DMDAGetInfo(da, NULL, &Mx, NULL, NULL, NULL, NULL, NULL, &dof, NULL, NULL, NULL, NULL, NULL));
538:   hxs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
539:   hxm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
540:   hxf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
541:   PetscCall(DMGlobalToLocalBegin(da, X, INSERT_VALUES, Xloc));
542:   PetscCall(DMGlobalToLocalEnd(da, X, INSERT_VALUES, Xloc));
543:   PetscCall(VecZeroEntries(F));
544:   PetscCall(DMDAVecGetArray(da, Xloc, &x));
545:   PetscCall(VecGetArray(F, &f));
546:   PetscCall(DMDAGetArray(da, PETSC_TRUE, &slope));
547:   PetscCall(DMDAGetCorners(da, &xs, NULL, NULL, &xm, NULL, NULL));

549:   if (ctx->bctype == FVBC_OUTFLOW) {
550:     for (i = xs - 2; i < 0; i++) {
551:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
552:     }
553:     for (i = Mx; i < xs + xm + 2; i++) {
554:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
555:     }
556:   }
557:   for (i = xs - 1; i < xs + xm + 1; i++) {
558:     struct _LimitInfo info;
559:     PetscScalar      *cjmpL, *cjmpR;
560:     if ((i > sm - lsbwidth - 2 && i < sm + 1) || (i > ms - 2 && i < ms + rsbwidth + 1)) {
561:       /* Determine the right eigenvectors R, where A = R \Lambda R^{-1} */
562:       PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
563:       /* Evaluate jumps across interfaces (i-1, i) and (i, i+1), put in characteristic basis */
564:       PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
565:       cjmpL = &ctx->cjmpLR[0];
566:       cjmpR = &ctx->cjmpLR[dof];
567:       for (j = 0; j < dof; j++) {
568:         PetscScalar jmpL, jmpR;
569:         jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
570:         jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
571:         for (k = 0; k < dof; k++) {
572:           cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
573:           cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
574:         }
575:       }
576:       /* Apply limiter to the left and right characteristic jumps */
577:       info.m   = dof;
578:       info.hxs = hxs;
579:       info.hxm = hxm;
580:       info.hxf = hxf;
581:       (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
582:       for (j = 0; j < dof; j++) {
583:         PetscScalar tmp = 0;
584:         for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
585:         slope[i * dof + j] = tmp;
586:       }
587:     }
588:   }

590:   for (i = xs; i < xs + xm + 1; i++) {
591:     PetscReal    maxspeed;
592:     PetscScalar *uL, *uR;
593:     uL = &ctx->uLR[0];
594:     uR = &ctx->uLR[dof];
595:     if (i == sm - lsbwidth) {
596:       for (j = 0; j < dof; j++) {
597:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
598:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
599:       }
600:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
601:       if (i < xs + xm) {
602:         for (j = 0; j < dof; j++) f[islowbuffer * dof + j] += ctx->flux[j] / hxs;
603:         islowbuffer++;
604:       }
605:     }
606:     if (i > sm - lsbwidth && i < sm) {
607:       for (j = 0; j < dof; j++) {
608:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
609:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
610:       }
611:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
612:       if (i > xs) {
613:         for (j = 0; j < dof; j++) f[(islowbuffer - 1) * dof + j] -= ctx->flux[j] / hxs;
614:       }
615:       if (i < xs + xm) {
616:         for (j = 0; j < dof; j++) f[islowbuffer * dof + j] += ctx->flux[j] / hxs;
617:         islowbuffer++;
618:       }
619:     }
620:     if (i == sm) { /* interface between the slow region and the medium region */
621:       for (j = 0; j < dof; j++) {
622:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
623:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
624:       }
625:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
626:       if (i > xs) {
627:         for (j = 0; j < dof; j++) f[(islowbuffer - 1) * dof + j] -= ctx->flux[j] / hxs;
628:       }
629:     }
630:     if (i == ms) { /* interface between the medium region and the slow region */
631:       for (j = 0; j < dof; j++) {
632:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
633:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
634:       }
635:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
636:       if (i < xs + xm) {
637:         for (j = 0; j < dof; j++) f[islowbuffer * dof + j] += ctx->flux[j] / hxs;
638:         islowbuffer++;
639:       }
640:     }
641:     if (i > ms && i < ms + rsbwidth) {
642:       for (j = 0; j < dof; j++) {
643:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
644:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
645:       }
646:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
647:       if (i > xs) {
648:         for (j = 0; j < dof; j++) f[(islowbuffer - 1) * dof + j] -= ctx->flux[j] / hxs;
649:       }
650:       if (i < xs + xm) {
651:         for (j = 0; j < dof; j++) f[islowbuffer * dof + j] += ctx->flux[j] / hxs;
652:         islowbuffer++;
653:       }
654:     }
655:     if (i == ms + rsbwidth) {
656:       for (j = 0; j < dof; j++) {
657:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
658:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
659:       }
660:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
661:       if (i > xs) {
662:         for (j = 0; j < dof; j++) f[(islowbuffer - 1) * dof + j] -= ctx->flux[j] / hxs;
663:       }
664:     }
665:   }
666:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
667:   PetscCall(VecRestoreArray(F, &f));
668:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
669:   PetscCall(DMRestoreLocalVector(da, &Xloc));
670:   PetscFunctionReturn(PETSC_SUCCESS);
671: }

673: /* --------------------------------- Finite Volume Solver for medium components ----------------------------------- */
674: PetscErrorCode FVRHSFunctionmedium_3WaySplit(TS ts, PetscReal time, Vec X, Vec F, void *vctx)
675: {
676:   FVCtx       *ctx = (FVCtx *)vctx;
677:   PetscInt     i, j, k, Mx, dof, xs, xm, imedium = 0, sm = ctx->sm, mf = ctx->mf, fm = ctx->fm, ms = ctx->ms, lmbwidth = ctx->lmbwidth, rmbwidth = ctx->rmbwidth;
678:   PetscReal    hxs, hxm, hxf;
679:   PetscScalar *x, *f, *slope;
680:   Vec          Xloc;
681:   DM           da;

683:   PetscFunctionBeginUser;
684:   PetscCall(TSGetDM(ts, &da));
685:   PetscCall(DMGetLocalVector(da, &Xloc));
686:   PetscCall(DMDAGetInfo(da, NULL, &Mx, NULL, NULL, NULL, NULL, NULL, &dof, NULL, NULL, NULL, NULL, NULL));
687:   hxs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
688:   hxm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
689:   hxf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
690:   PetscCall(DMGlobalToLocalBegin(da, X, INSERT_VALUES, Xloc));
691:   PetscCall(DMGlobalToLocalEnd(da, X, INSERT_VALUES, Xloc));
692:   PetscCall(VecZeroEntries(F));
693:   PetscCall(DMDAVecGetArray(da, Xloc, &x));
694:   PetscCall(VecGetArray(F, &f));
695:   PetscCall(DMDAGetArray(da, PETSC_TRUE, &slope));
696:   PetscCall(DMDAGetCorners(da, &xs, NULL, NULL, &xm, NULL, NULL));

698:   if (ctx->bctype == FVBC_OUTFLOW) {
699:     for (i = xs - 2; i < 0; i++) {
700:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
701:     }
702:     for (i = Mx; i < xs + xm + 2; i++) {
703:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
704:     }
705:   }
706:   for (i = xs - 1; i < xs + xm + 1; i++) {
707:     struct _LimitInfo info;
708:     PetscScalar      *cjmpL, *cjmpR;
709:     if ((i > sm - 2 && i < mf - lmbwidth + 1) || (i > fm + rmbwidth - 2 && i < ms + 1)) { /* slow components and the first and last fast components */
710:       /* Determine the right eigenvectors R, where A = R \Lambda R^{-1} */
711:       PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
712:       /* Evaluate jumps across interfaces (i-1, i) and (i, i+1), put in characteristic basis */
713:       PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
714:       cjmpL = &ctx->cjmpLR[0];
715:       cjmpR = &ctx->cjmpLR[dof];
716:       for (j = 0; j < dof; j++) {
717:         PetscScalar jmpL, jmpR;
718:         jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
719:         jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
720:         for (k = 0; k < dof; k++) {
721:           cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
722:           cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
723:         }
724:       }
725:       /* Apply limiter to the left and right characteristic jumps */
726:       info.m   = dof;
727:       info.hxs = hxs;
728:       info.hxm = hxm;
729:       info.hxf = hxf;
730:       (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
731:       for (j = 0; j < dof; j++) {
732:         PetscScalar tmp = 0;
733:         for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
734:         slope[i * dof + j] = tmp;
735:       }
736:     }
737:   }

739:   for (i = xs; i < xs + xm + 1; i++) {
740:     PetscReal    maxspeed;
741:     PetscScalar *uL, *uR;
742:     uL = &ctx->uLR[0];
743:     uR = &ctx->uLR[dof];
744:     if (i == sm) { /* interface between slow and medium regions */
745:       for (j = 0; j < dof; j++) {
746:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
747:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
748:       }
749:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
750:       if (i < xs + xm) {
751:         for (j = 0; j < dof; j++) f[imedium * dof + j] += ctx->flux[j] / hxm;
752:         imedium++;
753:       }
754:     }
755:     if (i > sm && i < mf - lmbwidth) { /* medium region */
756:       for (j = 0; j < dof; j++) {
757:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
758:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
759:       }
760:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
761:       if (i > xs) {
762:         for (j = 0; j < dof; j++) f[(imedium - 1) * dof + j] -= ctx->flux[j] / hxm;
763:       }
764:       if (i < xs + xm) {
765:         for (j = 0; j < dof; j++) f[imedium * dof + j] += ctx->flux[j] / hxm;
766:         imedium++;
767:       }
768:     }
769:     if (i == mf - lmbwidth) { /* interface between medium and fast regions */
770:       for (j = 0; j < dof; j++) {
771:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
772:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
773:       }
774:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
775:       if (i > xs) {
776:         for (j = 0; j < dof; j++) f[(imedium - 1) * dof + j] -= ctx->flux[j] / hxm;
777:       }
778:     }
779:     if (i == fm + rmbwidth) { /* interface between fast and medium regions */
780:       for (j = 0; j < dof; j++) {
781:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
782:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
783:       }
784:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
785:       if (i < xs + xm) {
786:         for (j = 0; j < dof; j++) f[imedium * dof + j] += ctx->flux[j] / hxm;
787:         imedium++;
788:       }
789:     }
790:     if (i > fm + rmbwidth && i < ms) { /* medium region */
791:       for (j = 0; j < dof; j++) {
792:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
793:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
794:       }
795:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
796:       if (i > xs) {
797:         for (j = 0; j < dof; j++) f[(imedium - 1) * dof + j] -= ctx->flux[j] / hxm;
798:       }
799:       if (i < xs + xm) {
800:         for (j = 0; j < dof; j++) f[imedium * dof + j] += ctx->flux[j] / hxm;
801:         imedium++;
802:       }
803:     }
804:     if (i == ms) { /* interface between medium and slow regions */
805:       for (j = 0; j < dof; j++) {
806:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
807:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
808:       }
809:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
810:       if (i > xs) {
811:         for (j = 0; j < dof; j++) f[(imedium - 1) * dof + j] -= ctx->flux[j] / hxm;
812:       }
813:     }
814:   }
815:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
816:   PetscCall(VecRestoreArray(F, &f));
817:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
818:   PetscCall(DMRestoreLocalVector(da, &Xloc));
819:   PetscFunctionReturn(PETSC_SUCCESS);
820: }

822: PetscErrorCode FVRHSFunctionmediumbuffer_3WaySplit(TS ts, PetscReal time, Vec X, Vec F, void *vctx)
823: {
824:   FVCtx       *ctx = (FVCtx *)vctx;
825:   PetscInt     i, j, k, Mx, dof, xs, xm, imediumbuffer = 0, mf = ctx->mf, fm = ctx->fm, lmbwidth = ctx->lmbwidth, rmbwidth = ctx->rmbwidth;
826:   PetscReal    hxs, hxm, hxf;
827:   PetscScalar *x, *f, *slope;
828:   Vec          Xloc;
829:   DM           da;

831:   PetscFunctionBeginUser;
832:   PetscCall(TSGetDM(ts, &da));
833:   PetscCall(DMGetLocalVector(da, &Xloc));
834:   PetscCall(DMDAGetInfo(da, NULL, &Mx, NULL, NULL, NULL, NULL, NULL, &dof, NULL, NULL, NULL, NULL, NULL));
835:   hxs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
836:   hxm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
837:   hxf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
838:   PetscCall(DMGlobalToLocalBegin(da, X, INSERT_VALUES, Xloc));
839:   PetscCall(DMGlobalToLocalEnd(da, X, INSERT_VALUES, Xloc));
840:   PetscCall(VecZeroEntries(F));
841:   PetscCall(DMDAVecGetArray(da, Xloc, &x));
842:   PetscCall(VecGetArray(F, &f));
843:   PetscCall(DMDAGetArray(da, PETSC_TRUE, &slope));
844:   PetscCall(DMDAGetCorners(da, &xs, NULL, NULL, &xm, NULL, NULL));

846:   if (ctx->bctype == FVBC_OUTFLOW) {
847:     for (i = xs - 2; i < 0; i++) {
848:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
849:     }
850:     for (i = Mx; i < xs + xm + 2; i++) {
851:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
852:     }
853:   }
854:   for (i = xs - 1; i < xs + xm + 1; i++) {
855:     struct _LimitInfo info;
856:     PetscScalar      *cjmpL, *cjmpR;
857:     if ((i > mf - lmbwidth - 2 && i < mf + 1) || (i > fm - 2 && i < fm + rmbwidth + 1)) {
858:       /* Determine the right eigenvectors R, where A = R \Lambda R^{-1} */
859:       PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
860:       /* Evaluate jumps across interfaces (i-1, i) and (i, i+1), put in characteristic basis */
861:       PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
862:       cjmpL = &ctx->cjmpLR[0];
863:       cjmpR = &ctx->cjmpLR[dof];
864:       for (j = 0; j < dof; j++) {
865:         PetscScalar jmpL, jmpR;
866:         jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
867:         jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
868:         for (k = 0; k < dof; k++) {
869:           cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
870:           cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
871:         }
872:       }
873:       /* Apply limiter to the left and right characteristic jumps */
874:       info.m   = dof;
875:       info.hxs = hxs;
876:       info.hxm = hxm;
877:       info.hxf = hxf;
878:       (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
879:       for (j = 0; j < dof; j++) {
880:         PetscScalar tmp = 0;
881:         for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
882:         slope[i * dof + j] = tmp;
883:       }
884:     }
885:   }

887:   for (i = xs; i < xs + xm + 1; i++) {
888:     PetscReal    maxspeed;
889:     PetscScalar *uL, *uR;
890:     uL = &ctx->uLR[0];
891:     uR = &ctx->uLR[dof];
892:     if (i == mf - lmbwidth) {
893:       for (j = 0; j < dof; j++) {
894:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
895:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
896:       }
897:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
898:       if (i < xs + xm) {
899:         for (j = 0; j < dof; j++) f[imediumbuffer * dof + j] += ctx->flux[j] / hxm;
900:         imediumbuffer++;
901:       }
902:     }
903:     if (i > mf - lmbwidth && i < mf) {
904:       for (j = 0; j < dof; j++) {
905:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
906:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
907:       }
908:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
909:       if (i > xs) {
910:         for (j = 0; j < dof; j++) f[(imediumbuffer - 1) * dof + j] -= ctx->flux[j] / hxm;
911:       }
912:       if (i < xs + xm) {
913:         for (j = 0; j < dof; j++) f[imediumbuffer * dof + j] += ctx->flux[j] / hxm;
914:         imediumbuffer++;
915:       }
916:     }
917:     if (i == mf) { /* interface between the medium region and the fast region */
918:       for (j = 0; j < dof; j++) {
919:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
920:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxf / 2;
921:       }
922:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
923:       if (i > xs) {
924:         for (j = 0; j < dof; j++) f[(imediumbuffer - 1) * dof + j] -= ctx->flux[j] / hxm;
925:       }
926:     }
927:     if (i == fm) { /* interface between the fast region and the medium region */
928:       for (j = 0; j < dof; j++) {
929:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxf / 2;
930:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
931:       }
932:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
933:       if (i < xs + xm) {
934:         for (j = 0; j < dof; j++) f[imediumbuffer * dof + j] += ctx->flux[j] / hxm;
935:         imediumbuffer++;
936:       }
937:     }
938:     if (i > fm && i < fm + rmbwidth) {
939:       for (j = 0; j < dof; j++) {
940:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
941:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
942:       }
943:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
944:       if (i > xs) {
945:         for (j = 0; j < dof; j++) f[(imediumbuffer - 1) * dof + j] -= ctx->flux[j] / hxm;
946:       }
947:       if (i < xs + xm) {
948:         for (j = 0; j < dof; j++) f[imediumbuffer * dof + j] += ctx->flux[j] / hxm;
949:         imediumbuffer++;
950:       }
951:     }
952:     if (i == fm + rmbwidth) {
953:       for (j = 0; j < dof; j++) {
954:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
955:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
956:       }
957:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
958:       if (i > xs) {
959:         for (j = 0; j < dof; j++) f[(imediumbuffer - 1) * dof + j] -= ctx->flux[j] / hxm;
960:       }
961:     }
962:   }
963:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
964:   PetscCall(VecRestoreArray(F, &f));
965:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
966:   PetscCall(DMRestoreLocalVector(da, &Xloc));
967:   PetscFunctionReturn(PETSC_SUCCESS);
968: }

970: /* --------------------------------- Finite Volume Solver for fast  parts ----------------------------------- */
971: PetscErrorCode FVRHSFunctionfast_3WaySplit(TS ts, PetscReal time, Vec X, Vec F, void *vctx)
972: {
973:   FVCtx       *ctx = (FVCtx *)vctx;
974:   PetscInt     i, j, k, Mx, dof, xs, xm, ifast = 0, mf = ctx->mf, fm = ctx->fm;
975:   PetscReal    hxs, hxm, hxf;
976:   PetscScalar *x, *f, *slope;
977:   Vec          Xloc;
978:   DM           da;

980:   PetscFunctionBeginUser;
981:   PetscCall(TSGetDM(ts, &da));
982:   PetscCall(DMGetLocalVector(da, &Xloc));
983:   PetscCall(DMDAGetInfo(da, NULL, &Mx, NULL, NULL, NULL, NULL, NULL, &dof, NULL, NULL, NULL, NULL, NULL));
984:   hxs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
985:   hxm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
986:   hxf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
987:   PetscCall(DMGlobalToLocalBegin(da, X, INSERT_VALUES, Xloc));
988:   PetscCall(DMGlobalToLocalEnd(da, X, INSERT_VALUES, Xloc));
989:   PetscCall(VecZeroEntries(F));
990:   PetscCall(DMDAVecGetArray(da, Xloc, &x));
991:   PetscCall(VecGetArray(F, &f));
992:   PetscCall(DMDAGetArray(da, PETSC_TRUE, &slope));
993:   PetscCall(DMDAGetCorners(da, &xs, NULL, NULL, &xm, NULL, NULL));

995:   if (ctx->bctype == FVBC_OUTFLOW) {
996:     for (i = xs - 2; i < 0; i++) {
997:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
998:     }
999:     for (i = Mx; i < xs + xm + 2; i++) {
1000:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
1001:     }
1002:   }
1003:   for (i = xs - 1; i < xs + xm + 1; i++) { /* fast components and the last slow components before fast components and the first slow component after fast components */
1004:     struct _LimitInfo info;
1005:     PetscScalar      *cjmpL, *cjmpR;
1006:     if (i > mf - 2 && i < fm + 1) {
1007:       PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
1008:       PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
1009:       cjmpL = &ctx->cjmpLR[0];
1010:       cjmpR = &ctx->cjmpLR[dof];
1011:       for (j = 0; j < dof; j++) {
1012:         PetscScalar jmpL, jmpR;
1013:         jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
1014:         jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
1015:         for (k = 0; k < dof; k++) {
1016:           cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
1017:           cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
1018:         }
1019:       }
1020:       /* Apply limiter to the left and right characteristic jumps */
1021:       info.m   = dof;
1022:       info.hxs = hxs;
1023:       info.hxm = hxm;
1024:       info.hxf = hxf;
1025:       (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
1026:       for (j = 0; j < dof; j++) {
1027:         PetscScalar tmp = 0;
1028:         for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
1029:         slope[i * dof + j] = tmp;
1030:       }
1031:     }
1032:   }

1034:   for (i = xs; i < xs + xm + 1; i++) {
1035:     PetscReal    maxspeed;
1036:     PetscScalar *uL, *uR;
1037:     uL = &ctx->uLR[0];
1038:     uR = &ctx->uLR[dof];
1039:     if (i == mf) { /* interface between medium and fast regions */
1040:       for (j = 0; j < dof; j++) {
1041:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
1042:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxf / 2;
1043:       }
1044:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
1045:       if (i < xs + xm) {
1046:         for (j = 0; j < dof; j++) f[ifast * dof + j] += ctx->flux[j] / hxf;
1047:         ifast++;
1048:       }
1049:     }
1050:     if (i > mf && i < fm) { /* fast region */
1051:       for (j = 0; j < dof; j++) {
1052:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxf / 2;
1053:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxf / 2;
1054:       }
1055:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
1056:       if (i > xs) {
1057:         for (j = 0; j < dof; j++) f[(ifast - 1) * dof + j] -= ctx->flux[j] / hxf;
1058:       }
1059:       if (i < xs + xm) {
1060:         for (j = 0; j < dof; j++) f[ifast * dof + j] += ctx->flux[j] / hxf;
1061:         ifast++;
1062:       }
1063:     }
1064:     if (i == fm) { /* interface between fast and medium regions */
1065:       for (j = 0; j < dof; j++) {
1066:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxf / 2;
1067:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
1068:       }
1069:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
1070:       if (i > xs) {
1071:         for (j = 0; j < dof; j++) f[(ifast - 1) * dof + j] -= ctx->flux[j] / hxf;
1072:       }
1073:     }
1074:   }
1075:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
1076:   PetscCall(VecRestoreArray(F, &f));
1077:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
1078:   PetscCall(DMRestoreLocalVector(da, &Xloc));
1079:   PetscFunctionReturn(PETSC_SUCCESS);
1080: }

1082: int main(int argc, char *argv[])
1083: {
1084:   char              lname[256] = "mc", physname[256] = "advect", final_fname[256] = "solution.m";
1085:   PetscFunctionList limiters = NULL, physics = NULL;
1086:   MPI_Comm          comm;
1087:   TS                ts;
1088:   DM                da;
1089:   Vec               X, X0, R;
1090:   FVCtx             ctx;
1091:   PetscInt          i, k, dof, xs, xm, Mx, draw = 0, count_slow, count_medium, count_fast, islow = 0, imedium = 0, ifast = 0, *index_slow, *index_medium, *index_fast, islowbuffer = 0, *index_slowbuffer, imediumbuffer = 0, *index_mediumbuffer;
1092:   PetscBool         view_final = PETSC_FALSE;
1093:   PetscReal         ptime;

1095:   PetscFunctionBeginUser;
1096:   PetscCall(PetscInitialize(&argc, &argv, NULL, help));
1097:   comm = PETSC_COMM_WORLD;
1098:   PetscCall(PetscMemzero(&ctx, sizeof(ctx)));

1100:   /* Register limiters to be available on the command line */
1101:   PetscCall(PetscFunctionListAdd(&limiters, "upwind", Limit3_Upwind));
1102:   PetscCall(PetscFunctionListAdd(&limiters, "lax-wendroff", Limit3_LaxWendroff));
1103:   PetscCall(PetscFunctionListAdd(&limiters, "beam-warming", Limit3_BeamWarming));
1104:   PetscCall(PetscFunctionListAdd(&limiters, "fromm", Limit3_Fromm));
1105:   PetscCall(PetscFunctionListAdd(&limiters, "minmod", Limit3_Minmod));
1106:   PetscCall(PetscFunctionListAdd(&limiters, "superbee", Limit3_Superbee));
1107:   PetscCall(PetscFunctionListAdd(&limiters, "mc", Limit3_MC));
1108:   PetscCall(PetscFunctionListAdd(&limiters, "koren3", Limit3_Koren3));

1110:   /* Register physical models to be available on the command line */
1111:   PetscCall(PetscFunctionListAdd(&physics, "advect", PhysicsCreate_Advect));

1113:   ctx.comm   = comm;
1114:   ctx.cfl    = 0.9;
1115:   ctx.bctype = FVBC_PERIODIC;
1116:   ctx.xmin   = -1.0;
1117:   ctx.xmax   = 1.0;
1118:   PetscOptionsBegin(comm, NULL, "Finite Volume solver options", "");
1119:   PetscCall(PetscOptionsReal("-xmin", "X min", "", ctx.xmin, &ctx.xmin, NULL));
1120:   PetscCall(PetscOptionsReal("-xmax", "X max", "", ctx.xmax, &ctx.xmax, NULL));
1121:   PetscCall(PetscOptionsFList("-limit", "Name of flux imiter to use", "", limiters, lname, lname, sizeof(lname), NULL));
1122:   PetscCall(PetscOptionsInt("-draw", "Draw solution vector, bitwise OR of (1=initial,2=final,4=final error)", "", draw, &draw, NULL));
1123:   PetscCall(PetscOptionsString("-view_final", "Write final solution in ASCII MATLAB format to given file name", "", final_fname, final_fname, sizeof(final_fname), &view_final));
1124:   PetscCall(PetscOptionsInt("-initial", "Initial condition (depends on the physics)", "", ctx.initial, &ctx.initial, NULL));
1125:   PetscCall(PetscOptionsBool("-exact", "Compare errors with exact solution", "", ctx.exact, &ctx.exact, NULL));
1126:   PetscCall(PetscOptionsBool("-simulation", "Compare errors with reference solution", "", ctx.simulation, &ctx.simulation, NULL));
1127:   PetscCall(PetscOptionsReal("-cfl", "CFL number to time step at", "", ctx.cfl, &ctx.cfl, NULL));
1128:   PetscCall(PetscOptionsEnum("-bc_type", "Boundary condition", "", FVBCTypes, (PetscEnum)ctx.bctype, (PetscEnum *)&ctx.bctype, NULL));
1129:   PetscCall(PetscOptionsInt("-hratio", "Spacing ratio", "", ctx.hratio, &ctx.hratio, NULL));
1130:   PetscOptionsEnd();

1132:   /* Choose the limiter from the list of registered limiters */
1133:   PetscCall(PetscFunctionListFind(limiters, lname, &ctx.limit3));
1134:   PetscCheck(ctx.limit3, PETSC_COMM_SELF, PETSC_ERR_ARG_UNKNOWN_TYPE, "Limiter '%s' not found", lname);

1136:   /* Choose the physics from the list of registered models */
1137:   {
1138:     PetscErrorCode (*r)(FVCtx *);
1139:     PetscCall(PetscFunctionListFind(physics, physname, &r));
1140:     PetscCheck(r, PETSC_COMM_SELF, PETSC_ERR_ARG_UNKNOWN_TYPE, "Physics '%s' not found", physname);
1141:     /* Create the physics, will set the number of fields and their names */
1142:     PetscCall((*r)(&ctx));
1143:   }

1145:   /* Create a DMDA to manage the parallel grid */
1146:   PetscCall(DMDACreate1d(comm, DM_BOUNDARY_PERIODIC, 50, ctx.physics2.dof, 2, NULL, &da));
1147:   PetscCall(DMSetFromOptions(da));
1148:   PetscCall(DMSetUp(da));
1149:   /* Inform the DMDA of the field names provided by the physics. */
1150:   /* The names will be shown in the title bars when run with -ts_monitor_draw_solution */
1151:   for (i = 0; i < ctx.physics2.dof; i++) PetscCall(DMDASetFieldName(da, i, ctx.physics2.fieldname[i]));
1152:   PetscCall(DMDAGetInfo(da, NULL, &Mx, NULL, NULL, NULL, NULL, NULL, &dof, NULL, NULL, NULL, NULL, NULL));
1153:   PetscCall(DMDAGetCorners(da, &xs, NULL, NULL, &xm, NULL, NULL));

1155:   /* Set coordinates of cell centers */
1156:   PetscCall(DMDASetUniformCoordinates(da, ctx.xmin + 0.5 * (ctx.xmax - ctx.xmin) / Mx, ctx.xmax + 0.5 * (ctx.xmax - ctx.xmin) / Mx, 0, 0, 0, 0));

1158:   /* Allocate work space for the Finite Volume solver (so it doesn't have to be reallocated on each function evaluation) */
1159:   PetscCall(PetscMalloc4(dof * dof, &ctx.R, dof * dof, &ctx.Rinv, 2 * dof, &ctx.cjmpLR, 1 * dof, &ctx.cslope));
1160:   PetscCall(PetscMalloc3(2 * dof, &ctx.uLR, dof, &ctx.flux, dof, &ctx.speeds));

1162:   /* Create a vector to store the solution and to save the initial state */
1163:   PetscCall(DMCreateGlobalVector(da, &X));
1164:   PetscCall(VecDuplicate(X, &X0));
1165:   PetscCall(VecDuplicate(X, &R));

1167:   /* create index for slow parts and fast parts,
1168:      count_slow + count_fast = Mx, counts_slow*hs = 0.5, counts_fast*hf = 0.5 */
1169:   count_slow   = Mx / (1 + ctx.hratio) / (1 + ctx.hratio);
1170:   count_medium = 2 * ctx.hratio * count_slow;
1171:   PetscCheck((count_slow % 2) == 0 && (count_medium % 2) == 0, PETSC_COMM_WORLD, PETSC_ERR_USER, "Please adjust grid size Mx (-da_grid_x) and hratio (-hratio) so that Mx/(1+hartio)^2 and Mx*2*hratio/(1+hratio)^2 is even");
1172:   count_fast = ctx.hratio * ctx.hratio * count_slow;
1173:   ctx.sm     = count_slow / 2;
1174:   ctx.mf     = ctx.sm + count_medium / 2;
1175:   ctx.fm     = ctx.mf + count_fast;
1176:   ctx.ms     = ctx.fm + count_medium / 2;
1177:   PetscCall(PetscMalloc1(xm * dof, &index_slow));
1178:   PetscCall(PetscMalloc1(xm * dof, &index_medium));
1179:   PetscCall(PetscMalloc1(xm * dof, &index_fast));
1180:   PetscCall(PetscMalloc1(6 * dof, &index_slowbuffer));
1181:   PetscCall(PetscMalloc1(6 * dof, &index_mediumbuffer));
1182:   if (((AdvectCtx *)ctx.physics2.user)->a > 0) {
1183:     ctx.lsbwidth = 2;
1184:     ctx.rsbwidth = 4;
1185:     ctx.lmbwidth = 2;
1186:     ctx.rmbwidth = 4;
1187:   } else {
1188:     ctx.lsbwidth = 4;
1189:     ctx.rsbwidth = 2;
1190:     ctx.lmbwidth = 4;
1191:     ctx.rmbwidth = 2;
1192:   }

1194:   for (i = xs; i < xs + xm; i++) {
1195:     if (i < ctx.sm - ctx.lsbwidth || i > ctx.ms + ctx.rsbwidth - 1)
1196:       for (k = 0; k < dof; k++) index_slow[islow++] = i * dof + k;
1197:     else if ((i >= ctx.sm - ctx.lsbwidth && i < ctx.sm) || (i > ctx.ms - 1 && i <= ctx.ms + ctx.rsbwidth - 1))
1198:       for (k = 0; k < dof; k++) index_slowbuffer[islowbuffer++] = i * dof + k;
1199:     else if (i < ctx.mf - ctx.lmbwidth || i > ctx.fm + ctx.rmbwidth - 1)
1200:       for (k = 0; k < dof; k++) index_medium[imedium++] = i * dof + k;
1201:     else if ((i >= ctx.mf - ctx.lmbwidth && i < ctx.mf) || (i > ctx.fm - 1 && i <= ctx.fm + ctx.rmbwidth - 1))
1202:       for (k = 0; k < dof; k++) index_mediumbuffer[imediumbuffer++] = i * dof + k;
1203:     else
1204:       for (k = 0; k < dof; k++) index_fast[ifast++] = i * dof + k;
1205:   }
1206:   PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, islow, index_slow, PETSC_COPY_VALUES, &ctx.iss));
1207:   PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, imedium, index_medium, PETSC_COPY_VALUES, &ctx.ism));
1208:   PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, ifast, index_fast, PETSC_COPY_VALUES, &ctx.isf));
1209:   PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, islowbuffer, index_slowbuffer, PETSC_COPY_VALUES, &ctx.issb));
1210:   PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, imediumbuffer, index_mediumbuffer, PETSC_COPY_VALUES, &ctx.ismb));

1212:   /* Create a time-stepping object */
1213:   PetscCall(TSCreate(comm, &ts));
1214:   PetscCall(TSSetDM(ts, da));
1215:   PetscCall(TSSetRHSFunction(ts, R, FVRHSFunction_3WaySplit, &ctx));
1216:   PetscCall(TSRHSSplitSetIS(ts, "slow", ctx.iss));
1217:   PetscCall(TSRHSSplitSetIS(ts, "medium", ctx.ism));
1218:   PetscCall(TSRHSSplitSetIS(ts, "fast", ctx.isf));
1219:   PetscCall(TSRHSSplitSetIS(ts, "slowbuffer", ctx.issb));
1220:   PetscCall(TSRHSSplitSetIS(ts, "mediumbuffer", ctx.ismb));
1221:   PetscCall(TSRHSSplitSetRHSFunction(ts, "slow", NULL, FVRHSFunctionslow_3WaySplit, &ctx));
1222:   PetscCall(TSRHSSplitSetRHSFunction(ts, "medium", NULL, FVRHSFunctionmedium_3WaySplit, &ctx));
1223:   PetscCall(TSRHSSplitSetRHSFunction(ts, "fast", NULL, FVRHSFunctionfast_3WaySplit, &ctx));
1224:   PetscCall(TSRHSSplitSetRHSFunction(ts, "slowbuffer", NULL, FVRHSFunctionslowbuffer_3WaySplit, &ctx));
1225:   PetscCall(TSRHSSplitSetRHSFunction(ts, "mediumbuffer", NULL, FVRHSFunctionmediumbuffer_3WaySplit, &ctx));

1227:   PetscCall(TSSetType(ts, TSSSP));
1228:   /*PetscCall(TSSetType(ts,TSMPRK));*/
1229:   PetscCall(TSSetMaxTime(ts, 10));
1230:   PetscCall(TSSetExactFinalTime(ts, TS_EXACTFINALTIME_STEPOVER));

1232:   /* Compute initial conditions and starting time step */
1233:   PetscCall(FVSample_3WaySplit(&ctx, da, 0, X0));
1234:   PetscCall(FVRHSFunction_3WaySplit(ts, 0, X0, X, (void *)&ctx)); /* Initial function evaluation, only used to determine max speed */
1235:   PetscCall(VecCopy(X0, X));                                      /* The function value was not used so we set X=X0 again */
1236:   PetscCall(TSSetTimeStep(ts, ctx.cfl / ctx.cfl_idt));
1237:   PetscCall(TSSetFromOptions(ts)); /* Take runtime options */
1238:   PetscCall(SolutionStatsView(da, X, PETSC_VIEWER_STDOUT_WORLD));
1239:   {
1240:     PetscInt           steps;
1241:     PetscScalar        mass_initial, mass_final, mass_difference;
1242:     const PetscScalar *ptr_X, *ptr_X0;
1243:     const PetscReal    hs = (ctx.xmax - ctx.xmin) / 4.0 / count_slow;
1244:     const PetscReal    hm = (ctx.xmax - ctx.xmin) / 2.0 / count_medium;
1245:     const PetscReal    hf = (ctx.xmax - ctx.xmin) / 4.0 / count_fast;

1247:     PetscCall(TSSolve(ts, X));
1248:     PetscCall(TSGetSolveTime(ts, &ptime));
1249:     PetscCall(TSGetStepNumber(ts, &steps));
1250:     /* calculate the total mass at initial time and final time */
1251:     mass_initial = 0.0;
1252:     mass_final   = 0.0;
1253:     PetscCall(DMDAVecGetArrayRead(da, X0, (void *)&ptr_X0));
1254:     PetscCall(DMDAVecGetArrayRead(da, X, (void *)&ptr_X));
1255:     for (i = xs; i < xs + xm; i++) {
1256:       if (i < ctx.sm || i > ctx.ms - 1)
1257:         for (k = 0; k < dof; k++) {
1258:           mass_initial = mass_initial + hs * ptr_X0[i * dof + k];
1259:           mass_final   = mass_final + hs * ptr_X[i * dof + k];
1260:         }
1261:       else if (i < ctx.mf || i > ctx.fm - 1)
1262:         for (k = 0; k < dof; k++) {
1263:           mass_initial = mass_initial + hm * ptr_X0[i * dof + k];
1264:           mass_final   = mass_final + hm * ptr_X[i * dof + k];
1265:         }
1266:       else {
1267:         for (k = 0; k < dof; k++) {
1268:           mass_initial = mass_initial + hf * ptr_X0[i * dof + k];
1269:           mass_final   = mass_final + hf * ptr_X[i * dof + k];
1270:         }
1271:       }
1272:     }
1273:     PetscCall(DMDAVecRestoreArrayRead(da, X0, (void *)&ptr_X0));
1274:     PetscCall(DMDAVecRestoreArrayRead(da, X, (void *)&ptr_X));
1275:     mass_difference = mass_final - mass_initial;
1276:     PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &mass_difference, 1, MPIU_SCALAR, MPIU_SUM, comm));
1277:     PetscCall(PetscPrintf(comm, "Mass difference %g\n", (double)mass_difference));
1278:     PetscCall(PetscPrintf(comm, "Final time %g, steps %" PetscInt_FMT "\n", (double)ptime, steps));
1279:     PetscCall(PetscPrintf(comm, "Maximum allowable stepsize according to CFL %g\n", (double)(1 / ctx.cfl_idt)));
1280:     if (ctx.exact) {
1281:       PetscReal nrm1 = 0;
1282:       PetscCall(SolutionErrorNorms_3WaySplit(&ctx, da, ptime, X, &nrm1));
1283:       PetscCall(PetscPrintf(comm, "Error ||x-x_e||_1 %g\n", (double)nrm1));
1284:     }
1285:     if (ctx.simulation) {
1286:       PetscReal          nrm1 = 0;
1287:       PetscViewer        fd;
1288:       char               filename[PETSC_MAX_PATH_LEN] = "binaryoutput";
1289:       Vec                XR;
1290:       PetscBool          flg;
1291:       const PetscScalar *ptr_XR;
1292:       PetscCall(PetscOptionsGetString(NULL, NULL, "-f", filename, sizeof(filename), &flg));
1293:       PetscCheck(flg, PETSC_COMM_WORLD, PETSC_ERR_USER, "Must indicate binary file with the -f option");
1294:       PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, filename, FILE_MODE_READ, &fd));
1295:       PetscCall(VecDuplicate(X0, &XR));
1296:       PetscCall(VecLoad(XR, fd));
1297:       PetscCall(PetscViewerDestroy(&fd));
1298:       PetscCall(VecGetArrayRead(X, &ptr_X));
1299:       PetscCall(VecGetArrayRead(XR, &ptr_XR));
1300:       for (i = xs; i < xs + xm; i++) {
1301:         if (i < ctx.sm || i > ctx.ms - 1)
1302:           for (k = 0; k < dof; k++) nrm1 = nrm1 + hs * PetscAbs(ptr_X[i * dof + k] - ptr_XR[i * dof + k]);
1303:         else if (i < ctx.mf || i < ctx.fm - 1)
1304:           for (k = 0; k < dof; k++) nrm1 = nrm1 + hm * PetscAbs(ptr_X[i * dof + k] - ptr_XR[i * dof + k]);
1305:         else
1306:           for (k = 0; k < dof; k++) nrm1 = nrm1 + hf * PetscAbs(ptr_X[i * dof + k] - ptr_XR[i * dof + k]);
1307:       }
1308:       PetscCall(VecRestoreArrayRead(X, &ptr_X));
1309:       PetscCall(VecRestoreArrayRead(XR, &ptr_XR));
1310:       PetscCall(PetscPrintf(comm, "Error ||x-x_e||_1 %g\n", (double)nrm1));
1311:       PetscCall(VecDestroy(&XR));
1312:     }
1313:   }

1315:   PetscCall(SolutionStatsView(da, X, PETSC_VIEWER_STDOUT_WORLD));
1316:   if (draw & 0x1) PetscCall(VecView(X0, PETSC_VIEWER_DRAW_WORLD));
1317:   if (draw & 0x2) PetscCall(VecView(X, PETSC_VIEWER_DRAW_WORLD));
1318:   if (draw & 0x4) {
1319:     Vec Y;
1320:     PetscCall(VecDuplicate(X, &Y));
1321:     PetscCall(FVSample_3WaySplit(&ctx, da, ptime, Y));
1322:     PetscCall(VecAYPX(Y, -1, X));
1323:     PetscCall(VecView(Y, PETSC_VIEWER_DRAW_WORLD));
1324:     PetscCall(VecDestroy(&Y));
1325:   }

1327:   if (view_final) {
1328:     PetscViewer viewer;
1329:     PetscCall(PetscViewerASCIIOpen(PETSC_COMM_WORLD, final_fname, &viewer));
1330:     PetscCall(PetscViewerPushFormat(viewer, PETSC_VIEWER_ASCII_MATLAB));
1331:     PetscCall(VecView(X, viewer));
1332:     PetscCall(PetscViewerPopFormat(viewer));
1333:     PetscCall(PetscViewerDestroy(&viewer));
1334:   }

1336:   /* Clean up */
1337:   PetscCall((*ctx.physics2.destroy)(ctx.physics2.user));
1338:   for (i = 0; i < ctx.physics2.dof; i++) PetscCall(PetscFree(ctx.physics2.fieldname[i]));
1339:   PetscCall(PetscFree4(ctx.R, ctx.Rinv, ctx.cjmpLR, ctx.cslope));
1340:   PetscCall(PetscFree3(ctx.uLR, ctx.flux, ctx.speeds));
1341:   PetscCall(VecDestroy(&X));
1342:   PetscCall(VecDestroy(&X0));
1343:   PetscCall(VecDestroy(&R));
1344:   PetscCall(DMDestroy(&da));
1345:   PetscCall(TSDestroy(&ts));
1346:   PetscCall(ISDestroy(&ctx.iss));
1347:   PetscCall(ISDestroy(&ctx.ism));
1348:   PetscCall(ISDestroy(&ctx.isf));
1349:   PetscCall(ISDestroy(&ctx.issb));
1350:   PetscCall(ISDestroy(&ctx.ismb));
1351:   PetscCall(PetscFree(index_slow));
1352:   PetscCall(PetscFree(index_medium));
1353:   PetscCall(PetscFree(index_fast));
1354:   PetscCall(PetscFree(index_slowbuffer));
1355:   PetscCall(PetscFree(index_mediumbuffer));
1356:   PetscCall(PetscFunctionListDestroy(&limiters));
1357:   PetscCall(PetscFunctionListDestroy(&physics));
1358:   PetscCall(PetscFinalize());
1359:   return 0;
1360: }

1362: /*TEST

1364:     build:
1365:       requires: !complex
1366:       depends: finitevolume1d.c

1368:     test:
1369:       suffix: 1
1370:       args: -da_grid_x 90 -initial 7 -xmin -1 -xmax 1 -hratio 2 -limit mc -ts_time_step 0.025 -ts_max_steps 24 -ts_type mprk -ts_mprk_type 2a23 -ts_use_splitrhsfunction 0

1372:     test:
1373:       suffix: 2
1374:       args: -da_grid_x 90 -initial 7 -xmin -1 -xmax 1 -hratio 2 -limit mc -ts_time_step 0.025 -ts_max_steps 24 -ts_type mprk -ts_mprk_type 2a23 -ts_use_splitrhsfunction 1

1376: TEST*/