Actual source code: ms.c

petsc-master 2019-09-23
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  1:  #include <petsc/private/snesimpl.h>

  3: static SNESMSType SNESMSDefault = SNESMSM62;
  4: static PetscBool  SNESMSRegisterAllCalled;
  5: static PetscBool  SNESMSPackageInitialized;

  7: typedef struct _SNESMSTableau *SNESMSTableau;
  8: struct _SNESMSTableau {
  9:   char      *name;
 10:   PetscInt  nstages;            /* Number of stages */
 11:   PetscInt  nregisters;         /* Number of registers */
 12:   PetscReal stability;          /* Scaled stability region */
 13:   PetscReal *gamma;             /* Coefficients of 3S* method */
 14:   PetscReal *delta;             /* Coefficients of 3S* method */
 15:   PetscReal *betasub;           /* Subdiagonal of beta in Shu-Osher form */
 16: };

 18: typedef struct _SNESMSTableauLink *SNESMSTableauLink;
 19: struct _SNESMSTableauLink {
 20:   struct _SNESMSTableau tab;
 21:   SNESMSTableauLink     next;
 22: };
 23: static SNESMSTableauLink SNESMSTableauList;

 25: typedef struct {
 26:   SNESMSTableau tableau;        /* Tableau in low-storage form */
 27:   PetscReal     damping;        /* Damping parameter, like length of (pseudo) time step */
 28:   PetscBool     norms;          /* Compute norms, usually only for monitoring purposes */
 29: } SNES_MS;

 31: /*@C
 32:   SNESMSRegisterAll - Registers all of the multi-stage methods in SNESMS

 34:   Not Collective, but should be called by all processes which will need the schemes to be registered

 36:   Level: advanced

 38: .seealso:  SNESMSRegisterDestroy()
 39: @*/
 40: PetscErrorCode SNESMSRegisterAll(void)
 41: {

 45:   if (SNESMSRegisterAllCalled) return(0);
 46:   SNESMSRegisterAllCalled = PETSC_TRUE;

 48:   {
 49:     PetscReal gamma[3][1] = {{1.0},{0.0},{0.0}};
 50:     PetscReal delta[1]    = {0.0};
 51:     PetscReal betasub[1]  = {1.0};
 52:     SNESMSRegister(SNESMSEULER,1,3,1.0,&gamma[0][0],delta,betasub);
 53:   }

 55:   {
 56:     PetscReal gamma[3][6] = {
 57:       {0.0000000000000000E+00,  -7.0304722367110606E-01, -1.9836719667506464E-01, -1.6023843981863788E+00, 9.4483822882855284E-02,  -1.4204296130641869E-01},
 58:       {1.0000000000000000E+00,  1.1111025767083920E+00,  5.6150921583923230E-01,  7.4151723494934041E-01,  3.1714538168600587E-01,  4.6479276238548706E-01},
 59:       {0.0000000000000000E+00,  0.0000000000000000E+00,  0.0000000000000000E+00,  6.7968174970583317E-01,  -4.1755042846051737E-03, -1.9115668129923846E-01}
 60:     };
 61:     PetscReal delta[6]   = {1.0000000000000000E+00, 5.3275427433201750E-01, 6.0143544663985238E-01, 4.5874077053842177E-01, 2.7544386906104651E-01, 0.0000000000000000E+00};
 62:     PetscReal betasub[6] = {8.4753115429481929E-01, 7.4018896368655618E-01, 6.5963574086583309E-03, 4.6747795645517759E-01, 1.3314545813643919E-01, 5.3260800028018784E-01};
 63:     SNESMSRegister(SNESMSM62,6,3,1.0,&gamma[0][0],delta,betasub);
 64:   }
 65:   {
 66:     PetscReal gamma[3][4] = {{0,0,0,0},{0,0,0,0},{1,1,1,1}};
 67:     PetscReal delta[4]    = {0,0,0,0};
 68:     PetscReal betasub[4]  = {0.25, 0.5, 0.55, 1.0};
 69:     SNESMSRegister(SNESMSJAMESON83,4,3,1.0,&gamma[0][0],delta,betasub);
 70:   }
 71:   {                             /* Van Leer, Tai, and Powell (1989) 2 stage, order 1 */
 72:     PetscReal gamma[3][2] = {{0,0},{0,0},{1,1}};
 73:     PetscReal delta[2]    = {0,0};
 74:     PetscReal betasub[2]  = {0.3333,1.0};
 75:     SNESMSRegister(SNESMSVLTP21,2,3,1.0,&gamma[0][0],delta,betasub);
 76:   }
 77:   {                             /* Van Leer, Tai, and Powell (1989) 3 stage, order 1 */
 78:     PetscReal gamma[3][3] = {{0,0,0},{0,0,0},{1,1,1}};
 79:     PetscReal delta[3]    = {0,0,0};
 80:     PetscReal betasub[3]  = {0.1481,0.4000,1.0};
 81:     SNESMSRegister(SNESMSVLTP31,3,3,1.5,&gamma[0][0],delta,betasub);
 82:   }
 83:   {                             /* Van Leer, Tai, and Powell (1989) 4 stage, order 1 */
 84:     PetscReal gamma[3][4] = {{0,0,0,0},{0,0,0,0},{1,1,1,1}};
 85:     PetscReal delta[4]    = {0,0,0,0};
 86:     PetscReal betasub[4]  = {0.0833,0.2069,0.4265,1.0};
 87:     SNESMSRegister(SNESMSVLTP41,4,3,2.0,&gamma[0][0],delta,betasub);
 88:   }
 89:   {                             /* Van Leer, Tai, and Powell (1989) 5 stage, order 1 */
 90:     PetscReal gamma[3][5] = {{0,0,0,0,0},{0,0,0,0,0},{1,1,1,1,1}};
 91:     PetscReal delta[5]    = {0,0,0,0,0};
 92:     PetscReal betasub[5]  = {0.0533,0.1263,0.2375,0.4414,1.0};
 93:     SNESMSRegister(SNESMSVLTP51,5,3,2.5,&gamma[0][0],delta,betasub);
 94:   }
 95:   {                             /* Van Leer, Tai, and Powell (1989) 6 stage, order 1 */
 96:     PetscReal gamma[3][6] = {{0,0,0,0,0,0},{0,0,0,0,0,0},{1,1,1,1,1,1}};
 97:     PetscReal delta[6]    = {0,0,0,0,0,0};
 98:     PetscReal betasub[6]  = {0.0370,0.0851,0.1521,0.2562,0.4512,1.0};
 99:     SNESMSRegister(SNESMSVLTP61,6,3,3.0,&gamma[0][0],delta,betasub);
100:   }
101:   return(0);
102: }

104: /*@C
105:    SNESMSRegisterDestroy - Frees the list of schemes that were registered by TSRosWRegister().

107:    Not Collective

109:    Level: advanced

111: .seealso: TSRosWRegister(), TSRosWRegisterAll(), TSRosWRegister()
112: @*/
113: PetscErrorCode SNESMSRegisterDestroy(void)
114: {
115:   PetscErrorCode    ierr;
116:   SNESMSTableauLink link;

119:   while ((link = SNESMSTableauList)) {
120:     SNESMSTableau t = &link->tab;
121:     SNESMSTableauList = link->next;

123:     PetscFree3(t->gamma,t->delta,t->betasub);
124:     PetscFree(t->name);
125:     PetscFree(link);
126:   }
127:   SNESMSRegisterAllCalled = PETSC_FALSE;
128:   return(0);
129: }

131: /*@C
132:   SNESMSInitializePackage - This function initializes everything in the SNESMS package. It is called
133:   from SNESInitializePackage().

135:   Level: developer

137: .seealso: PetscInitialize()
138: @*/
139: PetscErrorCode SNESMSInitializePackage(void)
140: {

144:   if (SNESMSPackageInitialized) return(0);
145:   SNESMSPackageInitialized = PETSC_TRUE;

147:   SNESMSRegisterAll();
148:   PetscRegisterFinalize(SNESMSFinalizePackage);
149:   return(0);
150: }

152: /*@C
153:   SNESMSFinalizePackage - This function destroys everything in the SNESMS package. It is
154:   called from PetscFinalize().

156:   Level: developer

158: .seealso: PetscFinalize()
159: @*/
160: PetscErrorCode SNESMSFinalizePackage(void)
161: {

165:   SNESMSPackageInitialized = PETSC_FALSE;

167:   SNESMSRegisterDestroy();
168:   return(0);
169: }

171: /*@C
172:    SNESMSRegister - register a multistage scheme

174:    Not Collective, but the same schemes should be registered on all processes on which they will be used

176:    Input Parameters:
177: +  name - identifier for method
178: .  nstages - number of stages
179: .  nregisters - number of registers used by low-storage implementation
180: .  gamma - coefficients, see Ketcheson's paper
181: .  delta - coefficients, see Ketcheson's paper
182: -  betasub - subdiagonal of Shu-Osher form

184:    Notes:
185:    The notation is described in Ketcheson (2010) Runge-Kutta methods with minimum storage implementations.

187:    Level: advanced

189: .seealso: SNESMS
190: @*/
191: PetscErrorCode SNESMSRegister(SNESMSType name,PetscInt nstages,PetscInt nregisters,PetscReal stability,const PetscReal gamma[],const PetscReal delta[],const PetscReal betasub[])
192: {
193:   PetscErrorCode    ierr;
194:   SNESMSTableauLink link;
195:   SNESMSTableau     t;

199:   if (nstages < 1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Must have at least one stage");
200:   if (nregisters != 3) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Only support for methods written in 3-register form");

205:   SNESMSInitializePackage();
206:   PetscNew(&link);
207:   t             = &link->tab;
208:   PetscStrallocpy(name,&t->name);
209:   t->nstages    = nstages;
210:   t->nregisters = nregisters;
211:   t->stability  = stability;

213:   PetscMalloc3(nstages*nregisters,&t->gamma,nstages,&t->delta,nstages,&t->betasub);
214:   PetscArraycpy(t->gamma,gamma,nstages*nregisters);
215:   PetscArraycpy(t->delta,delta,nstages);
216:   PetscArraycpy(t->betasub,betasub,nstages);

218:   link->next        = SNESMSTableauList;
219:   SNESMSTableauList = link;
220:   return(0);
221: }

223: /*
224:   X - initial state, updated in-place.
225:   F - residual, computed at the initial X on input
226: */
227: static PetscErrorCode SNESMSStep_3Sstar(SNES snes,Vec X,Vec F)
228: {
229:   PetscErrorCode  ierr;
230:   SNES_MS         *ms    = (SNES_MS*)snes->data;
231:   SNESMSTableau   t      = ms->tableau;
232:   const PetscReal *gamma = t->gamma,*delta = t->delta,*betasub = t->betasub;
233:   Vec             S1,S2,S3,Y;
234:   PetscInt        i,nstages = t->nstages;


238:   Y    = snes->work[0];
239:   S1   = X;
240:   S2   = snes->work[1];
241:   S3   = snes->work[2];
242:   VecZeroEntries(S2);
243:   VecCopy(X,S3);
244:   for (i = 0; i < nstages; i++) {
245:     Vec         Ss[4];
246:     PetscScalar scoeff[4];

248:     Ss[0] = S1; Ss[1] = S2; Ss[2] = S3; Ss[3] = Y;

250:     scoeff[0] = gamma[0*nstages+i] - 1;
251:     scoeff[1] = gamma[1*nstages+i];
252:     scoeff[2] = gamma[2*nstages+i];
253:     scoeff[3] = -betasub[i]*ms->damping;

255:     VecAXPY(S2,delta[i],S1);
256:     if (i > 0) {
257:       SNESComputeFunction(snes,S1,F);
258:     }
259:     KSPSolve(snes->ksp,F,Y);
260:     VecMAXPY(S1,4,scoeff,Ss);
261:   }
262:   return(0);
263: }

265: static PetscErrorCode SNESMSStep_Norms(SNES snes,PetscInt iter,Vec F)
266: {
267:   SNES_MS        *ms = (SNES_MS*)snes->data;
268:   PetscReal      fnorm;

272:   if (ms->norms) {
273:     VecNorm(F,NORM_2,&fnorm); /* fnorm <- ||F||  */
274:     SNESCheckFunctionNorm(snes,fnorm);
275:     /* Monitor convergence */
276:     PetscObjectSAWsTakeAccess((PetscObject)snes);
277:     snes->iter = iter;
278:     snes->norm = fnorm;
279:     PetscObjectSAWsGrantAccess((PetscObject)snes);
280:     SNESLogConvergenceHistory(snes,snes->norm,0);
281:     SNESMonitor(snes,snes->iter,snes->norm);
282:     /* Test for convergence */
283:     (*snes->ops->converged)(snes,snes->iter,0.0,0.0,fnorm,&snes->reason,snes->cnvP);
284:   } else if (iter > 0) {
285:     PetscObjectSAWsTakeAccess((PetscObject)snes);
286:     snes->iter = iter;
287:     PetscObjectSAWsGrantAccess((PetscObject)snes);
288:   }
289:   return(0);
290: }


293: static PetscErrorCode SNESSolve_MS(SNES snes)
294: {
295:   SNES_MS        *ms = (SNES_MS*)snes->data;
296:   Vec            X   = snes->vec_sol,F = snes->vec_func;
297:   PetscInt       i;

301:   if (snes->xl || snes->xu || snes->ops->computevariablebounds) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONGSTATE, "SNES solver %s does not support bounds", ((PetscObject)snes)->type_name);
302:   PetscCitationsRegister(SNESCitation,&SNEScite);

304:   snes->reason = SNES_CONVERGED_ITERATING;
305:   PetscObjectSAWsTakeAccess((PetscObject)snes);
306:   snes->iter   = 0;
307:   snes->norm   = 0;
308:   PetscObjectSAWsGrantAccess((PetscObject)snes);

310:   if (!snes->vec_func_init_set) {
311:     SNESComputeFunction(snes,X,F);
312:   } else snes->vec_func_init_set = PETSC_FALSE;

314:   SNESMSStep_Norms(snes,0,F);
315:   if (snes->reason) return(0);

317:   for (i = 0; i < snes->max_its; i++) {

319:     /* Call general purpose update function */
320:     if (snes->ops->update) {
321:       (*snes->ops->update)(snes,snes->iter);
322:     }

324:     if (i == 0 && snes->jacobian) {
325:       /* This method does not require a Jacobian, but it is usually preconditioned by PBJacobi */
326:       SNESComputeJacobian(snes,snes->vec_sol,snes->jacobian,snes->jacobian_pre);
327:       SNESCheckJacobianDomainerror(snes);
328:       KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);
329:     }

331:     SNESMSStep_3Sstar(snes,X,F);

333:     if (i < snes->max_its-1 || ms->norms) {
334:       SNESComputeFunction(snes,X,F);
335:     }

337:     SNESMSStep_Norms(snes,i+1,F);
338:     if (snes->reason) return(0);
339:   }
340:   if (!snes->reason) snes->reason = SNES_CONVERGED_ITS;
341:   return(0);
342: }

344: static PetscErrorCode SNESSetUp_MS(SNES snes)
345: {
346:   SNES_MS        *ms = (SNES_MS*)snes->data;

350:   if (!ms->tableau) {SNESMSSetType(snes,SNESMSDefault);}
351:   SNESSetWorkVecs(snes,3);
352:   SNESSetUpMatrices(snes);
353:   return(0);
354: }

356: static PetscErrorCode SNESReset_MS(SNES snes)
357: {

360:   return(0);
361: }

363: static PetscErrorCode SNESDestroy_MS(SNES snes)
364: {

368:   SNESReset_MS(snes);
369:   PetscFree(snes->data);
370:   PetscObjectComposeFunction((PetscObject)snes,"SNESMSSetType_C",NULL);
371:   return(0);
372: }

374: static PetscErrorCode SNESView_MS(SNES snes,PetscViewer viewer)
375: {
376:   PetscBool      iascii;
378:   SNES_MS        *ms = (SNES_MS*)snes->data;

381:   PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERASCII, &iascii);
382:   if (iascii) {
383:     SNESMSTableau tab = ms->tableau;
384:     PetscViewerASCIIPrintf(viewer,"  multi-stage method type: %s\n",tab ? tab->name : "not yet set");
385:   }
386:   return(0);
387: }

389: static PetscErrorCode SNESSetFromOptions_MS(PetscOptionItems *PetscOptionsObject,SNES snes)
390: {
391:   SNES_MS        *ms = (SNES_MS*)snes->data;

395:   PetscOptionsHead(PetscOptionsObject,"SNES MS options");
396:   {
397:     SNESMSTableauLink link;
398:     PetscInt          count,choice;
399:     PetscBool         flg;
400:     const char        **namelist;
401:     char              mstype[256];

403:     PetscStrncpy(mstype,SNESMSDefault,sizeof(mstype));
404:     for (link=SNESMSTableauList,count=0; link; link=link->next,count++) ;
405:     PetscMalloc1(count,(char***)&namelist);
406:     for (link=SNESMSTableauList,count=0; link; link=link->next,count++) namelist[count] = link->tab.name;
407:     PetscOptionsEList("-snes_ms_type","Multistage smoother type","SNESMSSetType",(const char*const*)namelist,count,mstype,&choice,&flg);
408:     SNESMSSetType(snes,flg ? namelist[choice] : mstype);
409:     PetscFree(namelist);
410:     PetscOptionsReal("-snes_ms_damping","Damping for multistage method","SNESMSSetDamping",ms->damping,&ms->damping,NULL);
411:     PetscOptionsBool("-snes_ms_norms","Compute norms for monitoring","none",ms->norms,&ms->norms,NULL);
412:   }
413:   PetscOptionsTail();
414:   return(0);
415: }

417: PetscErrorCode  SNESMSSetType_MS(SNES snes,SNESMSType mstype)
418: {
419:   PetscErrorCode    ierr;
420:   SNES_MS           *ms = (SNES_MS*)snes->data;
421:   SNESMSTableauLink link;
422:   PetscBool         match;

425:   if (ms->tableau) {
426:     PetscStrcmp(ms->tableau->name,mstype,&match);
427:     if (match) return(0);
428:   }
429:   for (link = SNESMSTableauList; link; link=link->next) {
430:     PetscStrcmp(link->tab.name,mstype,&match);
431:     if (match) {
432:       SNESReset_MS(snes);
433:       ms->tableau = &link->tab;
434:       return(0);
435:     }
436:   }
437:   SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_UNKNOWN_TYPE,"Could not find '%s'",mstype);
438:   return(0);
439: }

441: /*@C
442:   SNESMSSetType - Set the type of multistage smoother

444:   Logically collective

446:   Input Parameter:
447: +  snes - nonlinear solver context
448: -  mstype - type of multistage method

450:   Level: beginner

452: .seealso: SNESMSGetType(), SNESMS
453: @*/
454: PetscErrorCode SNESMSSetType(SNES snes,SNESMSType rostype)
455: {

460:   PetscTryMethod(snes,"SNESMSSetType_C",(SNES,SNESMSType),(snes,rostype));
461:   return(0);
462: }

464: /* -------------------------------------------------------------------------- */
465: /*MC
466:       SNESMS - multi-stage smoothers

468:       Options Database:

470: +     -snes_ms_type - type of multi-stage smoother
471: -     -snes_ms_damping - damping for multi-stage method

473:       Notes:
474:       These multistage methods are explicit Runge-Kutta methods that are often used as smoothers for
475:       FAS multigrid for transport problems. In the linear case, these are equivalent to polynomial smoothers (such as Chebyshev).

477:       Multi-stage smoothers should usually be preconditioned by point-block Jacobi to ensure proper scaling and to normalize the wave speeds.

479:       The methods are specified in low storage form (Ketcheson 2010). New methods can be registered with SNESMSRegister().

481:       References:
482: +   1. -   Ketcheson (2010) Runge Kutta methods with minimum storage implementations.
483: .   2. -   Jameson (1983) Solution of the Euler equations for two dimensional transonic flow by a multigrid method.
484: -   3. -   Pierce and Giles (1997) Preconditioned multigrid methods for compressible flow calculations on stretched meshes.

486:       Level: beginner

488: .seealso:  SNESCreate(), SNES, SNESSetType(), SNESMS, SNESFAS, KSPCHEBYSHEV

490: M*/
491: PETSC_EXTERN PetscErrorCode SNESCreate_MS(SNES snes)
492: {
494:   SNES_MS        *ms;

497:   SNESMSInitializePackage();

499:   snes->ops->setup          = SNESSetUp_MS;
500:   snes->ops->solve          = SNESSolve_MS;
501:   snes->ops->destroy        = SNESDestroy_MS;
502:   snes->ops->setfromoptions = SNESSetFromOptions_MS;
503:   snes->ops->view           = SNESView_MS;
504:   snes->ops->reset          = SNESReset_MS;

506:   snes->usesnpc = PETSC_FALSE;
507:   snes->usesksp = PETSC_TRUE;

509:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

511:   PetscNewLog(snes,&ms);
512:   snes->data  = (void*)ms;
513:   ms->damping = 0.9;
514:   ms->norms   = PETSC_FALSE;

516:   PetscObjectComposeFunction((PetscObject)snes,"SNESMSSetType_C",SNESMSSetType_MS);
517:   return(0);
518: }