Actual source code: ex30.c

  1: static char help[] =
  2: "ex30: Steady-state 2D subduction flow, pressure and temperature solver.\n\
  3:        The flow is driven by the subducting slab.\n\
  4: ---------------------------------ex30 help---------------------------------\n\
  5:   -OPTION <DEFAULT> = (UNITS) DESCRIPTION.\n\n\
  6:   -width <320> = (km) width of domain.\n\
  7:   -depth <300> = (km) depth of domain.\n\
  8:   -slab_dip <45> = (degrees) dip angle of the slab (determines the grid aspect ratio).\n\
  9:   -lid_depth <35> = (km) depth of the static conductive lid.\n\
 10:   -fault_depth <35> = (km) depth of slab-wedge mechanical coupling\n\
 11:      ( fault dept >= lid depth ).\n\
 12: \n\
 13:   -ni <82> = grid cells in x-direction. (nj adjusts to accommodate\n\
 14:       the slab dip & depth). DO NOT USE -da_grid_x option!!!\n\
 15:   -ivisc <3> = rheology option.\n\
 16:       0 --- constant viscosity.\n\
 17:       1 --- olivine diffusion creep rheology (T&P-dependent, newtonian).\n\
 18:       2 --- olivine dislocation creep rheology (T&P-dependent, non-newtonian).\n\
 19:       3 --- Full mantle rheology, combination of 1 & 2.\n\
 20: \n\
 21:   -slab_velocity <5> = (cm/year) convergence rate of slab into subduction zone.\n\
 22:   -slab_age <50> = (million yrs) age of slab for thermal profile boundary condition.\n\
 23:   -lid_age <50> = (million yrs) age of lid for thermal profile boundary condition.\n\
 24: \n\
 25:   FOR OTHER PARAMETER OPTIONS AND THEIR DEFAULT VALUES, see SetParams() in ex30.c.\n\
 26: ---------------------------------ex30 help---------------------------------\n";


 29: /* ------------------------------------------------------------------------
 30:    
 31:     This PETSc 2.2.0 example by Richard F. Katz
 32:     http://www.ldeo.columbia.edu/~katz/

 34:     The problem is modeled by the partial differential equation system
 35:   
 36:        (1)   -Grad(P) + Div[Eta (Grad(v) + Grad(v)^T)] = 0
 37:        (2)                                    Div(U,W) = 0
 38:        (3)             dT/dt + Div(vT) - 1/Pe Del^2(T) = 0
 39:        (4)   Eta(T,Eps_dot) = constant                             if ivisc==0
 40:                             = diffusion creep (T,P-dependent)      if ivisc==1
 41:                             = dislocation creep (T,P,v-dependent)  if ivisc==2
 42:                                   = mantle viscosity (difn & disl)       if ivisc==3

 44:     which is uniformly discretized on a staggered mesh:
 45:                       -------w_ij------
 46:                       |               |
 47:                   u_i-1j    P,T_ij   u_ij
 48:                       |               |
 49:                        ------w_ij-1-----

 51:   ------------------------------------------------------------------------- */

 53:  #include petscsnes.h
 54:  #include petscda.h
 55:  #include petscdmmg.h

 57: #define VISC_CONST   0
 58: #define VISC_DIFN    1
 59: #define VISC_DISL    2
 60: #define VISC_FULL    3
 61: #define CELL_CENTER  0
 62: #define CELL_CORNER  1
 63: #define BC_ANALYTIC  0
 64: #define BC_NOSTRESS  1
 65: #define BC_EXPERMNT  2
 66: #define ADVECT_FV    0
 67: #define ADVECT_FROMM 1
 68: #define PLATE_SLAB   0
 69: #define PLATE_LID    1
 70: #define EPS_ZERO     0.00000001

 72: typedef struct { /* holds the variables to be solved for */
 73:   PetscScalar u,w,p,T;
 74: } Field;

 76: typedef struct { /* parameters needed to compute viscosity */
 77:   PetscReal    A,n,Estar,Vstar;
 78: } ViscParam;

 80: typedef struct { /* physical and miscelaneous parameters */
 81:   PetscReal    width, depth, scaled_width, scaled_depth, peclet, potentialT;
 82:   PetscReal    slab_dip, slab_age, slab_velocity, kappa, z_scale;
 83:   PetscReal    c, d, sb, cb, skt, visc_cutoff, lid_age, eta0, continuation;
 84:   PetscReal    L, V, lid_depth, fault_depth;
 85:   ViscParam    diffusion, dislocation;
 86:   PetscInt     ivisc, adv_scheme, ibound, output_ivisc;
 87:   PetscTruth   quiet, param_test, output_to_file, pv_analytic;
 88:   PetscTruth   interrupted, stop_solve, toggle_kspmon, kspmon;
 89:   char         filename[PETSC_MAX_PATH_LEN];
 90: } Parameter;

 92: typedef struct { /* grid parameters */
 93:   DAPeriodicType periodic;
 94:   DAStencilType  stencil;
 95:   PetscInt       corner,ni,nj,jlid,jfault,inose;
 96:   PetscInt       dof,stencil_width,mglevels;
 97:   PassiveScalar  dx,dz;
 98: } GridInfo;

100: typedef struct { /* application context */
101:   Vec          Xguess;
102:   Parameter    *param;
103:   GridInfo     *grid;
104: } AppCtx;

106: /* Callback functions (static interface) */

110: /* Main routines */

117: /* Physics subroutines */

128: /* Utilities for interpolation, ICs and BCs */

139: /* Post-processing & misc */

146: /*-----------------------------------------------------------------------*/
149: int main(int argc,char **argv)
150: /*-----------------------------------------------------------------------*/
151: {
152:   DMMG           *dmmg;               /* multilevel grid structure */
153:   AppCtx         *user;               /* user-defined work context */
154:   Parameter      param;
155:   GridInfo       grid;
156:   PetscInt       nits;
158:   MPI_Comm       comm;
159:   DA             da;

161:   PetscInitialize(&argc,&argv,(char *)0,help);
162:   PetscOptionsSetValue("-file","ex30_output");
163:   PetscOptionsSetValue("-snes_monitor",PETSC_NULL);
164:   PetscOptionsSetValue("-snes_max_it","20");
165:   PetscOptionsSetValue("-ksp_max_it","1500");
166:   PetscOptionsSetValue("-ksp_gmres_restart","300");
167:   PetscOptionsInsert(&argc,&argv,PETSC_NULL);

169:   comm = PETSC_COMM_WORLD;

171:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
172:      Set up the problem parameters.
173:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
174:   SetParams(&param,&grid);
175:   ReportParams(&param,&grid);

177: #if 0
178:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
179:      Create user context, set problem data, create vector data structures.
180:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
181:   PetscMalloc(sizeof(AppCtx),&user);
182:   user->param = &param;
183:   user->grid  = &grid;

185:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
186:      Create distributed array multigrid object (DMMG) to manage parallel grid and vectors
187:      for principal unknowns (x) and governing residuals (f)
188:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
189:   DMMGCreate(comm,grid.mglevels,user,&dmmg);
190:   DACreate2d(comm,grid.periodic,grid.stencil,grid.ni,grid.nj,PETSC_DECIDE,PETSC_DECIDE,grid.dof,grid.stencil_width,0,0,&da);
191:   DMMGSetDM(dmmg,(DM)da);
192:   DADestroy(da);
193:   DASetFieldName(DMMGGetDA(dmmg),0,"x-velocity");
194:   DASetFieldName(DMMGGetDA(dmmg),1,"y-velocity");
195:   DASetFieldName(DMMGGetDA(dmmg),2,"pressure");
196:   DASetFieldName(DMMGGetDA(dmmg),3,"temperature");
197:   VecDuplicate(dmmg[0]->x, &(user->Xguess));
198: #else
199:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
200:      Create distributed array multigrid object (DMMG) to manage parallel grid and vectors
201:      for principal unknowns (x) and governing residuals (f)
202:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
203:   DMMGCreate(comm,grid.mglevels,&user,&dmmg);
204:   DACreate2d(comm,grid.periodic,grid.stencil,grid.ni,grid.nj,PETSC_DECIDE,PETSC_DECIDE,grid.dof,grid.stencil_width,0,0,&da);
205:   DMMGSetDM(dmmg,(DM)da);
206:   DADestroy(da);
207:   DASetFieldName(DMMGGetDA(dmmg),0,"x-velocity");
208:   DASetFieldName(DMMGGetDA(dmmg),1,"y-velocity");
209:   DASetFieldName(DMMGGetDA(dmmg),2,"pressure");
210:   DASetFieldName(DMMGGetDA(dmmg),3,"temperature");

212:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
213:      Create user context, set problem data, create vector data structures.
214:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
215:   PetscMalloc(sizeof(AppCtx),&user);
216:   user->param   = &param;
217:   user->grid    = &grid;
218:   dmmg[0]->user = user;
219:   VecDuplicate(dmmg[0]->x, &(user->Xguess));
220: #endif

222:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
223:      Set up the SNES solver with callback functions.
224:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
225:   DMMGSetSNESLocal(dmmg,FormFunctionLocal,0,0,0);
226:   DMMGSetFromOptions(dmmg);
227:   DMMGSetInitialGuess(dmmg,FormInitialGuess);
228:   SNESSetConvergenceTest(DMMGGetSNES(dmmg),SNESConverged_Interactive,(void*)user,PETSC_NULL);
229:   PetscPushSignalHandler(InteractiveHandler,(void*)user);
230: 
231:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
232:      Initialize and solve the nonlinear system
233:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
234:   Initialize(dmmg);
235:   UpdateSolution(dmmg,user,&nits);
236: 
237:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
238:      Output variables.
239:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
240:   DoOutput(dmmg,nits);
241: 
242:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
243:      Free work space. 
244:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
245:   VecDestroy(user->Xguess);
246:   PetscFree(user);
247:   DMMGDestroy(dmmg);
248: 
249:   PetscFinalize();
250:   return 0;
251: }

253: /*=====================================================================
254:   PETSc INTERACTION FUNCTIONS (initialize & call SNESSolve)
255:   =====================================================================*/

257: /*---------------------------------------------------------------------*/
260: /*  manages solve: adaptive continuation method  */
261: PetscErrorCode UpdateSolution(DMMG *dmmg, AppCtx *user, PetscInt *nits)
262: {
263:   SNES                snes;
264:   KSP                 ksp;
265:   PC                  pc;
266:   SNESConvergedReason reason;
267:   Parameter           *param = user->param;
268:   PassiveScalar       cont_incr=0.3;
269:   PetscInt            its;
270:   PetscErrorCode      ierr;
271:   PetscTruth          q = PETSC_FALSE;

274:   snes = DMMGGetSNES(dmmg);
275:   SNESGetKSP(snes,&ksp);
276:   KSPGetPC(ksp, &pc);
277:   KSPSetComputeSingularValues(ksp, PETSC_TRUE);

279:   *nits=0;

281:   /* Isoviscous solve */
282:   if (param->ivisc == VISC_CONST && !param->stop_solve) {
283:     param->ivisc = VISC_CONST;
284:     DMMGSolve(dmmg);
285:     VecCopy(DMMGGetx(dmmg),user->Xguess);
286:     SNESGetIterationNumber(snes, &its);
287:     *nits +=its;
288:     if (param->stop_solve) goto done;
289:   }

291:   /* Olivine diffusion creep */
292:   if (param->ivisc >= VISC_DIFN && !param->stop_solve) {
293:     if (!q) PetscPrintf(PETSC_COMM_WORLD,"Computing Variable Viscosity Solution\n");

295:     /* continuation method on viscosity cutoff */
296:     for (param->continuation=0.0; ; param->continuation+=cont_incr) {
297:       if (!q) PetscPrintf(PETSC_COMM_WORLD," Continuation parameter = %G\n", param->continuation);

299:       /* solve the non-linear system */
300:       DMMGSolve(dmmg);
301:       SNESGetConvergedReason(snes,&reason);
302:       SNESGetIterationNumber(snes,&its);
303:       *nits += its;
304:       if (!q) PetscPrintf(PETSC_COMM_WORLD," Newton iterations: %D, Cumulative: %D\n", its, *nits);
305:       if (param->stop_solve) goto done;

307:       if (reason<0) {
308:         /* NOT converged */
309:         cont_incr = -fabs(cont_incr)/2.0;
310:         if (fabs(cont_incr)<0.01) goto done;

312:       } else {
313:         /* converged */
314:         VecCopy(DMMGGetx(dmmg),user->Xguess);
315:         if (param->continuation >= 1.0) goto done;
316:         if (its<=3) {
317:           cont_incr = 0.30001;
318:         } else if (its<=8) {
319:           cont_incr = 0.15001;
320:         } else {
321:           cont_incr = 0.10001;
322:         }
323:         if (param->continuation+cont_incr > 1.0) {
324:           cont_incr = 1.0 - param->continuation;
325:         }
326:       } /* endif reason<0 */
327:     }
328:   }
329:   done:
330:   if (param->stop_solve && !q) PetscPrintf(PETSC_COMM_WORLD,"USER SIGNAL: stopping solve.\n");
331:   if (reason<0 && !q) PetscPrintf(PETSC_COMM_WORLD,"FAILED TO CONVERGE: stopping solve.\n");
332:   return(0);
333: }

335: /* ------------------------------------------------------------------- */
338: /*  used by SNESSolve to get an initial guess for the solution X */
339: PetscErrorCode FormInitialGuess(DMMG dmmg,Vec X)
340: /* ------------------------------------------------------------------- */
341: {
342:   AppCtx         *user = (AppCtx*)dmmg->user;

345:   VecCopy(user->Xguess, X);
346:   return 0;
347: }

349: /*=====================================================================
350:   PHYSICS FUNCTIONS (compute the discrete residual)
351:   =====================================================================*/

353: /*---------------------------------------------------------------------*/
356: /*  main call-back function that computes the processor-local piece 
357:     of the residual */
358: PetscErrorCode FormFunctionLocal(DALocalInfo *info,Field **x,Field **f,void *ptr)
359: /*---------------------------------------------------------------------*/
360: {
361:   AppCtx         *user = (AppCtx*)ptr;
362:   Parameter      *param = user->param;
363:   GridInfo       *grid  = user->grid;
364:   PetscScalar    mag_w, mag_u;
365:   PetscInt       i,j,mx,mz,ilim,jlim;
366:   PetscInt       is,ie,js,je,ivisc,ibound;


370:   /* Define global and local grid parameters */
371:   mx   = info->mx;     mz   = info->my;
372:   ilim = mx-1;         jlim = mz-1;
373:   is   = info->xs;     ie   = info->xs+info->xm;
374:   js   = info->ys;     je   = info->ys+info->ym;

376:   /* Define geometric and numeric parameters */
377:   ivisc = param->ivisc;       ibound = param->ibound;

379:   for (j=js; j<je; j++) {
380:     for (i=is; i<ie; i++) {

382:       /************* X-MOMENTUM/VELOCITY *************/
383:       if (i<j) {
384:           f[j][i].u = x[j][i].u - SlabVel('U',i,j,user);

386:       } else if (j<=grid->jlid || (j<grid->corner+grid->inose && i<grid->corner+grid->inose)) {
387:         /* in the lithospheric lid */
388:         f[j][i].u = x[j][i].u - 0.0;

390:       } else if (i==ilim) {
391:         /* on the right side boundary */
392:         if (ibound==BC_ANALYTIC) {
393:           f[j][i].u = x[j][i].u - HorizVelocity(i,j,user);
394:         } else {
395:           f[j][i].u = XNormalStress(x,i,j,CELL_CENTER,user) - EPS_ZERO;
396:         }

398:       } else if (j==jlim) {
399:         /* on the bottom boundary */
400:         if (ibound==BC_ANALYTIC) {
401:           f[j][i].u = x[j][i].u - HorizVelocity(i,j,user);
402:         } else if (ibound==BC_NOSTRESS) {
403:           f[j][i].u = XMomentumResidual(x,i,j,user);
404:         } else {
405:           /* experimental boundary condition */
406:         }

408:       } else {
409:         /* in the mantle wedge */
410:         f[j][i].u = XMomentumResidual(x,i,j,user);
411:       }
412: 
413:       /************* Z-MOMENTUM/VELOCITY *************/
414:       if (i<=j) {
415:         f[j][i].w = x[j][i].w - SlabVel('W',i,j,user);

417:       } else if (j<=grid->jlid || (j<grid->corner+grid->inose && i<grid->corner+grid->inose)) {
418:         /* in the lithospheric lid */
419:         f[j][i].w = x[j][i].w - 0.0;

421:       } else if (j==jlim) {
422:         /* on the bottom boundary */
423:         if (ibound==BC_ANALYTIC) {
424:           f[j][i].w = x[j][i].w - VertVelocity(i,j,user);
425:         } else {
426:           f[j][i].w = ZNormalStress(x,i,j,CELL_CENTER,user) - EPS_ZERO;
427:         }

429:       } else if (i==ilim) {
430:         /* on the right side boundary */
431:         if (ibound==BC_ANALYTIC) {
432:           f[j][i].w = x[j][i].w - VertVelocity(i,j,user);
433:         } else if (ibound==BC_NOSTRESS) {
434:           f[j][i].w = ZMomentumResidual(x,i,j,user);
435:         } else {
436:           /* experimental boundary condition */
437:         }

439:       } else {
440:         /* in the mantle wedge */
441:         f[j][i].w =  ZMomentumResidual(x,i,j,user);
442:       }

444:       /************* CONTINUITY/PRESSURE *************/
445:       if (i<j || j<=grid->jlid || (j<grid->corner+grid->inose && i<grid->corner+grid->inose)) {
446:         /* in the lid or slab */
447:         f[j][i].p = x[j][i].p;
448: 
449:       } else if ((i==ilim || j==jlim) && ibound==BC_ANALYTIC) {
450:         /* on an analytic boundary */
451:         f[j][i].p = x[j][i].p - Pressure(i,j,user);

453:       } else {
454:         /* in the mantle wedge */
455:         f[j][i].p = ContinuityResidual(x,i,j,user);
456:       }

458:       /************* TEMPERATURE *************/
459:       if (j==0) {
460:         /* on the surface */
461:         f[j][i].T = x[j][i].T + x[j+1][i].T + PetscMax(x[j][i].T,0.0);

463:       } else if (i==0) {
464:         /* slab inflow boundary */
465:         f[j][i].T = x[j][i].T - PlateModel(j,PLATE_SLAB,user);

467:       } else if (i==ilim) {
468:         /* right side boundary */
469:         mag_u = 1.0 - pow( (1.0-PetscMax(PetscMin(x[j][i-1].u/param->cb,1.0),0.0)), 5.0 );
470:         f[j][i].T = x[j][i].T - mag_u*x[j-1][i-1].T - (1.0-mag_u)*PlateModel(j,PLATE_LID,user);

472:       } else if (j==jlim) {
473:         /* bottom boundary */
474:         mag_w = 1.0 - pow( (1.0-PetscMax(PetscMin(x[j-1][i].w/param->sb,1.0),0.0)), 5.0 );
475:         f[j][i].T = x[j][i].T - mag_w*x[j-1][i-1].T - (1.0-mag_w);

477:       } else {
478:         /* in the mantle wedge */
479:         f[j][i].T = EnergyResidual(x,i,j,user);
480:       }
481:     }
482:   }
483:   return(0);
484: }

486: /*---------------------------------------------------------------------*/
489: /*  computes the residual of the x-component of eqn (1) above */
490: PetscScalar XMomentumResidual(Field **x, PetscInt i, PetscInt j, AppCtx *user)
491: /*---------------------------------------------------------------------*/
492: {
493:   Parameter      *param=user->param;
494:   GridInfo       *grid =user->grid;
495:   PetscScalar    dx = grid->dx, dz=grid->dz;
496:   PetscScalar    etaN,etaS,etaE,etaW,epsN=0.0,epsS=0.0,epsE=0.0,epsW=0.0;
497:   PetscScalar    TE=0.0,TN=0.0,TS=0.0,TW=0.0, dPdx, residual, z_scale;
498:   PetscScalar    dudxW,dudxE,dudzN,dudzS,dwdxN,dwdxS;
499:   PetscInt            jlim = grid->nj-1;

501:   z_scale = param->z_scale;

503:   if ( param->ivisc==VISC_DIFN || param->ivisc>=VISC_DISL ) { /* viscosity is T-dependent */
504:     TS = param->potentialT * TInterp(x,i,j-1) * exp( (j-1.0)*dz*z_scale );
505:     if (j==jlim) TN = TS;
506:     else         TN = param->potentialT * TInterp(x,i,j)   * exp(  j     *dz*z_scale );
507:     TW = param->potentialT * x[j][i].T        * exp( (j-0.5)*dz*z_scale );
508:     TE = param->potentialT * x[j][i+1].T      * exp( (j-0.5)*dz*z_scale );
509:     if (param->ivisc>=VISC_DISL) { /* olivine dislocation creep */
510:       epsN = CalcSecInv(x,i,j,  CELL_CORNER,user);
511:       epsS = CalcSecInv(x,i,j-1,CELL_CORNER,user);
512:       epsE = CalcSecInv(x,i+1,j,CELL_CENTER,user);
513:       epsW = CalcSecInv(x,i,j,  CELL_CENTER,user);
514:     }
515:   }
516:   etaN = Viscosity(TN,epsN,dz*(j+0.5),param);
517:   etaS = Viscosity(TS,epsS,dz*(j-0.5),param);
518:   etaW = Viscosity(TW,epsW,dz*j,param);
519:   etaE = Viscosity(TE,epsE,dz*j,param);

521:   dPdx = ( x[j][i+1].p - x[j][i].p )/dx;
522:   if (j==jlim) dudzN = etaN * ( x[j][i].w   - x[j][i+1].w )/dx;
523:   else         dudzN = etaN * ( x[j+1][i].u - x[j][i].u   )/dz;
524:   dudzS = etaS * ( x[j][i].u    - x[j-1][i].u )/dz;
525:   dudxE = etaE * ( x[j][i+1].u  - x[j][i].u   )/dx;
526:   dudxW = etaW * ( x[j][i].u    - x[j][i-1].u )/dx;

528:   residual  = -dPdx                         /* X-MOMENTUM EQUATION*/
529:               +( dudxE - dudxW )/dx
530:               +( dudzN - dudzS )/dz;

532:   if ( param->ivisc!=VISC_CONST ) {
533:     dwdxN = etaN * ( x[j][i+1].w   - x[j][i].w   )/dx;
534:     dwdxS = etaS * ( x[j-1][i+1].w - x[j-1][i].w )/dx;

536:     residual += ( dudxE - dudxW )/dx + ( dwdxN - dwdxS )/dz;
537:   }

539:   return residual;
540: }

542: /*---------------------------------------------------------------------*/
545: /*  computes the residual of the z-component of eqn (1) above */
546: PetscScalar ZMomentumResidual(Field **x, PetscInt i, PetscInt j, AppCtx *user)
547: /*---------------------------------------------------------------------*/
548: {
549:   Parameter      *param=user->param;
550:   GridInfo       *grid =user->grid;
551:   PetscScalar    dx = grid->dx, dz=grid->dz;
552:   PetscScalar    etaN=0.0,etaS=0.0,etaE=0.0,etaW=0.0,epsN=0.0,epsS=0.0,epsE=0.0,epsW=0.0;
553:   PetscScalar    TE=0.0,TN=0.0,TS=0.0,TW=0.0, dPdz, residual,z_scale;
554:   PetscScalar    dudzE,dudzW,dwdxW,dwdxE,dwdzN,dwdzS;
555:   PetscInt            ilim = grid->ni-1;

557:   /* geometric and other parameters */
558:   z_scale = param->z_scale;
559: 
560:   /* viscosity */
561:   if ( param->ivisc==VISC_DIFN || param->ivisc>=VISC_DISL ) { /* viscosity is T-dependent */
562:     TN = param->potentialT * x[j+1][i].T      * exp( (j+0.5)*dz*z_scale );
563:     TS = param->potentialT * x[j][i].T        * exp( (j-0.5)*dz*z_scale );
564:     TW = param->potentialT * TInterp(x,i-1,j) * exp(  j     *dz*z_scale );
565:     if (i==ilim) TE = TW;
566:     else         TE = param->potentialT * TInterp(x,i,j)   * exp(  j*dz*z_scale );
567:     if (param->ivisc>=VISC_DISL) { /* olivine dislocation creep */
568:       epsN = CalcSecInv(x,i,j+1,CELL_CENTER,user);
569:       epsS = CalcSecInv(x,i,j,  CELL_CENTER,user);
570:       epsE = CalcSecInv(x,i,j,  CELL_CORNER,user);
571:       epsW = CalcSecInv(x,i-1,j,CELL_CORNER,user);
572:     }
573:   }
574:   etaN = Viscosity(TN,epsN,dz*(j+1),param);
575:   etaS = Viscosity(TS,epsS,dz*j,param);
576:   etaW = Viscosity(TW,epsW,dz*(j+0.5),param);
577:   etaE = Viscosity(TE,epsE,dz*(j+0.5),param);

579:   dPdz = ( x[j+1][i].p - x[j][i].p )/dz;
580:   dwdzN = etaN * ( x[j+1][i].w - x[j][i].w )/dz;
581:   dwdzS = etaS * ( x[j][i].w - x[j-1][i].w )/dz;
582:   if (i==ilim) dwdxE = etaE * ( x[j][i].u   - x[j+1][i].u )/dz;
583:   else         dwdxE = etaE * ( x[j][i+1].w - x[j][i].w   )/dx;
584:   dwdxW = 2.0*etaW * ( x[j][i].w - x[j][i-1].w )/dx;
585: 
586:   /* Z-MOMENTUM */
587:   residual  = -dPdz                /* constant viscosity terms */
588:               +( dwdzN - dwdzS )/dz
589:               +( dwdxE - dwdxW )/dx;

591:   if ( param->ivisc!=VISC_CONST ) {
592:     dudzE = etaE * ( x[j+1][i].u - x[j][i].u )/dz;
593:     dudzW = etaW * ( x[j+1][i-1].u - x[j][i-1].u )/dz;

595:     residual += ( dwdzN - dwdzS )/dz + ( dudzE - dudzW )/dx;
596:   }

598:   return residual;
599: }

601: /*---------------------------------------------------------------------*/
604: /*  computes the residual of eqn (2) above */
605: PetscScalar ContinuityResidual(Field **x, PetscInt i, PetscInt j, AppCtx *user)
606: /*---------------------------------------------------------------------*/
607: {
608:   GridInfo       *grid =user->grid;
609:   PetscScalar    uE,uW,wN,wS,dudx,dwdz;

611:   uW = x[j][i-1].u; uE = x[j][i].u; dudx = ( uE - uW )/grid->dx;
612:   wS = x[j-1][i].w; wN = x[j][i].w; dwdz = ( wN - wS )/grid->dz;

614:   return dudx + dwdz;
615: }

617: /*---------------------------------------------------------------------*/
620: /*  computes the residual of eqn (3) above */
621: PetscScalar EnergyResidual(Field **x, PetscInt i, PetscInt j, AppCtx *user)
622: /*---------------------------------------------------------------------*/
623: {
624:   Parameter      *param=user->param;
625:   GridInfo       *grid =user->grid;
626:   PetscScalar    dx = grid->dx, dz=grid->dz;
627:   PetscInt            ilim=grid->ni-1, jlim=grid->nj-1, jlid=grid->jlid;
628:   PetscScalar    TE, TN, TS, TW, residual;
629:   PetscScalar    uE,uW,wN,wS;
630:   PetscScalar    fN,fS,fE,fW,dTdxW,dTdxE,dTdzN,dTdzS;

632:   dTdzN = ( x[j+1][i].T - x[j][i].T   )/dz;
633:   dTdzS = ( x[j][i].T   - x[j-1][i].T )/dz;
634:   dTdxE = ( x[j][i+1].T - x[j][i].T   )/dx;
635:   dTdxW = ( x[j][i].T   - x[j][i-1].T )/dx;
636: 
637:   residual = ( ( dTdzN - dTdzS )/dz + /* diffusion term */
638:                ( dTdxE - dTdxW )/dx  )*dx*dz/param->peclet;

640:   if (j<=jlid && i>=j) {
641:     /* don't advect in the lid */
642:     return residual;

644:   } else if (i<j) {
645:     /* beneath the slab sfc */
646:     uW = uE = param->cb;
647:     wS = wN = param->sb;

649:   } else {
650:     /* advect in the slab and wedge */
651:     uW = x[j][i-1].u; uE = x[j][i].u;
652:     wS = x[j-1][i].w; wN = x[j][i].w;
653:   }

655:   if ( param->adv_scheme==ADVECT_FV || i==ilim-1 || j==jlim-1 || i==1 || j==1 ) {
656:     /* finite volume advection */
657:     TS  = ( x[j][i].T + x[j-1][i].T )/2.0;
658:     TN  = ( x[j][i].T + x[j+1][i].T )/2.0;
659:     TE  = ( x[j][i].T + x[j][i+1].T )/2.0;
660:     TW  = ( x[j][i].T + x[j][i-1].T )/2.0;
661:     fN = wN*TN*dx; fS = wS*TS*dx;
662:     fE = uE*TE*dz; fW = uW*TW*dz;
663: 
664:   } else {
665:     /* Fromm advection scheme */
666:     fE =     ( uE *(-x[j][i+2].T + 5.0*(x[j][i+1].T+x[j][i].T)-x[j][i-1].T)/8.0
667:                - fabs(uE)*(-x[j][i+2].T + 3.0*(x[j][i+1].T-x[j][i].T)+x[j][i-1].T)/8.0 )*dz;
668:     fW =     ( uW *(-x[j][i+1].T + 5.0*(x[j][i].T+x[j][i-1].T)-x[j][i-2].T)/8.0
669:                - fabs(uW)*(-x[j][i+1].T + 3.0*(x[j][i].T-x[j][i-1].T)+x[j][i-2].T)/8.0 )*dz;
670:     fN =     ( wN *(-x[j+2][i].T + 5.0*(x[j+1][i].T+x[j][i].T)-x[j-1][i].T)/8.0
671:                - fabs(wN)*(-x[j+2][i].T + 3.0*(x[j+1][i].T-x[j][i].T)+x[j-1][i].T)/8.0 )*dx;
672:     fS =     ( wS *(-x[j+1][i].T + 5.0*(x[j][i].T+x[j-1][i].T)-x[j-2][i].T)/8.0
673:                - fabs(wS)*(-x[j+1][i].T + 3.0*(x[j][i].T-x[j-1][i].T)+x[j-2][i].T)/8.0 )*dx;
674:   }
675: 
676:   residual -= ( fE - fW + fN - fS );

678:   return residual;
679: }

681: /*---------------------------------------------------------------------*/
684: /*  computes the shear stress---used on the boundaries */
685: PetscScalar ShearStress(Field **x, PetscInt i, PetscInt j, PetscInt ipos, AppCtx *user)
686: /*---------------------------------------------------------------------*/
687: {
688:   Parameter    *param=user->param;
689:   GridInfo     *grid=user->grid;
690:   PetscInt          ilim=grid->ni-1, jlim=grid->nj-1;
691:   PetscScalar  uN, uS, wE, wW;

693:   if ( j<=grid->jlid || i<j || i==ilim || j==jlim ) return EPS_ZERO;

695:   if (ipos==CELL_CENTER) { /* on cell center */

697:     wE = WInterp(x,i,j-1);
698:     if (i==j) { wW = param->sb; uN = param->cb;}
699:     else      { wW = WInterp(x,i-1,j-1); uN = UInterp(x,i-1,j); }
700:     if (j==grid->jlid+1)  uS = 0.0;
701:     else                  uS = UInterp(x,i-1,j-1);

703:   } else { /* on cell corner */

705:     uN = x[j+1][i].u;         uS = x[j][i].u;
706:     wW = x[j][i].w;           wE = x[j][i+1].w;

708:   }

710:   return (uN-uS)/grid->dz + (wE-wW)/grid->dx;
711: }

713: /*---------------------------------------------------------------------*/
716: /*  computes the normal stress---used on the boundaries */
717: PetscScalar XNormalStress(Field **x, PetscInt i, PetscInt j, PetscInt ipos, AppCtx *user)
718: /*---------------------------------------------------------------------*/
719: {
720:   Parameter      *param=user->param;
721:   GridInfo       *grid =user->grid;
722:   PetscScalar    dx = grid->dx, dz=grid->dz;
723:   PetscInt            ilim=grid->ni-1, jlim=grid->nj-1, ivisc;
724:   PetscScalar    epsC=0.0, etaC, TC, uE, uW, pC, z_scale;
725:   if (i<j || j<=grid->jlid) return EPS_ZERO;

727:   ivisc=param->ivisc;  z_scale = param->z_scale;

729:   if (ipos==CELL_CENTER) { /* on cell center */

731:     TC = param->potentialT * x[j][i].T * exp( (j-0.5)*dz*z_scale );
732:     if (ivisc>=VISC_DISL) epsC = CalcSecInv(x,i,j,CELL_CENTER,user);
733:     etaC = Viscosity(TC,epsC,dz*j,param);

735:     uW = x[j][i-1].u;   uE = x[j][i].u;
736:     pC = x[j][i].p;

738:   } else { /* on cell corner */
739:     if ( i==ilim || j==jlim ) return EPS_ZERO;

741:     TC = param->potentialT * TInterp(x,i,j) * exp( j*dz*z_scale );
742:     if (ivisc>=VISC_DISL) epsC = CalcSecInv(x,i,j,CELL_CORNER,user);
743:     etaC = Viscosity(TC,epsC,dz*(j+0.5),param);

745:     if (i==j) uW = param->sb;
746:     else      uW = UInterp(x,i-1,j);
747:     uE = UInterp(x,i,j); pC = PInterp(x,i,j);
748:   }
749: 
750:   return 2.0*etaC*(uE-uW)/dx - pC;
751: }

753: /*---------------------------------------------------------------------*/
756: /*  computes the normal stress---used on the boundaries */
757: PetscScalar ZNormalStress(Field **x, PetscInt i, PetscInt j, PetscInt ipos, AppCtx *user)
758: /*---------------------------------------------------------------------*/
759: {
760:   Parameter      *param=user->param;
761:   GridInfo       *grid =user->grid;
762:   PetscScalar    dz=grid->dz;
763:   PetscInt            ilim=grid->ni-1, jlim=grid->nj-1, ivisc;
764:   PetscScalar    epsC=0.0, etaC, TC;
765:   PetscScalar    pC, wN, wS, z_scale;
766:   if (i<j || j<=grid->jlid) return EPS_ZERO;

768:   ivisc=param->ivisc;  z_scale = param->z_scale;

770:   if (ipos==CELL_CENTER) { /* on cell center */

772:     TC = param->potentialT * x[j][i].T * exp( (j-0.5)*dz*z_scale );
773:     if (ivisc>=VISC_DISL) epsC = CalcSecInv(x,i,j,CELL_CENTER,user);
774:     etaC = Viscosity(TC,epsC,dz*j,param);
775:     wN = x[j][i].w; wS = x[j-1][i].w; pC = x[j][i].p;

777:   } else { /* on cell corner */
778:     if ( (i==ilim) || (j==jlim) ) return EPS_ZERO;

780:     TC = param->potentialT * TInterp(x,i,j) * exp( j*dz*z_scale );
781:     if (ivisc>=VISC_DISL) epsC = CalcSecInv(x,i,j,CELL_CORNER,user);
782:     etaC = Viscosity(TC,epsC,dz*(j+0.5),param);
783:     if (i==j) wN = param->sb;
784:     else      wN = WInterp(x,i,j);
785:     wS = WInterp(x,i,j-1); pC = PInterp(x,i,j);
786:   }

788:   return  2.0*etaC*(wN-wS)/dz - pC;
789: }

791: /*---------------------------------------------------------------------*/
794: /*  computes the second invariant of the strain rate tensor */
795: PetscScalar CalcSecInv(Field **x, PetscInt i, PetscInt j, PetscInt ipos, AppCtx *user)
796: /*---------------------------------------------------------------------*/
797: {
798:   Parameter     *param = user->param;
799:   GridInfo      *grid  = user->grid;
800:   PetscInt           ilim=grid->ni-1, jlim=grid->nj-1;
801:   PetscScalar   uN,uS,uE,uW,wN,wS,wE,wW;
802:   PetscScalar   eps11, eps12, eps22;

804:   if (i<j) return EPS_ZERO;
805:   if (i==ilim) i--; if (j==jlim) j--;

807:   if (ipos==CELL_CENTER) { /* on cell center */
808:     if (j<=grid->jlid) return EPS_ZERO;

810:     uE = x[j][i].u; uW = x[j][i-1].u;
811:     wN = x[j][i].w; wS = x[j-1][i].w;
812:     wE = WInterp(x,i,j-1);
813:     if (i==j) { uN = param->cb; wW = param->sb; }
814:     else      { uN = UInterp(x,i-1,j); wW = WInterp(x,i-1,j-1); }

816:     if (j==grid->jlid+1) uS = 0.0;
817:     else                 uS = UInterp(x,i-1,j-1);

819:   } else {       /* on CELL_CORNER */
820:     if (j<grid->jlid) return EPS_ZERO;

822:     uN = x[j+1][i].u;  uS = x[j][i].u;
823:     wE = x[j][i+1].w;  wW = x[j][i].w;
824:     if (i==j) { wN = param->sb; uW = param->cb; }
825:     else      { wN = WInterp(x,i,j); uW = UInterp(x,i-1,j); }

827:     if (j==grid->jlid) {
828:       uE = 0.0;  uW = 0.0;
829:       uS = -uN;
830:       wS = -wN;
831:     } else {
832:       uE = UInterp(x,i,j);
833:       wS = WInterp(x,i,j-1);
834:     }
835:   }

837:   eps11 = (uE-uW)/grid->dx;  eps22 = (wN-wS)/grid->dz;
838:   eps12 = 0.5*((uN-uS)/grid->dz + (wE-wW)/grid->dx);

840:   return sqrt( 0.5*( eps11*eps11 + 2.0*eps12*eps12 + eps22*eps22 ) );
841: }

843: /*---------------------------------------------------------------------*/
846: /*  computes the shear viscosity */
847: PetscScalar Viscosity(PetscScalar T, PetscScalar eps, PassiveScalar z, 
848:                        Parameter *param)
849: /*---------------------------------------------------------------------*/
850: {
851:   PetscScalar  result=0.0;
852:   ViscParam    difn=param->diffusion, disl=param->dislocation;
853:   PetscInt          iVisc=param->ivisc;
854:   double       eps_scale=param->V/(param->L*1000.0);
855:   double       strain_power, v1, v2, P;
856:   double       rho_g = 32340.0, R=8.3144;

858:   P = rho_g*(z*param->L*1000.0); /* Pa */

860:   if        (iVisc==VISC_CONST) {
861:     /* constant viscosity */
862:     return 1.0;

864:   } else if (iVisc==VISC_DIFN) {
865:     /* diffusion creep rheology */
866:     result = difn.A*PetscExpScalar((difn.Estar + P*difn.Vstar)/R/(T+273.0))/param->eta0;

868:   } else if (iVisc==VISC_DISL) {
869:     /* dislocation creep rheology */
870:     strain_power = pow( eps*eps_scale, (1.0-disl.n)/disl.n );
871:     result = disl.A*PetscExpScalar((disl.Estar + P*disl.Vstar)/disl.n/R/(T+273.0))*strain_power/param->eta0;

873:   } else if (iVisc==VISC_FULL) {
874:     /* dislocation/diffusion creep rheology */
875:     strain_power = pow( eps*eps_scale, (1.0-disl.n)/disl.n );
876:     v1 = difn.A*PetscExpScalar((difn.Estar + P*difn.Vstar)/R/(T+273.0))/param->eta0;
877:     v2 = disl.A*PetscExpScalar((disl.Estar + P*disl.Vstar)/disl.n/R/(T+273.0))*strain_power/param->eta0;
878:     result = 1.0/(1.0/v1 + 1.0/v2);
879:   }

881:   /* max viscosity is param->eta0 */
882:   result = PetscMin( result, 1.0 );
883:   /* min viscosity is param->visc_cutoff */
884:   result = PetscMax( result, param->visc_cutoff );
885:   /* continuation method */
886:   result = pow(result,param->continuation);
887:   return result;
888: }

890: /*=====================================================================
891:   INITIALIZATION, POST-PROCESSING AND OUTPUT FUNCTIONS 
892:   =====================================================================*/

894: /*---------------------------------------------------------------------*/
897: /* initializes the problem parameters and checks for 
898:    command line changes */
899: PetscErrorCode SetParams(Parameter *param, GridInfo *grid)
900: /*---------------------------------------------------------------------*/
901: {
902:   PetscErrorCode ierr, ierr_out=0;
903:   PetscReal      SEC_PER_YR = 3600.00*24.00*365.2500;
904:   PetscReal      PI = 3.14159265358979323846;
905:   PetscReal      alpha_g_on_cp_units_inverse_km=4.0e-5*9.8;
906: 
907:   /* domain geometry */
908:   param->slab_dip      = 45.0;
909:   param->width         = 320.0;                                            /* km */
910:   param->depth         = 300.0;                                            /* km */
911:   param->lid_depth     = 35.0;                                             /* km */
912:   param->fault_depth   = 35.0;                                             /* km */
913:   PetscOptionsGetReal(PETSC_NULL,"-slab_dip",&(param->slab_dip),PETSC_NULL);
914:   PetscOptionsGetReal(PETSC_NULL,"-width",&(param->width),PETSC_NULL);
915:   PetscOptionsGetReal(PETSC_NULL,"-depth",&(param->depth),PETSC_NULL);
916:   PetscOptionsGetReal(PETSC_NULL,"-lid_depth",&(param->lid_depth),PETSC_NULL);
917:   PetscOptionsGetReal(PETSC_NULL,"-fault_depth",&(param->fault_depth),PETSC_NULL);
918:   param->slab_dip      = param->slab_dip*PI/180.0;                    /* radians */

920:   /* grid information */
921:   PetscOptionsGetInt(PETSC_NULL, "-jfault",&(grid->jfault),PETSC_NULL);
922:   grid->ni             = 82;
923:   PetscOptionsGetInt(PETSC_NULL, "-ni",&(grid->ni),PETSC_NULL);
924:   grid->dx             = param->width/((double)(grid->ni-2));              /* km */
925:   grid->dz             = grid->dx*tan(param->slab_dip);                    /* km */
926:   grid->nj             = (PetscInt)(param->depth/grid->dz + 3.0);        /* gridpoints*/
927:   param->depth         = grid->dz*(grid->nj-2);                            /* km */
928:   grid->inose          = 0;                                         /* gridpoints*/
929:   PetscOptionsGetInt(PETSC_NULL,"-inose",&(grid->inose),PETSC_NULL);
930:   grid->periodic       = DA_NONPERIODIC;
931:   grid->stencil        = DA_STENCIL_BOX;
932:   grid->dof            = 4;
933:   grid->stencil_width  = 2;
934:   grid->mglevels       = 1;

936:   /* boundary conditions */
937:   param->pv_analytic        = PETSC_FALSE;
938:   param->ibound             = BC_NOSTRESS;
939:   PetscOptionsGetInt(PETSC_NULL,"-ibound",&(param->ibound),PETSC_NULL);

941:   /* physical constants */
942:   param->slab_velocity = 5.0;               /* cm/yr */
943:   param->slab_age      = 50.0;              /* Ma */
944:   param->lid_age       = 50.0;              /* Ma */
945:   param->kappa         = 0.7272e-6;         /* m^2/sec */
946:   param->potentialT    = 1300.0;            /* degrees C */
947:   PetscOptionsGetReal(PETSC_NULL,"-slab_velocity",&(param->slab_velocity),PETSC_NULL);
948:   PetscOptionsGetReal(PETSC_NULL,"-slab_age",&(param->slab_age),PETSC_NULL);
949:   PetscOptionsGetReal(PETSC_NULL,"-lid_age",&(param->lid_age),PETSC_NULL);
950:   PetscOptionsGetReal(PETSC_NULL,"-kappa",&(param->kappa),PETSC_NULL);
951:   PetscOptionsGetReal(PETSC_NULL,"-potentialT",&(param->potentialT),PETSC_NULL);

953:   /* viscosity */
954:   param->ivisc         = 3;                 /* 0=isovisc, 1=difn creep, 2=disl creep, 3=full */
955:   param->eta0          = 1e24;              /* Pa-s */
956:   param->visc_cutoff   = 0.0;               /* factor of eta_0 */
957:   param->continuation  = 1.0;
958:   /* constants for diffusion creep */
959:   param->diffusion.A       = 1.8e7;           /* Pa-s */
960:   param->diffusion.n       = 1.0;             /* dim'less */
961:   param->diffusion.Estar   = 375e3;           /* J/mol */
962:   param->diffusion.Vstar   = 5e-6;            /* m^3/mol */
963:   /* constants for param->dislocationocation creep */
964:   param->dislocation.A     = 2.8969e4;        /* Pa-s */
965:   param->dislocation.n     = 3.5;             /* dim'less */
966:   param->dislocation.Estar = 530e3;           /* J/mol */
967:   param->dislocation.Vstar = 14e-6;           /* m^3/mol */
968:   PetscOptionsGetInt(PETSC_NULL, "-ivisc",&(param->ivisc),PETSC_NULL);
969:   PetscOptionsGetReal(PETSC_NULL,"-visc_cutoff",&(param->visc_cutoff),PETSC_NULL);
970:   param->output_ivisc  = param->ivisc;
971:   PetscOptionsGetInt(PETSC_NULL,"-output_ivisc",&(param->output_ivisc),PETSC_NULL);
972:   PetscOptionsGetReal(PETSC_NULL,"-vstar",&(param->dislocation.Vstar),PETSC_NULL);

974:   /* output options */
975:   param->quiet            = PETSC_FALSE;
976:   param->param_test       = PETSC_FALSE;
977:   PetscOptionsHasName(PETSC_NULL,"-quiet",&(param->quiet));
978:   PetscOptionsHasName(PETSC_NULL,"-test",&(param->param_test));
979:   PetscOptionsGetString(PETSC_NULL,"-file",param->filename,PETSC_MAX_PATH_LEN,&(param->output_to_file));

981:   /* advection */
982:   param->adv_scheme       = ADVECT_FROMM;       /* advection scheme: 0=finite vol, 1=Fromm */
983:   PetscOptionsGetInt(PETSC_NULL,"-adv_scheme",&(param->adv_scheme),PETSC_NULL);

985:   /* misc. flags */
986:   param->stop_solve          = PETSC_FALSE;
987:   param->interrupted         = PETSC_FALSE;
988:   param->kspmon              = PETSC_FALSE;
989:   param->toggle_kspmon       = PETSC_FALSE;

991:   /* derived parameters for slab angle */
992:   param->sb  = sin(param->slab_dip);
993:   param->cb  = cos(param->slab_dip);
994:   param->c   =  param->slab_dip*param->sb/(param->slab_dip*param->slab_dip-param->sb*param->sb);
995:   param->d   = (param->slab_dip*param->cb-param->sb)/(param->slab_dip*param->slab_dip-param->sb*param->sb);

997:   /* length, velocity and time scale for non-dimensionalization */
998:   param->L = PetscMin(param->width,param->depth);               /* km */
999:   param->V = param->slab_velocity/100.0/SEC_PER_YR;             /* m/sec */

1001:   /* other unit conversions and derived parameters */
1002:   param->scaled_width  = param->width/param->L;                 /* dim'less */
1003:   param->scaled_depth  = param->depth/param->L;                 /* dim'less */
1004:   param->lid_depth     = param->lid_depth/param->L;             /* dim'less */
1005:   param->fault_depth   = param->fault_depth/param->L;           /* dim'less */
1006:   grid->dx             = grid->dx/param->L;                     /* dim'less */
1007:   grid->dz             = grid->dz/param->L;                     /* dim'less */
1008:   grid->jlid           = (PetscInt)(param->lid_depth/grid->dz);      /* gridcells */
1009:   grid->jfault         = (PetscInt)(param->fault_depth/grid->dz);    /* gridcells */
1010:   param->lid_depth     = grid->jlid*grid->dz;                   /* dim'less */
1011:   param->fault_depth   = grid->jfault*grid->dz;                 /* dim'less */
1012:   grid->corner         = grid->jlid+1;                          /* gridcells */
1013:   param->peclet        = param->V                               /* m/sec */
1014:                        * param->L*1000.0                        /* m */
1015:                        / param->kappa;                          /* m^2/sec */
1016:   param->z_scale       = param->L * alpha_g_on_cp_units_inverse_km;
1017:   param->skt           = sqrt(param->kappa*param->slab_age*SEC_PER_YR);
1018:   PetscOptionsGetReal(PETSC_NULL,"-peclet",&(param->peclet),PETSC_NULL);
1019: 
1020:   return ierr_out;
1021: }

1023: /*---------------------------------------------------------------------*/
1026: /*  prints a report of the problem parameters to stdout */
1027: PetscErrorCode ReportParams(Parameter *param, GridInfo *grid)
1028: /*---------------------------------------------------------------------*/
1029: {
1030:   PetscErrorCode ierr, ierr_out=0;
1031:   char           date[30];
1032:   PetscReal      PI = 3.14159265358979323846;

1034:   PetscGetDate(date,30);

1036:   if ( !(param->quiet) ) {
1037:     PetscPrintf(PETSC_COMM_WORLD,"---------------------BEGIN ex30 PARAM REPORT-------------------\n");
1038:     PetscPrintf(PETSC_COMM_WORLD,"                   %s\n",&(date[0]));

1040:     PetscPrintf(PETSC_COMM_WORLD,"Domain: \n");
1041:     PetscPrintf(PETSC_COMM_WORLD,"  Width = %G km,         Depth = %G km\n",param->width,param->depth);
1042:     PetscPrintf(PETSC_COMM_WORLD,"  Slab dip = %G degrees,  Slab velocity = %G cm/yr\n",param->slab_dip*180.0/PI,param->slab_velocity);
1043:     PetscPrintf(PETSC_COMM_WORLD,"  Lid depth = %5.2f km,   Fault depth = %5.2f km\n",param->lid_depth*param->L,param->fault_depth*param->L);

1045:     PetscPrintf(PETSC_COMM_WORLD,"\nGrid: \n");
1046:     PetscPrintf(PETSC_COMM_WORLD,"  [ni,nj] = %D, %D       [dx,dz] = %G, %G km\n",grid->ni,grid->nj,grid->dx*param->L,grid->dz*param->L);
1047:     PetscPrintf(PETSC_COMM_WORLD,"  jlid = %3D              jfault = %3D \n",grid->jlid,grid->jfault);
1048:     PetscPrintf(PETSC_COMM_WORLD,"  Pe = %G\n",param->peclet);

1050:     PetscPrintf(PETSC_COMM_WORLD,"\nRheology:");
1051:     if (param->ivisc==VISC_CONST) {
1052:       PetscPrintf(PETSC_COMM_WORLD,"                 Isoviscous \n");
1053:       if (param->pv_analytic)
1054:         PetscPrintf(PETSC_COMM_WORLD,"                          Pressure and Velocity prescribed! \n");
1055:     } else if (param->ivisc==VISC_DIFN) {
1056:       PetscPrintf(PETSC_COMM_WORLD,"                 Diffusion Creep (T-Dependent Newtonian) \n");
1057:       PetscPrintf(PETSC_COMM_WORLD,"                          Viscosity range: %G--%G Pa-sec \n",param->eta0,param->visc_cutoff*param->eta0);
1058:     } else if (param->ivisc==VISC_DISL ) {
1059:       PetscPrintf(PETSC_COMM_WORLD,"                 Dislocation Creep (T-Dependent Non-Newtonian) \n");
1060:       PetscPrintf(PETSC_COMM_WORLD,"                          Viscosity range: %G--%G Pa-sec \n",param->eta0,param->visc_cutoff*param->eta0);
1061:     } else if (param->ivisc==VISC_FULL ) {
1062:       PetscPrintf(PETSC_COMM_WORLD,"                 Full Rheology \n");
1063:       PetscPrintf(PETSC_COMM_WORLD,"                          Viscosity range: %G--%G Pa-sec \n",param->eta0,param->visc_cutoff*param->eta0);
1064:     } else {
1065:       PetscPrintf(PETSC_COMM_WORLD,"                 Invalid! \n");
1066:       ierr_out=1;
1067:     }

1069:     PetscPrintf(PETSC_COMM_WORLD,"Boundary condition:");
1070:     if ( param->ibound==BC_ANALYTIC ) {
1071:       PetscPrintf(PETSC_COMM_WORLD,"       Isoviscous Analytic Dirichlet \n");
1072:     } else if ( param->ibound==BC_NOSTRESS ) {
1073:       PetscPrintf(PETSC_COMM_WORLD,"       Stress-Free (normal & shear stress)\n");
1074:     } else if ( param->ibound==BC_EXPERMNT ) {
1075:       PetscPrintf(PETSC_COMM_WORLD,"       Experimental boundary condition \n");
1076:     } else {
1077:       PetscPrintf(PETSC_COMM_WORLD,"       Invalid! \n");
1078:       ierr_out=1;
1079:     }

1081:     if (param->output_to_file)
1082: #if defined(PETSC_HAVE_MATLAB_ENGINE)
1083:       PetscPrintf(PETSC_COMM_WORLD,"Output Destination:       Mat file \"%s\"\n",param->filename);
1084: #else
1085:       PetscPrintf(PETSC_COMM_WORLD,"Output Destination:       PETSc binary file \"%s\"\n",param->filename);
1086: #endif
1087:     if ( param->output_ivisc != param->ivisc )
1088:       PetscPrintf(PETSC_COMM_WORLD,"                          Output viscosity: -ivisc %D\n",param->output_ivisc);

1090:     PetscPrintf(PETSC_COMM_WORLD,"---------------------END ex30 PARAM REPORT---------------------\n");
1091:   }
1092:   if ( param->param_test ) PetscEnd();
1093:   return ierr_out;
1094: }

1096: /* ------------------------------------------------------------------- */
1099: /*  generates an inital guess using the analytic solution for isoviscous
1100:     corner flow */
1101: PetscErrorCode Initialize(DMMG *dmmg)
1102: /* ------------------------------------------------------------------- */
1103: {
1104:   AppCtx         *user = (AppCtx*)dmmg[0]->user;
1105:   Parameter      *param = user->param;
1106:   GridInfo       *grid  = user->grid;
1107:   DA             da;
1108:   PetscInt       i,j,is,js,im,jm;
1110:   Field          **x;

1112:   /* Get the fine grid */
1113:   da = (DA)(dmmg[0]->dm);
1114:   DAGetCorners(da,&is,&js,PETSC_NULL,&im,&jm,PETSC_NULL);
1115:   DAVecGetArray(da,((AppCtx*)dmmg[0]->user)->Xguess,(void**)&x);

1117:   /* Compute initial guess */
1118:   for (j=js; j<js+jm; j++) {
1119:     for (i=is; i<is+im; i++) {
1120:       if (i<j) {
1121:         x[j][i].u  = param->cb;
1122:       } else if (j<=grid->jlid) {
1123:         x[j][i].u  = 0.0;
1124:       } else {
1125:         x[j][i].u  = HorizVelocity(i,j,user);
1126:       }
1127:       if (i<=j) {
1128:         x[j][i].w = param->sb;
1129:       } else if (j<=grid->jlid) {
1130:         x[j][i].w = 0.0;
1131:       } else {
1132:         x[j][i].w = VertVelocity(i,j,user);
1133:       }
1134:       if (i<j || j<=grid->jlid) {
1135:         x[j][i].p = 0.0;
1136:       } else {
1137:         x[j][i].p = Pressure(i,j,user);
1138:       }
1139:       x[j][i].T   = PetscMin(grid->dz*(j-0.5),1.0);
1140:     }
1141:   }

1143:   /* Restore x to Xguess */
1144:   DAVecRestoreArray(da,((AppCtx*)dmmg[0]->user)->Xguess,(void**)&x);

1146:   return 0;
1147: }

1149: /*---------------------------------------------------------------------*/
1152: /*  controls output to a file */
1153: PetscErrorCode DoOutput(DMMG *dmmg, PetscInt its)
1154: /*---------------------------------------------------------------------*/
1155: {
1156:   AppCtx         *user = (AppCtx*)dmmg[0]->user;
1157:   Parameter      *param = user->param;
1158:   GridInfo       *grid  = user->grid;
1160:   PetscMPIInt    rank;
1161:   PetscInt       ivt=param->ivisc;
1162:   PetscViewer    viewer;
1163:   Vec            res, pars;
1164:   MPI_Comm       comm;

1166:   param->ivisc = param->output_ivisc;

1168:   /* compute final residual and final viscosity/strain rate fields */
1169:   SNESGetFunction(DMMGGetSNES(dmmg), &res, PETSC_NULL, PETSC_NULL);
1170:   ViscosityField(DMMGGetDMMG(dmmg), DMMGGetx(dmmg), ((AppCtx *)dmmg[0]->user)->Xguess);

1172:   /* get the communicator and the rank of the processor */
1173:   PetscObjectGetComm((PetscObject)DMMGGetSNES(dmmg), &comm);
1174:   MPI_Comm_rank(comm, &rank);

1176:   if (param->output_to_file) { /* send output to binary file */
1177:     VecCreate(comm, &pars);
1178:     if (rank == 0) { /* on processor 0 */
1179:       VecSetSizes(pars, 20, PETSC_DETERMINE);
1180:       VecSetFromOptions(pars);
1181:       VecSetValue(pars,0, (PetscScalar)(grid->ni),INSERT_VALUES);
1182:       VecSetValue(pars,1, (PetscScalar)(grid->nj),INSERT_VALUES);
1183:       VecSetValue(pars,2, (PetscScalar)(grid->dx),INSERT_VALUES);
1184:       VecSetValue(pars,3, (PetscScalar)(grid->dz),INSERT_VALUES);
1185:       VecSetValue(pars,4, (PetscScalar)(param->L),INSERT_VALUES);
1186:       VecSetValue(pars,5, (PetscScalar)(param->V),INSERT_VALUES);
1187:       /* skipped 6 intentionally */
1188:       VecSetValue(pars,7, (PetscScalar)(param->slab_dip),INSERT_VALUES);
1189:       VecSetValue(pars,8, (PetscScalar)(grid->jlid),INSERT_VALUES);
1190:       VecSetValue(pars,9, (PetscScalar)(param->lid_depth),INSERT_VALUES);
1191:       VecSetValue(pars,10,(PetscScalar)(grid->jfault),INSERT_VALUES);
1192:       VecSetValue(pars,11,(PetscScalar)(param->fault_depth),INSERT_VALUES);
1193:       VecSetValue(pars,12,(PetscScalar)(param->potentialT),INSERT_VALUES);
1194:       VecSetValue(pars,13,(PetscScalar)(param->ivisc),INSERT_VALUES);
1195:       VecSetValue(pars,14,(PetscScalar)(param->visc_cutoff),INSERT_VALUES);
1196:       VecSetValue(pars,15,(PetscScalar)(param->ibound),INSERT_VALUES);
1197:       VecSetValue(pars,16,(PetscScalar)(its),INSERT_VALUES);
1198:     } else { /* on some other processor */
1199:       VecSetSizes(pars, 0, PETSC_DETERMINE);
1200:       VecSetFromOptions(pars);
1201:     }
1202:     VecAssemblyBegin(pars); VecAssemblyEnd(pars);

1204:     /* create viewer */
1205: #if defined(PETSC_HAVE_MATLAB_ENGINE)
1206:     PetscViewerMatlabOpen(PETSC_COMM_WORLD,param->filename,FILE_MODE_WRITE,&viewer);
1207: #else
1208:     PetscViewerBinaryOpen(PETSC_COMM_WORLD,param->filename,FILE_MODE_WRITE,&viewer);
1209: #endif

1211:     /* send vectors to viewer */
1212:     PetscObjectSetName((PetscObject)res,"res");
1213:     VecView(res,viewer);
1214:     PetscObjectSetName((PetscObject)DMMGGetx(dmmg),"out");
1215:     VecView(DMMGGetx(dmmg), viewer);
1216:     PetscObjectSetName((PetscObject)(user->Xguess),"aux");
1217:     VecView(user->Xguess, viewer);
1218:     StressField(dmmg); /* compute stress fields */
1219:     PetscObjectSetName((PetscObject)(user->Xguess),"str");
1220:     VecView(user->Xguess, viewer);
1221:     PetscObjectSetName((PetscObject)pars,"par");
1222:     VecView(pars, viewer);
1223: 
1224:     /* destroy viewer and vector */
1225:     PetscViewerDestroy(viewer);
1226:     VecDestroy(pars);
1227:   }
1228: 
1229:   param->ivisc = ivt;
1230:   return 0;
1231: }

1233: /* ------------------------------------------------------------------- */
1236: /* Compute both the second invariant of the strain rate tensor and the viscosity, at both cell centers and cell corners */
1237: PetscErrorCode ViscosityField(DMMG dmmg, Vec X, Vec V)
1238: /* ------------------------------------------------------------------- */
1239: {
1240:   DA             da    = (DA) dmmg->dm;
1241:   AppCtx         *user  = (AppCtx *) dmmg->user;
1242:   Parameter      *param = user->param;
1243:   GridInfo       *grid  = user->grid;
1244:   Vec            localX;
1245:   Field          **v, **x;
1246:   PassiveReal    eps, dx, dz, T, epsC, TC;
1247:   PetscInt       i,j,is,js,im,jm,ilim,jlim,ivt;

1251:   ivt          = param->ivisc;
1252:   param->ivisc = param->output_ivisc;

1254:   DACreateLocalVector(da, &localX);
1255:   DAGlobalToLocalBegin(da, X, INSERT_VALUES, localX);
1256:   DAGlobalToLocalEnd(da, X, INSERT_VALUES, localX);
1257:   DAVecGetArray(da,localX,(void**)&x);
1258:   DAVecGetArray(da,V,(void**)&v);

1260:   /* Parameters */
1261:   dx   = grid->dx;   dz   = grid->dz;
1262:   ilim = grid->ni-1; jlim = grid->nj-1;

1264:   /* Compute real temperature, strain rate and viscosity */
1265:   DAGetCorners(da,&is,&js,PETSC_NULL,&im,&jm,PETSC_NULL);
1266:   for (j=js; j<js+jm; j++) {
1267:     for (i=is; i<is+im; i++) {
1268:       T  = param->potentialT * x[j][i].T * exp( (j-0.5)*dz*param->z_scale );
1269:       if (i<ilim && j<jlim) {
1270:         TC = param->potentialT * TInterp(x,i,j) * exp( j*dz*param->z_scale );
1271:       } else {
1272:         TC = T;
1273:       }
1274:       eps  = CalcSecInv(x,i,j,CELL_CENTER,user);
1275:       epsC = CalcSecInv(x,i,j,CELL_CORNER,user);
1276:       v[j][i].u = eps;
1277:       v[j][i].w = epsC;
1278:       v[j][i].p = Viscosity(T,eps,dz*(j-0.5),param);
1279:       v[j][i].T = Viscosity(TC,epsC,dz*j,param);
1280:     }
1281:   }
1282:   DAVecRestoreArray(da,V,(void**)&v);
1283:   DAVecRestoreArray(da,localX,(void**)&x);
1284:   param->ivisc = ivt;
1285:   return(0);
1286: }

1288: /* ------------------------------------------------------------------- */
1291: /* post-processing: compute stress everywhere */
1292: PetscErrorCode StressField(DMMG *dmmg)
1293: /* ------------------------------------------------------------------- */
1294: {
1295:   AppCtx         *user = (AppCtx*)dmmg[0]->user;
1296:   PetscInt       i,j,is,js,im,jm;
1298:   DA             da;
1299:   Vec            locVec;
1300:   Field          **x, **y;

1302:   /* Get the fine grid of Xguess and X */
1303:   da = (DA)(dmmg[0]->dm);
1304:   DAGetCorners(da,&is,&js,PETSC_NULL,&im,&jm,PETSC_NULL);
1305:   DAVecGetArray(da,((AppCtx*)dmmg[0]->user)->Xguess,(void**)&x);

1307:   DACreateLocalVector(da, &locVec);
1308:   DAGlobalToLocalBegin(da, DMMGGetx(dmmg), INSERT_VALUES, locVec);
1309:   DAGlobalToLocalEnd(da, DMMGGetx(dmmg), INSERT_VALUES, locVec);
1310:   DAVecGetArray(da,locVec,(void**)&y);

1312:   /* Compute stress on the corner points */
1313:   for (j=js; j<js+jm; j++) {
1314:      for (i=is; i<is+im; i++) {
1315: 
1316:         x[j][i].u = ShearStress(y,i,j,CELL_CENTER,user);
1317:         x[j][i].w = ShearStress(y,i,j,CELL_CORNER,user);
1318:         x[j][i].p = XNormalStress(y,i,j,CELL_CENTER,user);
1319:         x[j][i].T = ZNormalStress(y,i,j,CELL_CENTER,user);
1320:     }
1321:   }

1323:   /* Restore the fine grid of Xguess and X */
1324:   DAVecRestoreArray(da,((AppCtx*)dmmg[0]->user)->Xguess,(void**)&x);
1325:   DAVecRestoreArray(da,locVec,(void**)&y);

1327:   return 0;
1328: }

1330: /*=====================================================================
1331:   UTILITY FUNCTIONS 
1332:   =====================================================================*/

1334: /*---------------------------------------------------------------------*/
1337: /* returns the velocity of the subducting slab and handles fault nodes 
1338:    for BC */
1339: PassiveScalar SlabVel(char c, PetscInt i, PetscInt j, AppCtx *user)
1340: /*---------------------------------------------------------------------*/
1341: {
1342:   Parameter     *param = user->param;
1343:   GridInfo      *grid  = user->grid;

1345:   if (c=='U' || c=='u') {
1346:     if (i<j-1) {
1347:       return param->cb;
1348:     } else if (j<=grid->jfault) {
1349:       return 0.0;
1350:     } else
1351:       return param->cb;

1353:   } else {
1354:     if (i<j) {
1355:       return param->sb;
1356:     } else if (j<=grid->jfault) {
1357:       return 0.0;
1358:     } else
1359:       return param->sb;
1360:   }
1361: }

1363: /*---------------------------------------------------------------------*/
1366: /*  solution to diffusive half-space cooling model for BC */
1367: PassiveScalar PlateModel(PetscInt j, PetscInt plate, AppCtx *user)
1368: /*---------------------------------------------------------------------*/
1369: {
1370:   Parameter     *param = user->param;
1371:   PassiveScalar z;
1372:   if (plate==PLATE_LID)
1373:     z = (j-0.5)*user->grid->dz;
1374:   else /* PLATE_SLAB */
1375:     z = (j-0.5)*user->grid->dz*param->cb;
1376: #if defined (PETSC_HAVE_ERF)
1377:   return erf(z*param->L/2.0/param->skt);
1378: #else
1379:   SETERRQ(1,"erf() not available on this machine");
1380: #endif
1381: }

1383: /*---------------------------------------------------------------------*/
1386: PetscScalar UInterp(Field **x, PetscInt i, PetscInt j)
1387: /*---------------------------------------------------------------------*/
1388: {
1389:   return 0.25*(x[j][i].u+x[j+1][i].u+x[j][i+1].u+x[j+1][i+1].u);
1390: }

1392: /*---------------------------------------------------------------------*/
1395: PetscScalar WInterp(Field **x, PetscInt i, PetscInt j)
1396: /*---------------------------------------------------------------------*/
1397: {
1398:   return 0.25*(x[j][i].w+x[j+1][i].w+x[j][i+1].w+x[j+1][i+1].w);
1399: }

1401: /*---------------------------------------------------------------------*/
1404: PetscScalar PInterp(Field **x, PetscInt i, PetscInt j)
1405: /*---------------------------------------------------------------------*/
1406: {
1407:   return 0.25*(x[j][i].p+x[j+1][i].p+x[j][i+1].p+x[j+1][i+1].p);
1408: }

1410: /*---------------------------------------------------------------------*/
1413: PetscScalar TInterp(Field **x, PetscInt i, PetscInt j)
1414: /*---------------------------------------------------------------------*/
1415: {
1416:   return 0.25*(x[j][i].T+x[j+1][i].T+x[j][i+1].T+x[j+1][i+1].T);
1417: }

1419: /*---------------------------------------------------------------------*/
1422: /*  isoviscous analytic solution for IC */
1423: PassiveScalar HorizVelocity(PetscInt i, PetscInt j, AppCtx *user)
1424: /*---------------------------------------------------------------------*/
1425: {
1426:   Parameter   *param = user->param;
1427:   GridInfo    *grid  = user->grid;
1428:   PetscScalar x, z, r, st, ct, th, c=param->c, d=param->d;
1429: 
1430:   x = (i - grid->jlid)*grid->dx;  z = (j - grid->jlid - 0.5)*grid->dz;
1431:   r = sqrt(x*x+z*z); st = z/r;  ct = x/r;  th = atan(z/x);
1432:   return ct*(c*th*st+d*(st+th*ct)) + st*(c*(st-th*ct)+d*th*st);
1433: }

1435: /*---------------------------------------------------------------------*/
1438: /*  isoviscous analytic solution for IC */
1439: PetscScalar VertVelocity(PetscInt i, PetscInt j, AppCtx *user)
1440: /*---------------------------------------------------------------------*/
1441: {
1442:   Parameter   *param = user->param;
1443:   GridInfo    *grid  = user->grid;
1444:   PetscScalar x, z, r, st, ct, th, c=param->c, d=param->d;
1445: 
1446:   x = (i - grid->jlid - 0.5)*grid->dx;  z = (j - grid->jlid)*grid->dz;
1447:   r = sqrt(x*x+z*z); st = z/r;  ct = x/r;  th = atan(z/x);
1448:   return st*(c*th*st+d*(st+th*ct)) - ct*(c*(st-th*ct)+d*th*st);
1449: }

1451: /*---------------------------------------------------------------------*/
1454: /*  isoviscous analytic solution for IC */
1455: PetscScalar Pressure(PetscInt i, PetscInt j, AppCtx *user)
1456: /*---------------------------------------------------------------------*/
1457: {
1458:   Parameter   *param = user->param;
1459:   GridInfo    *grid  = user->grid;
1460:   PetscScalar x, z, r, st, ct, c=param->c, d=param->d;

1462:   x = (i - grid->jlid - 0.5)*grid->dx;  z = (j - grid->jlid - 0.5)*grid->dz;
1463:   r = sqrt(x*x+z*z);  st = z/r;  ct = x/r;
1464:   return (-2.0*(c*ct-d*st)/r);
1465: }

1467: /* ------------------------------------------------------------------- */
1470: /*  utility function */
1471: PetscTruth OptionsHasName(const char pre[],const char name[])
1472: /* ------------------------------------------------------------------- */
1473: {
1474:   PetscTruth     retval;
1476:   PetscOptionsHasName(pre,name,&retval);
1477:   return retval;
1478: }

1480: /*=====================================================================
1481:   INTERACTIVE SIGNAL HANDLING 
1482:   =====================================================================*/

1484: /* ------------------------------------------------------------------- */
1487: PetscErrorCode SNESConverged_Interactive(SNES snes, PetscInt it,PetscReal xnorm, PetscReal pnorm, PetscReal fnorm, SNESConvergedReason *reason, void *ctx)
1488: /* ------------------------------------------------------------------- */
1489: {
1490:   AppCtx        *user = (AppCtx *) ctx;
1491:   Parameter     *param = user->param;
1492:   KSP            ksp;

1496:   if (param->interrupted) {
1497:     param->interrupted = PETSC_FALSE;
1498:     PetscPrintf(PETSC_COMM_WORLD,"USER SIGNAL: exiting SNES solve. \n");
1499:     *reason = SNES_CONVERGED_FNORM_ABS;
1500:     return(0);
1501:   } else if (param->toggle_kspmon) {
1502:     param->toggle_kspmon = PETSC_FALSE;
1503:     SNESGetKSP(snes, &ksp);
1504:     if (param->kspmon) {
1505:       KSPMonitorCancel(ksp);
1506:       param->kspmon = PETSC_FALSE;
1507:       PetscPrintf(PETSC_COMM_WORLD,"USER SIGNAL: deactivating ksp singular value monitor. \n");
1508:     } else {
1509:       KSPMonitorSet(ksp,KSPMonitorSingularValue,PETSC_NULL,PETSC_NULL);
1510:       param->kspmon = PETSC_TRUE;
1511:       PetscPrintf(PETSC_COMM_WORLD,"USER SIGNAL: activating ksp singular value monitor. \n");
1512:     }
1513:   }
1514:   PetscFunctionReturn(SNESDefaultConverged(snes,it,xnorm,pnorm,fnorm,reason,ctx));
1515: }

1517: /* ------------------------------------------------------------------- */
1518: #include <signal.h>
1521: PetscErrorCode InteractiveHandler(int signum, void *ctx)
1522: /* ------------------------------------------------------------------- */
1523: {
1524:   AppCtx    *user = (AppCtx *) ctx;
1525:   Parameter *param = user->param;

1527:   if (signum == SIGILL) {
1528:     param->toggle_kspmon = PETSC_TRUE;
1529:   } else if (signum == SIGCONT) {
1530:     param->interrupted = PETSC_TRUE;
1531:   } else if (signum == SIGURG) {
1532:     param->stop_solve = PETSC_TRUE;
1533:   }
1534:   return 0;
1535: }