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 <petscdraw.h>
 18: #include "finitevolume1d.h"

 20: static inline PetscReal RangeMod(PetscReal a, PetscReal xmin, PetscReal xmax)
 21: {
 22:   PetscReal range = xmax - xmin;
 23:   return xmin + PetscFmodReal(range + PetscFmodReal(a, range), range);
 24: }

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

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

 36:   PetscFunctionBeginUser;
 37:   speed     = ctx->a;
 38:   flux[0]   = PetscMax(0, speed) * uL[0] + PetscMin(0, speed) * uR[0];
 39:   *maxspeed = speed;
 40:   PetscFunctionReturn(PETSC_SUCCESS);
 41: }

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

 47:   PetscFunctionBeginUser;
 48:   X[0]      = 1.;
 49:   Xi[0]     = 1.;
 50:   speeds[0] = ctx->a;
 51:   PetscFunctionReturn(PETSC_SUCCESS);
 52: }

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

 59:   PetscFunctionBeginUser;
 60:   switch (bctype) {
 61:   case FVBC_OUTFLOW:
 62:     x0 = x - a * t;
 63:     break;
 64:   case FVBC_PERIODIC:
 65:     x0 = RangeMod(x - a * t, xmin, xmax);
 66:     break;
 67:   default:
 68:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_UNKNOWN_TYPE, "unknown BCType");
 69:   }
 70:   switch (initial) {
 71:   case 0:
 72:     u[0] = (x0 < 0) ? 1 : -1;
 73:     break;
 74:   case 1:
 75:     u[0] = (x0 < 0) ? -1 : 1;
 76:     break;
 77:   case 2:
 78:     u[0] = (0 < x0 && x0 < 1) ? 1 : 0;
 79:     break;
 80:   case 3:
 81:     u[0] = PetscSinReal(2 * PETSC_PI * x0);
 82:     break;
 83:   case 4:
 84:     u[0] = PetscAbs(x0);
 85:     break;
 86:   case 5:
 87:     u[0] = (x0 < 0 || x0 > 0.5) ? 0 : PetscSqr(PetscSinReal(2 * PETSC_PI * x0));
 88:     break;
 89:   case 6:
 90:     u[0] = (x0 < 0) ? 0 : ((x0 < 1) ? x0 : ((x0 < 2) ? 2 - x0 : 0));
 91:     break;
 92:   case 7:
 93:     u[0] = PetscPowReal(PetscSinReal(PETSC_PI * x0), 10.0);
 94:     break;
 95:   default:
 96:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_UNKNOWN_TYPE, "unknown initial condition");
 97:   }
 98:   PetscFunctionReturn(PETSC_SUCCESS);
 99: }

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

105:   PetscFunctionBeginUser;
106:   PetscCall(PetscNew(&user));
107:   ctx->physics2.sample2         = PhysicsSample_Advect;
108:   ctx->physics2.riemann2        = PhysicsRiemann_Advect;
109:   ctx->physics2.characteristic2 = PhysicsCharacteristic_Advect;
110:   ctx->physics2.destroy         = PhysicsDestroy_SimpleFree;
111:   ctx->physics2.user            = user;
112:   ctx->physics2.dof             = 1;
113:   PetscCall(PetscStrallocpy("u", &ctx->physics2.fieldname[0]));
114:   user->a = 1;
115:   PetscOptionsBegin(ctx->comm, ctx->prefix, "Options for advection", "");
116:   {
117:     PetscCall(PetscOptionsReal("-physics_advect_a", "Speed", "", user->a, &user->a, NULL));
118:   }
119:   PetscOptionsEnd();
120:   PetscFunctionReturn(PETSC_SUCCESS);
121: }

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

130:   PetscFunctionBeginUser;
131:   PetscCheck(ctx->physics2.sample2, PETSC_COMM_SELF, PETSC_ERR_SUP, "Physics has not provided a sampling function");
132:   PetscCall(DMDAGetInfo(da, 0, &Mx, 0, 0, 0, 0, 0, &dof, 0, 0, 0, 0, 0));
133:   PetscCall(DMDAGetCorners(da, &xs, 0, 0, &xm, 0, 0));
134:   PetscCall(DMDAVecGetArray(da, U, &u));
135:   PetscCall(PetscMalloc1(dof, &uj));

137:   hs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
138:   hm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
139:   hf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
140:   for (i = xs; i < xs + xm; i++) {
141:     if (i < ctx->sm) {
142:       xi = ctx->xmin + 0.5 * hs + i * hs;
143:       /* Integrate over cell i using trapezoid rule with N points. */
144:       for (k = 0; k < dof; k++) u[i * dof + k] = 0;
145:       for (j = 0; j < N + 1; j++) {
146:         xj = xi + hs * (j - N / 2) / (PetscReal)N;
147:         PetscCall((*ctx->physics2.sample2)(ctx->physics2.user, ctx->initial, ctx->bctype, ctx->xmin, ctx->xmax, time, xj, uj));
148:         for (k = 0; k < dof; k++) u[i * dof + k] += ((j == 0 || j == N) ? 0.5 : 1.0) * uj[k] / N;
149:       }
150:     } else if (i < ctx->mf) {
151:       xi = ctx->xmin + ctx->sm * hs + 0.5 * hm + (i - ctx->sm) * hm;
152:       /* Integrate over cell i using trapezoid rule with N points. */
153:       for (k = 0; k < dof; k++) u[i * dof + k] = 0;
154:       for (j = 0; j < N + 1; j++) {
155:         xj = xi + hm * (j - N / 2) / (PetscReal)N;
156:         PetscCall((*ctx->physics2.sample2)(ctx->physics2.user, ctx->initial, ctx->bctype, ctx->xmin, ctx->xmax, time, xj, uj));
157:         for (k = 0; k < dof; k++) u[i * dof + k] += ((j == 0 || j == N) ? 0.5 : 1.0) * uj[k] / N;
158:       }
159:     } else if (i < ctx->fm) {
160:       xi = ctx->xmin + ctx->sm * hs + (ctx->mf - ctx->sm) * hm + 0.5 * hf + (i - ctx->mf) * hf;
161:       /* Integrate over cell i using trapezoid rule with N points. */
162:       for (k = 0; k < dof; k++) u[i * dof + k] = 0;
163:       for (j = 0; j < N + 1; j++) {
164:         xj = xi + hf * (j - N / 2) / (PetscReal)N;
165:         PetscCall((*ctx->physics2.sample2)(ctx->physics2.user, ctx->initial, ctx->bctype, ctx->xmin, ctx->xmax, time, xj, uj));
166:         for (k = 0; k < dof; k++) u[i * dof + k] += ((j == 0 || j == N) ? 0.5 : 1.0) * uj[k] / N;
167:       }
168:     } else if (i < ctx->ms) {
169:       xi = ctx->xmin + ctx->sm * hs + (ctx->mf - ctx->sm) * hm + (ctx->fm - ctx->mf) * hf + 0.5 * hm + (i - ctx->fm) * hm;
170:       /* Integrate over cell i using trapezoid rule with N points. */
171:       for (k = 0; k < dof; k++) u[i * dof + k] = 0;
172:       for (j = 0; j < N + 1; j++) {
173:         xj = xi + hm * (j - N / 2) / (PetscReal)N;
174:         PetscCall((*ctx->physics2.sample2)(ctx->physics2.user, ctx->initial, ctx->bctype, ctx->xmin, ctx->xmax, time, xj, uj));
175:         for (k = 0; k < dof; k++) u[i * dof + k] += ((j == 0 || j == N) ? 0.5 : 1.0) * uj[k] / N;
176:       }
177:     } else {
178:       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;
179:       /* Integrate over cell i using trapezoid rule with N points. */
180:       for (k = 0; k < dof; k++) u[i * dof + k] = 0;
181:       for (j = 0; j < N + 1; j++) {
182:         xj = xi + hs * (j - N / 2) / (PetscReal)N;
183:         PetscCall((*ctx->physics2.sample2)(ctx->physics2.user, ctx->initial, ctx->bctype, ctx->xmin, ctx->xmax, time, xj, uj));
184:         for (k = 0; k < dof; k++) u[i * dof + k] += ((j == 0 || j == N) ? 0.5 : 1.0) * uj[k] / N;
185:       }
186:     }
187:   }
188:   PetscCall(DMDAVecRestoreArray(da, U, &u));
189:   PetscCall(PetscFree(uj));
190:   PetscFunctionReturn(PETSC_SUCCESS);
191: }

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

200:   PetscFunctionBeginUser;
201:   PetscCall(VecGetSize(X, &Mx));
202:   hs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
203:   hm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
204:   hf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
205:   PetscCall(VecDuplicate(X, &Y));
206:   PetscCall(FVSample_3WaySplit(ctx, da, t, Y));
207:   PetscCall(VecGetArrayRead(X, &ptr_X));
208:   PetscCall(VecGetArrayRead(Y, &ptr_Y));
209:   for (i = 0; i < Mx; i++) {
210:     if (i < ctx->sm || i > ctx->ms - 1) *nrm1 += hs * PetscAbs(ptr_X[i] - ptr_Y[i]);
211:     else if (i < ctx->mf || i > ctx->fm - 1) *nrm1 += hm * PetscAbs(ptr_X[i] - ptr_Y[i]);
212:     else *nrm1 += hf * PetscAbs(ptr_X[i] - ptr_Y[i]);
213:   }
214:   PetscCall(VecRestoreArrayRead(X, &ptr_X));
215:   PetscCall(VecRestoreArrayRead(Y, &ptr_Y));
216:   PetscCall(VecDestroy(&Y));
217:   PetscFunctionReturn(PETSC_SUCCESS);
218: }

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

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

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

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

246:   PetscCall(DMDAGetCorners(da, &xs, 0, 0, &xm, 0, 0));

248:   if (ctx->bctype == FVBC_OUTFLOW) {
249:     for (i = xs - 2; i < 0; i++) {
250:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
251:     }
252:     for (i = Mx; i < xs + xm + 2; i++) {
253:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
254:     }
255:   }
256:   for (i = xs - 1; i < xs + xm + 1; i++) {
257:     struct _LimitInfo info;
258:     PetscScalar      *cjmpL, *cjmpR;
259:     /* Determine the right eigenvectors R, where A = R \Lambda R^{-1} */
260:     PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
261:     /* Evaluate jumps across interfaces (i-1, i) and (i, i+1), put in characteristic basis */
262:     PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
263:     cjmpL = &ctx->cjmpLR[0];
264:     cjmpR = &ctx->cjmpLR[dof];
265:     for (j = 0; j < dof; j++) {
266:       PetscScalar jmpL, jmpR;
267:       jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
268:       jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
269:       for (k = 0; k < dof; k++) {
270:         cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
271:         cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
272:       }
273:     }
274:     /* Apply limiter to the left and right characteristic jumps */
275:     info.m   = dof;
276:     info.hxs = hxs;
277:     info.hxm = hxm;
278:     info.hxf = hxf;
279:     (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
280:     for (j = 0; j < dof; j++) {
281:       PetscScalar tmp = 0;
282:       for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
283:       slope[i * dof + j] = tmp;
284:     }
285:   }

287:   for (i = xs; i < xs + xm + 1; i++) {
288:     PetscReal    maxspeed;
289:     PetscScalar *uL, *uR;
290:     uL = &ctx->uLR[0];
291:     uR = &ctx->uLR[dof];
292:     if (i < sm || i > ms) { /* slow region */
293:       for (j = 0; j < dof; j++) {
294:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
295:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
296:       }
297:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
298:       if (i > xs) {
299:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxs;
300:       }
301:       if (i < xs + xm) {
302:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxs;
303:       }
304:     } else if (i == sm) { /* interface between slow and medium component */
305:       for (j = 0; j < dof; j++) {
306:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
307:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
308:       }
309:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
310:       if (i > xs) {
311:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxs;
312:       }
313:       if (i < xs + xm) {
314:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxm;
315:       }
316:     } else if (i == ms) { /* interface between medium and slow regions */
317:       for (j = 0; j < dof; j++) {
318:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
319:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
320:       }
321:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
322:       if (i > xs) {
323:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxm;
324:       }
325:       if (i < xs + xm) {
326:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxs;
327:       }
328:     } else if (i < mf || i > fm) { /* medium region */
329:       for (j = 0; j < dof; j++) {
330:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
331:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
332:       }
333:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
334:       if (i > xs) {
335:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxm;
336:       }
337:       if (i < xs + xm) {
338:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxm;
339:       }
340:     } else if (i == mf) { /* interface between medium and fast regions */
341:       for (j = 0; j < dof; j++) {
342:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
343:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxf / 2;
344:       }
345:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
346:       if (i > xs) {
347:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxm;
348:       }
349:       if (i < xs + xm) {
350:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxf;
351:       }
352:     } else if (i == fm) { /* interface between fast and medium regions */
353:       for (j = 0; j < dof; j++) {
354:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxf / 2;
355:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
356:       }
357:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
358:       if (i > xs) {
359:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxf;
360:       }
361:       if (i < xs + xm) {
362:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxm;
363:       }
364:     } else { /* fast region */
365:       for (j = 0; j < dof; j++) {
366:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxf / 2;
367:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxf / 2;
368:       }
369:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
370:       ctx->cfl_idt = PetscMax(ctx->cfl_idt, PetscAbsScalar(maxspeed / hxs)); /* Max allowable value of 1/Delta t */
371:       if (i > xs) {
372:         for (j = 0; j < dof; j++) f[(i - 1) * dof + j] -= ctx->flux[j] / hxf;
373:       }
374:       if (i < xs + xm) {
375:         for (j = 0; j < dof; j++) f[i * dof + j] += ctx->flux[j] / hxf;
376:       }
377:     }
378:   }
379:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
380:   PetscCall(DMDAVecRestoreArray(da, F, &f));
381:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
382:   PetscCall(DMRestoreLocalVector(da, &Xloc));
383:   PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &ctx->cfl_idt, 1, MPIU_SCALAR, MPIU_MAX, PetscObjectComm((PetscObject)da)));
384:   if (0) {
385:     /* We need to a way to inform the TS of a CFL constraint, this is a debugging fragment */
386:     PetscReal dt, tnow;
387:     PetscCall(TSGetTimeStep(ts, &dt));
388:     PetscCall(TSGetTime(ts, &tnow));
389:     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))));
390:   }
391:   PetscFunctionReturn(PETSC_SUCCESS);
392: }

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

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

420:   if (ctx->bctype == FVBC_OUTFLOW) {
421:     for (i = xs - 2; i < 0; i++) {
422:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
423:     }
424:     for (i = Mx; i < xs + xm + 2; i++) {
425:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
426:     }
427:   }
428:   for (i = xs - 1; i < xs + xm + 1; i++) {
429:     struct _LimitInfo info;
430:     PetscScalar      *cjmpL, *cjmpR;
431:     if (i < sm - lsbwidth + 1 || i > ms + rsbwidth - 2) { /* slow components and the first and last fast components */
432:       /* Determine the right eigenvectors R, where A = R \Lambda R^{-1} */
433:       PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
434:       /* Evaluate jumps across interfaces (i-1, i) and (i, i+1), put in characteristic basis */
435:       PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
436:       cjmpL = &ctx->cjmpLR[0];
437:       cjmpR = &ctx->cjmpLR[dof];
438:       for (j = 0; j < dof; j++) {
439:         PetscScalar jmpL, jmpR;
440:         jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
441:         jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
442:         for (k = 0; k < dof; k++) {
443:           cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
444:           cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
445:         }
446:       }
447:       /* Apply limiter to the left and right characteristic jumps */
448:       info.m   = dof;
449:       info.hxs = hxs;
450:       info.hxm = hxm;
451:       info.hxf = hxf;
452:       (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
453:       for (j = 0; j < dof; j++) {
454:         PetscScalar tmp = 0;
455:         for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
456:         slope[i * dof + j] = tmp;
457:       }
458:     }
459:   }

461:   for (i = xs; i < xs + xm + 1; i++) {
462:     PetscReal    maxspeed;
463:     PetscScalar *uL, *uR;
464:     uL = &ctx->uLR[0];
465:     uR = &ctx->uLR[dof];
466:     if (i < sm - lsbwidth) { /* slow region */
467:       for (j = 0; j < dof; j++) {
468:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
469:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
470:       }
471:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
472:       ctx->cfl_idt = PetscMax(ctx->cfl_idt, PetscAbsScalar(maxspeed / hxs)); /* Max allowable value of 1/Delta t */
473:       if (i > xs) {
474:         for (j = 0; j < dof; j++) f[(islow - 1) * dof + j] -= ctx->flux[j] / hxs;
475:       }
476:       if (i < xs + xm) {
477:         for (j = 0; j < dof; j++) f[islow * dof + j] += ctx->flux[j] / hxs;
478:         islow++;
479:       }
480:     }
481:     if (i == sm - lsbwidth) { /* interface between slow and medium regions */
482:       for (j = 0; j < dof; j++) {
483:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
484:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
485:       }
486:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
487:       if (i > xs) {
488:         for (j = 0; j < dof; j++) f[(islow - 1) * dof + j] -= ctx->flux[j] / hxs;
489:       }
490:     }
491:     if (i == ms + rsbwidth) { /* interface between medium and slow regions */
492:       for (j = 0; j < dof; j++) {
493:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
494:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
495:       }
496:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
497:       if (i < xs + xm) {
498:         for (j = 0; j < dof; j++) f[islow * dof + j] += ctx->flux[j] / hxs;
499:         islow++;
500:       }
501:     }
502:     if (i > ms + rsbwidth) { /* slow region */
503:       for (j = 0; j < dof; j++) {
504:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
505:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
506:       }
507:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
508:       ctx->cfl_idt = PetscMax(ctx->cfl_idt, PetscAbsScalar(maxspeed / hxs)); /* Max allowable value of 1/Delta t */
509:       if (i > xs) {
510:         for (j = 0; j < dof; j++) f[(islow - 1) * dof + j] -= ctx->flux[j] / hxs;
511:       }
512:       if (i < xs + xm) {
513:         for (j = 0; j < dof; j++) f[islow * dof + j] += ctx->flux[j] / hxs;
514:         islow++;
515:       }
516:     }
517:   }
518:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
519:   PetscCall(VecRestoreArray(F, &f));
520:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
521:   PetscCall(DMRestoreLocalVector(da, &Xloc));
522:   PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &ctx->cfl_idt, 1, MPIU_SCALAR, MPIU_MAX, PetscObjectComm((PetscObject)da)));
523:   PetscFunctionReturn(PETSC_SUCCESS);
524: }

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

535:   PetscFunctionBeginUser;
536:   PetscCall(TSGetDM(ts, &da));
537:   PetscCall(DMGetLocalVector(da, &Xloc));
538:   PetscCall(DMDAGetInfo(da, 0, &Mx, 0, 0, 0, 0, 0, &dof, 0, 0, 0, 0, 0));
539:   hxs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
540:   hxm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
541:   hxf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
542:   PetscCall(DMGlobalToLocalBegin(da, X, INSERT_VALUES, Xloc));
543:   PetscCall(DMGlobalToLocalEnd(da, X, INSERT_VALUES, Xloc));
544:   PetscCall(VecZeroEntries(F));
545:   PetscCall(DMDAVecGetArray(da, Xloc, &x));
546:   PetscCall(VecGetArray(F, &f));
547:   PetscCall(DMDAGetArray(da, PETSC_TRUE, &slope));
548:   PetscCall(DMDAGetCorners(da, &xs, 0, 0, &xm, 0, 0));

550:   if (ctx->bctype == FVBC_OUTFLOW) {
551:     for (i = xs - 2; i < 0; i++) {
552:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
553:     }
554:     for (i = Mx; i < xs + xm + 2; i++) {
555:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
556:     }
557:   }
558:   for (i = xs - 1; i < xs + xm + 1; i++) {
559:     struct _LimitInfo info;
560:     PetscScalar      *cjmpL, *cjmpR;
561:     if ((i > sm - lsbwidth - 2 && i < sm + 1) || (i > ms - 2 && i < ms + rsbwidth + 1)) {
562:       /* Determine the right eigenvectors R, where A = R \Lambda R^{-1} */
563:       PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
564:       /* Evaluate jumps across interfaces (i-1, i) and (i, i+1), put in characteristic basis */
565:       PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
566:       cjmpL = &ctx->cjmpLR[0];
567:       cjmpR = &ctx->cjmpLR[dof];
568:       for (j = 0; j < dof; j++) {
569:         PetscScalar jmpL, jmpR;
570:         jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
571:         jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
572:         for (k = 0; k < dof; k++) {
573:           cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
574:           cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
575:         }
576:       }
577:       /* Apply limiter to the left and right characteristic jumps */
578:       info.m   = dof;
579:       info.hxs = hxs;
580:       info.hxm = hxm;
581:       info.hxf = hxf;
582:       (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
583:       for (j = 0; j < dof; j++) {
584:         PetscScalar tmp = 0;
585:         for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
586:         slope[i * dof + j] = tmp;
587:       }
588:     }
589:   }

591:   for (i = xs; i < xs + xm + 1; i++) {
592:     PetscReal    maxspeed;
593:     PetscScalar *uL, *uR;
594:     uL = &ctx->uLR[0];
595:     uR = &ctx->uLR[dof];
596:     if (i == sm - lsbwidth) {
597:       for (j = 0; j < dof; j++) {
598:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
599:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
600:       }
601:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
602:       if (i < xs + xm) {
603:         for (j = 0; j < dof; j++) f[islowbuffer * dof + j] += ctx->flux[j] / hxs;
604:         islowbuffer++;
605:       }
606:     }
607:     if (i > sm - lsbwidth && i < sm) {
608:       for (j = 0; j < dof; j++) {
609:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
610:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
611:       }
612:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
613:       if (i > xs) {
614:         for (j = 0; j < dof; j++) f[(islowbuffer - 1) * dof + j] -= ctx->flux[j] / hxs;
615:       }
616:       if (i < xs + xm) {
617:         for (j = 0; j < dof; j++) f[islowbuffer * dof + j] += ctx->flux[j] / hxs;
618:         islowbuffer++;
619:       }
620:     }
621:     if (i == sm) { /* interface between the slow region and the medium region */
622:       for (j = 0; j < dof; j++) {
623:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
624:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
625:       }
626:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
627:       if (i > xs) {
628:         for (j = 0; j < dof; j++) f[(islowbuffer - 1) * dof + j] -= ctx->flux[j] / hxs;
629:       }
630:     }
631:     if (i == ms) { /* interface between the medium region and the slow region */
632:       for (j = 0; j < dof; j++) {
633:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
634:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
635:       }
636:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
637:       if (i < xs + xm) {
638:         for (j = 0; j < dof; j++) f[islowbuffer * dof + j] += ctx->flux[j] / hxs;
639:         islowbuffer++;
640:       }
641:     }
642:     if (i > ms && i < ms + rsbwidth) {
643:       for (j = 0; j < dof; j++) {
644:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
645:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
646:       }
647:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
648:       if (i > xs) {
649:         for (j = 0; j < dof; j++) f[(islowbuffer - 1) * dof + j] -= ctx->flux[j] / hxs;
650:       }
651:       if (i < xs + xm) {
652:         for (j = 0; j < dof; j++) f[islowbuffer * dof + j] += ctx->flux[j] / hxs;
653:         islowbuffer++;
654:       }
655:     }
656:     if (i == ms + rsbwidth) {
657:       for (j = 0; j < dof; j++) {
658:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
659:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
660:       }
661:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
662:       if (i > xs) {
663:         for (j = 0; j < dof; j++) f[(islowbuffer - 1) * dof + j] -= ctx->flux[j] / hxs;
664:       }
665:     }
666:   }
667:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
668:   PetscCall(VecRestoreArray(F, &f));
669:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
670:   PetscCall(DMRestoreLocalVector(da, &Xloc));
671:   PetscFunctionReturn(PETSC_SUCCESS);
672: }

674: /* --------------------------------- Finite Volume Solver for medium components ----------------------------------- */
675: PetscErrorCode FVRHSFunctionmedium_3WaySplit(TS ts, PetscReal time, Vec X, Vec F, void *vctx)
676: {
677:   FVCtx       *ctx = (FVCtx *)vctx;
678:   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;
679:   PetscReal    hxs, hxm, hxf;
680:   PetscScalar *x, *f, *slope;
681:   Vec          Xloc;
682:   DM           da;

684:   PetscFunctionBeginUser;
685:   PetscCall(TSGetDM(ts, &da));
686:   PetscCall(DMGetLocalVector(da, &Xloc));
687:   PetscCall(DMDAGetInfo(da, 0, &Mx, 0, 0, 0, 0, 0, &dof, 0, 0, 0, 0, 0));
688:   hxs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
689:   hxm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
690:   hxf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
691:   PetscCall(DMGlobalToLocalBegin(da, X, INSERT_VALUES, Xloc));
692:   PetscCall(DMGlobalToLocalEnd(da, X, INSERT_VALUES, Xloc));
693:   PetscCall(VecZeroEntries(F));
694:   PetscCall(DMDAVecGetArray(da, Xloc, &x));
695:   PetscCall(VecGetArray(F, &f));
696:   PetscCall(DMDAGetArray(da, PETSC_TRUE, &slope));
697:   PetscCall(DMDAGetCorners(da, &xs, 0, 0, &xm, 0, 0));

699:   if (ctx->bctype == FVBC_OUTFLOW) {
700:     for (i = xs - 2; i < 0; i++) {
701:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
702:     }
703:     for (i = Mx; i < xs + xm + 2; i++) {
704:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
705:     }
706:   }
707:   for (i = xs - 1; i < xs + xm + 1; i++) {
708:     struct _LimitInfo info;
709:     PetscScalar      *cjmpL, *cjmpR;
710:     if ((i > sm - 2 && i < mf - lmbwidth + 1) || (i > fm + rmbwidth - 2 && i < ms + 1)) { /* slow components and the first and last fast components */
711:       /* Determine the right eigenvectors R, where A = R \Lambda R^{-1} */
712:       PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
713:       /* Evaluate jumps across interfaces (i-1, i) and (i, i+1), put in characteristic basis */
714:       PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
715:       cjmpL = &ctx->cjmpLR[0];
716:       cjmpR = &ctx->cjmpLR[dof];
717:       for (j = 0; j < dof; j++) {
718:         PetscScalar jmpL, jmpR;
719:         jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
720:         jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
721:         for (k = 0; k < dof; k++) {
722:           cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
723:           cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
724:         }
725:       }
726:       /* Apply limiter to the left and right characteristic jumps */
727:       info.m   = dof;
728:       info.hxs = hxs;
729:       info.hxm = hxm;
730:       info.hxf = hxf;
731:       (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
732:       for (j = 0; j < dof; j++) {
733:         PetscScalar tmp = 0;
734:         for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
735:         slope[i * dof + j] = tmp;
736:       }
737:     }
738:   }

740:   for (i = xs; i < xs + xm + 1; i++) {
741:     PetscReal    maxspeed;
742:     PetscScalar *uL, *uR;
743:     uL = &ctx->uLR[0];
744:     uR = &ctx->uLR[dof];
745:     if (i == sm) { /* interface between slow and medium regions */
746:       for (j = 0; j < dof; j++) {
747:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxs / 2;
748:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
749:       }
750:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
751:       if (i < xs + xm) {
752:         for (j = 0; j < dof; j++) f[imedium * dof + j] += ctx->flux[j] / hxm;
753:         imedium++;
754:       }
755:     }
756:     if (i > sm && i < mf - lmbwidth) { /* medium region */
757:       for (j = 0; j < dof; j++) {
758:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
759:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
760:       }
761:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
762:       if (i > xs) {
763:         for (j = 0; j < dof; j++) f[(imedium - 1) * dof + j] -= ctx->flux[j] / hxm;
764:       }
765:       if (i < xs + xm) {
766:         for (j = 0; j < dof; j++) f[imedium * dof + j] += ctx->flux[j] / hxm;
767:         imedium++;
768:       }
769:     }
770:     if (i == mf - lmbwidth) { /* interface between medium and fast regions */
771:       for (j = 0; j < dof; j++) {
772:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
773:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
774:       }
775:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
776:       if (i > xs) {
777:         for (j = 0; j < dof; j++) f[(imedium - 1) * dof + j] -= ctx->flux[j] / hxm;
778:       }
779:     }
780:     if (i == fm + rmbwidth) { /* interface between fast and medium regions */
781:       for (j = 0; j < dof; j++) {
782:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
783:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
784:       }
785:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
786:       if (i < xs + xm) {
787:         for (j = 0; j < dof; j++) f[imedium * dof + j] += ctx->flux[j] / hxm;
788:         imedium++;
789:       }
790:     }
791:     if (i > fm + rmbwidth && i < ms) { /* medium region */
792:       for (j = 0; j < dof; j++) {
793:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
794:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
795:       }
796:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
797:       if (i > xs) {
798:         for (j = 0; j < dof; j++) f[(imedium - 1) * dof + j] -= ctx->flux[j] / hxm;
799:       }
800:       if (i < xs + xm) {
801:         for (j = 0; j < dof; j++) f[imedium * dof + j] += ctx->flux[j] / hxm;
802:         imedium++;
803:       }
804:     }
805:     if (i == ms) { /* interface between medium and slow regions */
806:       for (j = 0; j < dof; j++) {
807:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
808:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxs / 2;
809:       }
810:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
811:       if (i > xs) {
812:         for (j = 0; j < dof; j++) f[(imedium - 1) * dof + j] -= ctx->flux[j] / hxm;
813:       }
814:     }
815:   }
816:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
817:   PetscCall(VecRestoreArray(F, &f));
818:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
819:   PetscCall(DMRestoreLocalVector(da, &Xloc));
820:   PetscFunctionReturn(PETSC_SUCCESS);
821: }

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

832:   PetscFunctionBeginUser;
833:   PetscCall(TSGetDM(ts, &da));
834:   PetscCall(DMGetLocalVector(da, &Xloc));
835:   PetscCall(DMDAGetInfo(da, 0, &Mx, 0, 0, 0, 0, 0, &dof, 0, 0, 0, 0, 0));
836:   hxs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
837:   hxm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
838:   hxf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
839:   PetscCall(DMGlobalToLocalBegin(da, X, INSERT_VALUES, Xloc));
840:   PetscCall(DMGlobalToLocalEnd(da, X, INSERT_VALUES, Xloc));
841:   PetscCall(VecZeroEntries(F));
842:   PetscCall(DMDAVecGetArray(da, Xloc, &x));
843:   PetscCall(VecGetArray(F, &f));
844:   PetscCall(DMDAGetArray(da, PETSC_TRUE, &slope));
845:   PetscCall(DMDAGetCorners(da, &xs, 0, 0, &xm, 0, 0));

847:   if (ctx->bctype == FVBC_OUTFLOW) {
848:     for (i = xs - 2; i < 0; i++) {
849:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
850:     }
851:     for (i = Mx; i < xs + xm + 2; i++) {
852:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
853:     }
854:   }
855:   for (i = xs - 1; i < xs + xm + 1; i++) {
856:     struct _LimitInfo info;
857:     PetscScalar      *cjmpL, *cjmpR;
858:     if ((i > mf - lmbwidth - 2 && i < mf + 1) || (i > fm - 2 && i < fm + rmbwidth + 1)) {
859:       /* Determine the right eigenvectors R, where A = R \Lambda R^{-1} */
860:       PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
861:       /* Evaluate jumps across interfaces (i-1, i) and (i, i+1), put in characteristic basis */
862:       PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
863:       cjmpL = &ctx->cjmpLR[0];
864:       cjmpR = &ctx->cjmpLR[dof];
865:       for (j = 0; j < dof; j++) {
866:         PetscScalar jmpL, jmpR;
867:         jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
868:         jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
869:         for (k = 0; k < dof; k++) {
870:           cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
871:           cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
872:         }
873:       }
874:       /* Apply limiter to the left and right characteristic jumps */
875:       info.m   = dof;
876:       info.hxs = hxs;
877:       info.hxm = hxm;
878:       info.hxf = hxf;
879:       (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
880:       for (j = 0; j < dof; j++) {
881:         PetscScalar tmp = 0;
882:         for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
883:         slope[i * dof + j] = tmp;
884:       }
885:     }
886:   }

888:   for (i = xs; i < xs + xm + 1; i++) {
889:     PetscReal    maxspeed;
890:     PetscScalar *uL, *uR;
891:     uL = &ctx->uLR[0];
892:     uR = &ctx->uLR[dof];
893:     if (i == mf - lmbwidth) {
894:       for (j = 0; j < dof; j++) {
895:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
896:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
897:       }
898:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
899:       if (i < xs + xm) {
900:         for (j = 0; j < dof; j++) f[imediumbuffer * dof + j] += ctx->flux[j] / hxm;
901:         imediumbuffer++;
902:       }
903:     }
904:     if (i > mf - lmbwidth && i < mf) {
905:       for (j = 0; j < dof; j++) {
906:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
907:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
908:       }
909:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
910:       if (i > xs) {
911:         for (j = 0; j < dof; j++) f[(imediumbuffer - 1) * dof + j] -= ctx->flux[j] / hxm;
912:       }
913:       if (i < xs + xm) {
914:         for (j = 0; j < dof; j++) f[imediumbuffer * dof + j] += ctx->flux[j] / hxm;
915:         imediumbuffer++;
916:       }
917:     }
918:     if (i == mf) { /* interface between the medium region and the fast region */
919:       for (j = 0; j < dof; j++) {
920:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
921:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxf / 2;
922:       }
923:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
924:       if (i > xs) {
925:         for (j = 0; j < dof; j++) f[(imediumbuffer - 1) * dof + j] -= ctx->flux[j] / hxm;
926:       }
927:     }
928:     if (i == fm) { /* interface between the fast region and the medium region */
929:       for (j = 0; j < dof; j++) {
930:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxf / 2;
931:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
932:       }
933:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
934:       if (i < xs + xm) {
935:         for (j = 0; j < dof; j++) f[imediumbuffer * dof + j] += ctx->flux[j] / hxm;
936:         imediumbuffer++;
937:       }
938:     }
939:     if (i > fm && i < fm + rmbwidth) {
940:       for (j = 0; j < dof; j++) {
941:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
942:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
943:       }
944:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
945:       if (i > xs) {
946:         for (j = 0; j < dof; j++) f[(imediumbuffer - 1) * dof + j] -= ctx->flux[j] / hxm;
947:       }
948:       if (i < xs + xm) {
949:         for (j = 0; j < dof; j++) f[imediumbuffer * dof + j] += ctx->flux[j] / hxm;
950:         imediumbuffer++;
951:       }
952:     }
953:     if (i == fm + rmbwidth) {
954:       for (j = 0; j < dof; j++) {
955:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
956:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
957:       }
958:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
959:       if (i > xs) {
960:         for (j = 0; j < dof; j++) f[(imediumbuffer - 1) * dof + j] -= ctx->flux[j] / hxm;
961:       }
962:     }
963:   }
964:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
965:   PetscCall(VecRestoreArray(F, &f));
966:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
967:   PetscCall(DMRestoreLocalVector(da, &Xloc));
968:   PetscFunctionReturn(PETSC_SUCCESS);
969: }

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

981:   PetscFunctionBeginUser;
982:   PetscCall(TSGetDM(ts, &da));
983:   PetscCall(DMGetLocalVector(da, &Xloc));
984:   PetscCall(DMDAGetInfo(da, 0, &Mx, 0, 0, 0, 0, 0, &dof, 0, 0, 0, 0, 0));
985:   hxs = (ctx->xmax - ctx->xmin) / 8.0 / ctx->sm;
986:   hxm = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->mf - ctx->sm);
987:   hxf = (ctx->xmax - ctx->xmin) / 4.0 / (ctx->fm - ctx->mf);
988:   PetscCall(DMGlobalToLocalBegin(da, X, INSERT_VALUES, Xloc));
989:   PetscCall(DMGlobalToLocalEnd(da, X, INSERT_VALUES, Xloc));
990:   PetscCall(VecZeroEntries(F));
991:   PetscCall(DMDAVecGetArray(da, Xloc, &x));
992:   PetscCall(VecGetArray(F, &f));
993:   PetscCall(DMDAGetArray(da, PETSC_TRUE, &slope));
994:   PetscCall(DMDAGetCorners(da, &xs, 0, 0, &xm, 0, 0));

996:   if (ctx->bctype == FVBC_OUTFLOW) {
997:     for (i = xs - 2; i < 0; i++) {
998:       for (j = 0; j < dof; j++) x[i * dof + j] = x[j];
999:     }
1000:     for (i = Mx; i < xs + xm + 2; i++) {
1001:       for (j = 0; j < dof; j++) x[i * dof + j] = x[(xs + xm - 1) * dof + j];
1002:     }
1003:   }
1004:   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 */
1005:     struct _LimitInfo info;
1006:     PetscScalar      *cjmpL, *cjmpR;
1007:     if (i > mf - 2 && i < fm + 1) {
1008:       PetscCall((*ctx->physics2.characteristic2)(ctx->physics2.user, dof, &x[i * dof], ctx->R, ctx->Rinv, ctx->speeds));
1009:       PetscCall(PetscArrayzero(ctx->cjmpLR, 2 * dof));
1010:       cjmpL = &ctx->cjmpLR[0];
1011:       cjmpR = &ctx->cjmpLR[dof];
1012:       for (j = 0; j < dof; j++) {
1013:         PetscScalar jmpL, jmpR;
1014:         jmpL = x[(i + 0) * dof + j] - x[(i - 1) * dof + j];
1015:         jmpR = x[(i + 1) * dof + j] - x[(i + 0) * dof + j];
1016:         for (k = 0; k < dof; k++) {
1017:           cjmpL[k] += ctx->Rinv[k + j * dof] * jmpL;
1018:           cjmpR[k] += ctx->Rinv[k + j * dof] * jmpR;
1019:         }
1020:       }
1021:       /* Apply limiter to the left and right characteristic jumps */
1022:       info.m   = dof;
1023:       info.hxs = hxs;
1024:       info.hxm = hxm;
1025:       info.hxf = hxf;
1026:       (*ctx->limit3)(&info, cjmpL, cjmpR, ctx->sm, ctx->mf, ctx->fm, ctx->ms, i, ctx->cslope);
1027:       for (j = 0; j < dof; j++) {
1028:         PetscScalar tmp = 0;
1029:         for (k = 0; k < dof; k++) tmp += ctx->R[j + k * dof] * ctx->cslope[k];
1030:         slope[i * dof + j] = tmp;
1031:       }
1032:     }
1033:   }

1035:   for (i = xs; i < xs + xm + 1; i++) {
1036:     PetscReal    maxspeed;
1037:     PetscScalar *uL, *uR;
1038:     uL = &ctx->uLR[0];
1039:     uR = &ctx->uLR[dof];
1040:     if (i == mf) { /* interface between medium and fast regions */
1041:       for (j = 0; j < dof; j++) {
1042:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxm / 2;
1043:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxf / 2;
1044:       }
1045:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
1046:       if (i < xs + xm) {
1047:         for (j = 0; j < dof; j++) f[ifast * dof + j] += ctx->flux[j] / hxf;
1048:         ifast++;
1049:       }
1050:     }
1051:     if (i > mf && i < fm) { /* fast region */
1052:       for (j = 0; j < dof; j++) {
1053:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxf / 2;
1054:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxf / 2;
1055:       }
1056:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
1057:       if (i > xs) {
1058:         for (j = 0; j < dof; j++) f[(ifast - 1) * dof + j] -= ctx->flux[j] / hxf;
1059:       }
1060:       if (i < xs + xm) {
1061:         for (j = 0; j < dof; j++) f[ifast * dof + j] += ctx->flux[j] / hxf;
1062:         ifast++;
1063:       }
1064:     }
1065:     if (i == fm) { /* interface between fast and medium regions */
1066:       for (j = 0; j < dof; j++) {
1067:         uL[j] = x[(i - 1) * dof + j] + slope[(i - 1) * dof + j] * hxf / 2;
1068:         uR[j] = x[(i - 0) * dof + j] - slope[(i - 0) * dof + j] * hxm / 2;
1069:       }
1070:       PetscCall((*ctx->physics2.riemann2)(ctx->physics2.user, dof, uL, uR, ctx->flux, &maxspeed));
1071:       if (i > xs) {
1072:         for (j = 0; j < dof; j++) f[(ifast - 1) * dof + j] -= ctx->flux[j] / hxf;
1073:       }
1074:     }
1075:   }
1076:   PetscCall(DMDAVecRestoreArray(da, Xloc, &x));
1077:   PetscCall(VecRestoreArray(F, &f));
1078:   PetscCall(DMDARestoreArray(da, PETSC_TRUE, &slope));
1079:   PetscCall(DMRestoreLocalVector(da, &Xloc));
1080:   PetscFunctionReturn(PETSC_SUCCESS);
1081: }

1083: int main(int argc, char *argv[])
1084: {
1085:   char              lname[256] = "mc", physname[256] = "advect", final_fname[256] = "solution.m";
1086:   PetscFunctionList limiters = 0, physics = 0;
1087:   MPI_Comm          comm;
1088:   TS                ts;
1089:   DM                da;
1090:   Vec               X, X0, R;
1091:   FVCtx             ctx;
1092:   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;
1093:   PetscBool         view_final = PETSC_FALSE;
1094:   PetscReal         ptime;

1096:   PetscFunctionBeginUser;
1097:   PetscCall(PetscInitialize(&argc, &argv, 0, help));
1098:   comm = PETSC_COMM_WORLD;
1099:   PetscCall(PetscMemzero(&ctx, sizeof(ctx)));

1101:   /* Register limiters to be available on the command line */
1102:   PetscCall(PetscFunctionListAdd(&limiters, "upwind", Limit3_Upwind));
1103:   PetscCall(PetscFunctionListAdd(&limiters, "lax-wendroff", Limit3_LaxWendroff));
1104:   PetscCall(PetscFunctionListAdd(&limiters, "beam-warming", Limit3_BeamWarming));
1105:   PetscCall(PetscFunctionListAdd(&limiters, "fromm", Limit3_Fromm));
1106:   PetscCall(PetscFunctionListAdd(&limiters, "minmod", Limit3_Minmod));
1107:   PetscCall(PetscFunctionListAdd(&limiters, "superbee", Limit3_Superbee));
1108:   PetscCall(PetscFunctionListAdd(&limiters, "mc", Limit3_MC));
1109:   PetscCall(PetscFunctionListAdd(&limiters, "koren3", Limit3_Koren3));

1111:   /* Register physical models to be available on the command line */
1112:   PetscCall(PetscFunctionListAdd(&physics, "advect", PhysicsCreate_Advect));

1114:   ctx.comm   = comm;
1115:   ctx.cfl    = 0.9;
1116:   ctx.bctype = FVBC_PERIODIC;
1117:   ctx.xmin   = -1.0;
1118:   ctx.xmax   = 1.0;
1119:   PetscOptionsBegin(comm, NULL, "Finite Volume solver options", "");
1120:   PetscCall(PetscOptionsReal("-xmin", "X min", "", ctx.xmin, &ctx.xmin, NULL));
1121:   PetscCall(PetscOptionsReal("-xmax", "X max", "", ctx.xmax, &ctx.xmax, NULL));
1122:   PetscCall(PetscOptionsFList("-limit", "Name of flux imiter to use", "", limiters, lname, lname, sizeof(lname), NULL));
1123:   PetscCall(PetscOptionsInt("-draw", "Draw solution vector, bitwise OR of (1=initial,2=final,4=final error)", "", draw, &draw, NULL));
1124:   PetscCall(PetscOptionsString("-view_final", "Write final solution in ASCII MATLAB format to given file name", "", final_fname, final_fname, sizeof(final_fname), &view_final));
1125:   PetscCall(PetscOptionsInt("-initial", "Initial condition (depends on the physics)", "", ctx.initial, &ctx.initial, NULL));
1126:   PetscCall(PetscOptionsBool("-exact", "Compare errors with exact solution", "", ctx.exact, &ctx.exact, NULL));
1127:   PetscCall(PetscOptionsBool("-simulation", "Compare errors with reference solution", "", ctx.simulation, &ctx.simulation, NULL));
1128:   PetscCall(PetscOptionsReal("-cfl", "CFL number to time step at", "", ctx.cfl, &ctx.cfl, NULL));
1129:   PetscCall(PetscOptionsEnum("-bc_type", "Boundary condition", "", FVBCTypes, (PetscEnum)ctx.bctype, (PetscEnum *)&ctx.bctype, NULL));
1130:   PetscCall(PetscOptionsInt("-hratio", "Spacing ratio", "", ctx.hratio, &ctx.hratio, NULL));
1131:   PetscOptionsEnd();

1133:   /* Choose the limiter from the list of registered limiters */
1134:   PetscCall(PetscFunctionListFind(limiters, lname, &ctx.limit3));
1135:   PetscCheck(ctx.limit3, PETSC_COMM_SELF, PETSC_ERR_ARG_UNKNOWN_TYPE, "Limiter '%s' not found", lname);

1137:   /* Choose the physics from the list of registered models */
1138:   {
1139:     PetscErrorCode (*r)(FVCtx *);
1140:     PetscCall(PetscFunctionListFind(physics, physname, &r));
1141:     PetscCheck(r, PETSC_COMM_SELF, PETSC_ERR_ARG_UNKNOWN_TYPE, "Physics '%s' not found", physname);
1142:     /* Create the physics, will set the number of fields and their names */
1143:     PetscCall((*r)(&ctx));
1144:   }

1146:   /* Create a DMDA to manage the parallel grid */
1147:   PetscCall(DMDACreate1d(comm, DM_BOUNDARY_PERIODIC, 50, ctx.physics2.dof, 2, NULL, &da));
1148:   PetscCall(DMSetFromOptions(da));
1149:   PetscCall(DMSetUp(da));
1150:   /* Inform the DMDA of the field names provided by the physics. */
1151:   /* The names will be shown in the title bars when run with -ts_monitor_draw_solution */
1152:   for (i = 0; i < ctx.physics2.dof; i++) PetscCall(DMDASetFieldName(da, i, ctx.physics2.fieldname[i]));
1153:   PetscCall(DMDAGetInfo(da, 0, &Mx, 0, 0, 0, 0, 0, &dof, 0, 0, 0, 0, 0));
1154:   PetscCall(DMDAGetCorners(da, &xs, 0, 0, &xm, 0, 0));

1156:   /* Set coordinates of cell centers */
1157:   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));

1159:   /* Allocate work space for the Finite Volume solver (so it doesn't have to be reallocated on each function evaluation) */
1160:   PetscCall(PetscMalloc4(dof * dof, &ctx.R, dof * dof, &ctx.Rinv, 2 * dof, &ctx.cjmpLR, 1 * dof, &ctx.cslope));
1161:   PetscCall(PetscMalloc3(2 * dof, &ctx.uLR, dof, &ctx.flux, dof, &ctx.speeds));

1163:   /* Create a vector to store the solution and to save the initial state */
1164:   PetscCall(DMCreateGlobalVector(da, &X));
1165:   PetscCall(VecDuplicate(X, &X0));
1166:   PetscCall(VecDuplicate(X, &R));

1168:   /* create index for slow parts and fast parts,
1169:      count_slow + count_fast = Mx, counts_slow*hs = 0.5, counts_fast*hf = 0.5 */
1170:   count_slow   = Mx / (1 + ctx.hratio) / (1 + ctx.hratio);
1171:   count_medium = 2 * ctx.hratio * count_slow;
1172:   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");
1173:   count_fast = ctx.hratio * ctx.hratio * count_slow;
1174:   ctx.sm     = count_slow / 2;
1175:   ctx.mf     = ctx.sm + count_medium / 2;
1176:   ctx.fm     = ctx.mf + count_fast;
1177:   ctx.ms     = ctx.fm + count_medium / 2;
1178:   PetscCall(PetscMalloc1(xm * dof, &index_slow));
1179:   PetscCall(PetscMalloc1(xm * dof, &index_medium));
1180:   PetscCall(PetscMalloc1(xm * dof, &index_fast));
1181:   PetscCall(PetscMalloc1(6 * dof, &index_slowbuffer));
1182:   PetscCall(PetscMalloc1(6 * dof, &index_mediumbuffer));
1183:   if (((AdvectCtx *)ctx.physics2.user)->a > 0) {
1184:     ctx.lsbwidth = 2;
1185:     ctx.rsbwidth = 4;
1186:     ctx.lmbwidth = 2;
1187:     ctx.rmbwidth = 4;
1188:   } else {
1189:     ctx.lsbwidth = 4;
1190:     ctx.rsbwidth = 2;
1191:     ctx.lmbwidth = 4;
1192:     ctx.rmbwidth = 2;
1193:   }

1195:   for (i = xs; i < xs + xm; i++) {
1196:     if (i < ctx.sm - ctx.lsbwidth || i > ctx.ms + ctx.rsbwidth - 1)
1197:       for (k = 0; k < dof; k++) index_slow[islow++] = i * dof + k;
1198:     else if ((i >= ctx.sm - ctx.lsbwidth && i < ctx.sm) || (i > ctx.ms - 1 && i <= ctx.ms + ctx.rsbwidth - 1))
1199:       for (k = 0; k < dof; k++) index_slowbuffer[islowbuffer++] = i * dof + k;
1200:     else if (i < ctx.mf - ctx.lmbwidth || i > ctx.fm + ctx.rmbwidth - 1)
1201:       for (k = 0; k < dof; k++) index_medium[imedium++] = i * dof + k;
1202:     else if ((i >= ctx.mf - ctx.lmbwidth && i < ctx.mf) || (i > ctx.fm - 1 && i <= ctx.fm + ctx.rmbwidth - 1))
1203:       for (k = 0; k < dof; k++) index_mediumbuffer[imediumbuffer++] = i * dof + k;
1204:     else
1205:       for (k = 0; k < dof; k++) index_fast[ifast++] = i * dof + k;
1206:   }
1207:   PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, islow, index_slow, PETSC_COPY_VALUES, &ctx.iss));
1208:   PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, imedium, index_medium, PETSC_COPY_VALUES, &ctx.ism));
1209:   PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, ifast, index_fast, PETSC_COPY_VALUES, &ctx.isf));
1210:   PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, islowbuffer, index_slowbuffer, PETSC_COPY_VALUES, &ctx.issb));
1211:   PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, imediumbuffer, index_mediumbuffer, PETSC_COPY_VALUES, &ctx.ismb));

1213:   /* Create a time-stepping object */
1214:   PetscCall(TSCreate(comm, &ts));
1215:   PetscCall(TSSetDM(ts, da));
1216:   PetscCall(TSSetRHSFunction(ts, R, FVRHSFunction_3WaySplit, &ctx));
1217:   PetscCall(TSRHSSplitSetIS(ts, "slow", ctx.iss));
1218:   PetscCall(TSRHSSplitSetIS(ts, "medium", ctx.ism));
1219:   PetscCall(TSRHSSplitSetIS(ts, "fast", ctx.isf));
1220:   PetscCall(TSRHSSplitSetIS(ts, "slowbuffer", ctx.issb));
1221:   PetscCall(TSRHSSplitSetIS(ts, "mediumbuffer", ctx.ismb));
1222:   PetscCall(TSRHSSplitSetRHSFunction(ts, "slow", NULL, FVRHSFunctionslow_3WaySplit, &ctx));
1223:   PetscCall(TSRHSSplitSetRHSFunction(ts, "medium", NULL, FVRHSFunctionmedium_3WaySplit, &ctx));
1224:   PetscCall(TSRHSSplitSetRHSFunction(ts, "fast", NULL, FVRHSFunctionfast_3WaySplit, &ctx));
1225:   PetscCall(TSRHSSplitSetRHSFunction(ts, "slowbuffer", NULL, FVRHSFunctionslowbuffer_3WaySplit, &ctx));
1226:   PetscCall(TSRHSSplitSetRHSFunction(ts, "mediumbuffer", NULL, FVRHSFunctionmediumbuffer_3WaySplit, &ctx));

1228:   PetscCall(TSSetType(ts, TSSSP));
1229:   /*PetscCall(TSSetType(ts,TSMPRK));*/
1230:   PetscCall(TSSetMaxTime(ts, 10));
1231:   PetscCall(TSSetExactFinalTime(ts, TS_EXACTFINALTIME_STEPOVER));

1233:   /* Compute initial conditions and starting time step */
1234:   PetscCall(FVSample_3WaySplit(&ctx, da, 0, X0));
1235:   PetscCall(FVRHSFunction_3WaySplit(ts, 0, X0, X, (void *)&ctx)); /* Initial function evaluation, only used to determine max speed */
1236:   PetscCall(VecCopy(X0, X));                                      /* The function value was not used so we set X=X0 again */
1237:   PetscCall(TSSetTimeStep(ts, ctx.cfl / ctx.cfl_idt));
1238:   PetscCall(TSSetFromOptions(ts)); /* Take runtime options */
1239:   PetscCall(SolutionStatsView(da, X, PETSC_VIEWER_STDOUT_WORLD));
1240:   {
1241:     PetscInt           steps;
1242:     PetscScalar        mass_initial, mass_final, mass_difference;
1243:     const PetscScalar *ptr_X, *ptr_X0;
1244:     const PetscReal    hs = (ctx.xmax - ctx.xmin) / 4.0 / count_slow;
1245:     const PetscReal    hm = (ctx.xmax - ctx.xmin) / 2.0 / count_medium;
1246:     const PetscReal    hf = (ctx.xmax - ctx.xmin) / 4.0 / count_fast;

1248:     PetscCall(TSSolve(ts, X));
1249:     PetscCall(TSGetSolveTime(ts, &ptime));
1250:     PetscCall(TSGetStepNumber(ts, &steps));
1251:     /* calculate the total mass at initial time and final time */
1252:     mass_initial = 0.0;
1253:     mass_final   = 0.0;
1254:     PetscCall(DMDAVecGetArrayRead(da, X0, (void *)&ptr_X0));
1255:     PetscCall(DMDAVecGetArrayRead(da, X, (void *)&ptr_X));
1256:     for (i = xs; i < xs + xm; i++) {
1257:       if (i < ctx.sm || i > ctx.ms - 1)
1258:         for (k = 0; k < dof; k++) {
1259:           mass_initial = mass_initial + hs * ptr_X0[i * dof + k];
1260:           mass_final   = mass_final + hs * ptr_X[i * dof + k];
1261:         }
1262:       else if (i < ctx.mf || i > ctx.fm - 1)
1263:         for (k = 0; k < dof; k++) {
1264:           mass_initial = mass_initial + hm * ptr_X0[i * dof + k];
1265:           mass_final   = mass_final + hm * ptr_X[i * dof + k];
1266:         }
1267:       else {
1268:         for (k = 0; k < dof; k++) {
1269:           mass_initial = mass_initial + hf * ptr_X0[i * dof + k];
1270:           mass_final   = mass_final + hf * ptr_X[i * dof + k];
1271:         }
1272:       }
1273:     }
1274:     PetscCall(DMDAVecRestoreArrayRead(da, X0, (void *)&ptr_X0));
1275:     PetscCall(DMDAVecRestoreArrayRead(da, X, (void *)&ptr_X));
1276:     mass_difference = mass_final - mass_initial;
1277:     PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &mass_difference, 1, MPIU_SCALAR, MPIU_SUM, comm));
1278:     PetscCall(PetscPrintf(comm, "Mass difference %g\n", (double)mass_difference));
1279:     PetscCall(PetscPrintf(comm, "Final time %g, steps %" PetscInt_FMT "\n", (double)ptime, steps));
1280:     PetscCall(PetscPrintf(comm, "Maximum allowable stepsize according to CFL %g\n", (double)(1 / ctx.cfl_idt)));
1281:     if (ctx.exact) {
1282:       PetscReal nrm1 = 0;
1283:       PetscCall(SolutionErrorNorms_3WaySplit(&ctx, da, ptime, X, &nrm1));
1284:       PetscCall(PetscPrintf(comm, "Error ||x-x_e||_1 %g\n", (double)nrm1));
1285:     }
1286:     if (ctx.simulation) {
1287:       PetscReal          nrm1 = 0;
1288:       PetscViewer        fd;
1289:       char               filename[PETSC_MAX_PATH_LEN] = "binaryoutput";
1290:       Vec                XR;
1291:       PetscBool          flg;
1292:       const PetscScalar *ptr_XR;
1293:       PetscCall(PetscOptionsGetString(NULL, NULL, "-f", filename, sizeof(filename), &flg));
1294:       PetscCheck(flg, PETSC_COMM_WORLD, PETSC_ERR_USER, "Must indicate binary file with the -f option");
1295:       PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, filename, FILE_MODE_READ, &fd));
1296:       PetscCall(VecDuplicate(X0, &XR));
1297:       PetscCall(VecLoad(XR, fd));
1298:       PetscCall(PetscViewerDestroy(&fd));
1299:       PetscCall(VecGetArrayRead(X, &ptr_X));
1300:       PetscCall(VecGetArrayRead(XR, &ptr_XR));
1301:       for (i = xs; i < xs + xm; i++) {
1302:         if (i < ctx.sm || i > ctx.ms - 1)
1303:           for (k = 0; k < dof; k++) nrm1 = nrm1 + hs * PetscAbs(ptr_X[i * dof + k] - ptr_XR[i * dof + k]);
1304:         else if (i < ctx.mf || i < ctx.fm - 1)
1305:           for (k = 0; k < dof; k++) nrm1 = nrm1 + hm * PetscAbs(ptr_X[i * dof + k] - ptr_XR[i * dof + k]);
1306:         else
1307:           for (k = 0; k < dof; k++) nrm1 = nrm1 + hf * PetscAbs(ptr_X[i * dof + k] - ptr_XR[i * dof + k]);
1308:       }
1309:       PetscCall(VecRestoreArrayRead(X, &ptr_X));
1310:       PetscCall(VecRestoreArrayRead(XR, &ptr_XR));
1311:       PetscCall(PetscPrintf(comm, "Error ||x-x_e||_1 %g\n", (double)nrm1));
1312:       PetscCall(VecDestroy(&XR));
1313:     }
1314:   }

1316:   PetscCall(SolutionStatsView(da, X, PETSC_VIEWER_STDOUT_WORLD));
1317:   if (draw & 0x1) PetscCall(VecView(X0, PETSC_VIEWER_DRAW_WORLD));
1318:   if (draw & 0x2) PetscCall(VecView(X, PETSC_VIEWER_DRAW_WORLD));
1319:   if (draw & 0x4) {
1320:     Vec Y;
1321:     PetscCall(VecDuplicate(X, &Y));
1322:     PetscCall(FVSample_3WaySplit(&ctx, da, ptime, Y));
1323:     PetscCall(VecAYPX(Y, -1, X));
1324:     PetscCall(VecView(Y, PETSC_VIEWER_DRAW_WORLD));
1325:     PetscCall(VecDestroy(&Y));
1326:   }

1328:   if (view_final) {
1329:     PetscViewer viewer;
1330:     PetscCall(PetscViewerASCIIOpen(PETSC_COMM_WORLD, final_fname, &viewer));
1331:     PetscCall(PetscViewerPushFormat(viewer, PETSC_VIEWER_ASCII_MATLAB));
1332:     PetscCall(VecView(X, viewer));
1333:     PetscCall(PetscViewerPopFormat(viewer));
1334:     PetscCall(PetscViewerDestroy(&viewer));
1335:   }

1337:   /* Clean up */
1338:   PetscCall((*ctx.physics2.destroy)(ctx.physics2.user));
1339:   for (i = 0; i < ctx.physics2.dof; i++) PetscCall(PetscFree(ctx.physics2.fieldname[i]));
1340:   PetscCall(PetscFree4(ctx.R, ctx.Rinv, ctx.cjmpLR, ctx.cslope));
1341:   PetscCall(PetscFree3(ctx.uLR, ctx.flux, ctx.speeds));
1342:   PetscCall(VecDestroy(&X));
1343:   PetscCall(VecDestroy(&X0));
1344:   PetscCall(VecDestroy(&R));
1345:   PetscCall(DMDestroy(&da));
1346:   PetscCall(TSDestroy(&ts));
1347:   PetscCall(ISDestroy(&ctx.iss));
1348:   PetscCall(ISDestroy(&ctx.ism));
1349:   PetscCall(ISDestroy(&ctx.isf));
1350:   PetscCall(ISDestroy(&ctx.issb));
1351:   PetscCall(ISDestroy(&ctx.ismb));
1352:   PetscCall(PetscFree(index_slow));
1353:   PetscCall(PetscFree(index_medium));
1354:   PetscCall(PetscFree(index_fast));
1355:   PetscCall(PetscFree(index_slowbuffer));
1356:   PetscCall(PetscFree(index_mediumbuffer));
1357:   PetscCall(PetscFunctionListDestroy(&limiters));
1358:   PetscCall(PetscFunctionListDestroy(&physics));
1359:   PetscCall(PetscFinalize());
1360:   return 0;
1361: }

1363: /*TEST

1365:     build:
1366:       requires: !complex
1367:       depends: finitevolume1d.c

1369:     test:
1370:       suffix: 1
1371:       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

1373:     test:
1374:       suffix: 2
1375:       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

1377: TEST*/