xref: /petsc/src/snes/impls/nasm/nasm.c (revision 18e2ec274b9e92144f2ef650b9690aa28f9a6737)
1 #include <petsc-private/snesimpl.h>             /*I   "petscsnes.h"   I*/
2 #include <petscdm.h>
3 
4 typedef struct {
5   PetscInt   n;                   /* local subdomains */
6   SNES       *subsnes;            /* nonlinear solvers for each subdomain */
7 
8   Vec        *x;                  /* solution vectors */
9   Vec        *xl;                 /* solution local vectors */
10   Vec        *y;                  /* step vectors */
11   Vec        *b;                  /* rhs vectors */
12 
13   VecScatter *oscatter;           /* scatter from global space to the subdomain global space */
14   VecScatter *iscatter;           /* scatter from global space to the nonoverlapping subdomain space */
15   VecScatter *gscatter;           /* scatter from global space to the subdomain local space */
16 
17   PCASMType type;                 /* ASM type */
18 
19   PetscBool  usesdm;               /* use the DM for setting up the subproblems */
20 } SNES_NASM;
21 
22 #undef __FUNCT__
23 #define __FUNCT__ "SNESReset_NASM"
24 PetscErrorCode SNESReset_NASM(SNES snes)
25 {
26   SNES_NASM      *nasm = (SNES_NASM *)snes->data;
27   PetscErrorCode ierr;
28   PetscInt       i;
29   PetscFunctionBegin;
30   for (i=0;i<nasm->n;i++) {
31     if (nasm->x) { ierr = VecDestroy(&nasm->x[i]);CHKERRQ(ierr); }
32     if (nasm->xl){ ierr = VecDestroy(&nasm->xl[i]);CHKERRQ(ierr); }
33     if (nasm->y) { ierr = VecDestroy(&nasm->y[i]);CHKERRQ(ierr); }
34     if (nasm->b) { ierr = VecDestroy(&nasm->b[i]);CHKERRQ(ierr); }
35 
36     if (nasm->subsnes) { ierr = SNESDestroy(&nasm->subsnes[i]);CHKERRQ(ierr); }
37     if (nasm->oscatter) { ierr = VecScatterDestroy(&nasm->oscatter[i]);CHKERRQ(ierr); }
38     if (nasm->iscatter) { ierr = VecScatterDestroy(&nasm->iscatter[i]);CHKERRQ(ierr); }
39     if (nasm->gscatter) { ierr = VecScatterDestroy(&nasm->gscatter[i]);CHKERRQ(ierr); }
40   }
41 
42   if (nasm->x) {ierr = PetscFree(nasm->x);CHKERRQ(ierr);}
43   if (nasm->xl) {ierr = PetscFree(nasm->xl);CHKERRQ(ierr);}
44   if (nasm->y) {ierr = PetscFree(nasm->y);CHKERRQ(ierr);}
45   if (nasm->b) {ierr = PetscFree(nasm->b);CHKERRQ(ierr);}
46 
47   if (nasm->subsnes) {ierr = PetscFree(nasm->subsnes);CHKERRQ(ierr);}
48   if (nasm->oscatter) {ierr = PetscFree(nasm->oscatter);CHKERRQ(ierr);}
49   if (nasm->iscatter) {ierr = PetscFree(nasm->iscatter);CHKERRQ(ierr);}
50   if (nasm->gscatter) {ierr = PetscFree(nasm->gscatter);CHKERRQ(ierr);}
51 
52   PetscFunctionReturn(0);
53 }
54 
55 #undef __FUNCT__
56 #define __FUNCT__ "SNESDestroy_NASM"
57 PetscErrorCode SNESDestroy_NASM(SNES snes)
58 {
59   PetscErrorCode ierr;
60   PetscFunctionBegin;
61   ierr = SNESReset_NASM(snes);CHKERRQ(ierr);
62   ierr = PetscFree(snes->data);CHKERRQ(ierr);
63   PetscFunctionReturn(0);
64 }
65 
66 #undef __FUNCT__
67 #define __FUNCT__ "DMGlobalToLocalSubDomainDirichletHook_Private"
68 PetscErrorCode DMGlobalToLocalSubDomainDirichletHook_Private(DM dm,Vec g,InsertMode mode,Vec l,void *ctx) {
69   PetscErrorCode ierr;
70   Vec bcs = (Vec)ctx;
71   PetscFunctionBegin;
72   ierr = VecCopy(bcs,l);CHKERRQ(ierr);
73   PetscFunctionReturn(0);
74 }
75 
76 #undef __FUNCT__
77 #define __FUNCT__ "SNESSetUp_NASM"
78 PetscErrorCode SNESSetUp_NASM(SNES snes)
79 {
80   SNES_NASM      *nasm = (SNES_NASM *)snes->data;
81   PetscErrorCode ierr;
82   DM             dm,ddm;
83   DM             *subdms;
84   PetscInt       i;
85   const char     *optionsprefix;
86   Vec            F;
87 
88   PetscFunctionBegin;
89 
90   if (!nasm->subsnes) {
91     ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
92     if (dm) {
93       nasm->usesdm = PETSC_TRUE;
94       ierr = DMCreateDomainDecomposition(dm,&nasm->n,PETSC_NULL,PETSC_NULL,PETSC_NULL,&subdms);CHKERRQ(ierr);
95       if (!subdms) {
96         ierr = DMCreateDomainDecompositionDM(dm,"default",&ddm);CHKERRQ(ierr);
97         if (!ddm) {
98           SETERRQ(((PetscObject)dm)->comm,PETSC_ERR_ARG_WRONGSTATE,"DM has no default decomposition defined.  Set subsolves manually with SNESNASMSetSubdomains().");
99         }
100         ierr = SNESSetDM(snes,ddm);CHKERRQ(ierr);
101         ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
102         ierr = DMCreateDomainDecomposition(dm,&nasm->n,PETSC_NULL,PETSC_NULL,PETSC_NULL,&subdms);CHKERRQ(ierr);
103       }
104       if (!subdms) {
105         SETERRQ(((PetscObject)dm)->comm,PETSC_ERR_ARG_WRONGSTATE,"DM has no default decomposition defined.  Set subsolves manually with SNESNASMSetSubdomains().");
106       }
107       ierr = DMCreateDomainDecompositionScatters(dm,nasm->n,subdms,&nasm->iscatter,&nasm->oscatter,&nasm->gscatter);CHKERRQ(ierr);
108 
109       ierr = SNESGetOptionsPrefix(snes, &optionsprefix);CHKERRQ(ierr);
110       ierr = PetscMalloc(nasm->n*sizeof(SNES),&nasm->subsnes);CHKERRQ(ierr);
111 
112       for (i=0;i<nasm->n;i++) {
113         ierr = SNESCreate(PETSC_COMM_SELF,&nasm->subsnes[i]);CHKERRQ(ierr);
114         ierr = SNESAppendOptionsPrefix(nasm->subsnes[i],optionsprefix);CHKERRQ(ierr);
115         ierr = SNESAppendOptionsPrefix(nasm->subsnes[i],"sub_");CHKERRQ(ierr);
116         ierr = SNESSetDM(nasm->subsnes[i],subdms[i]);CHKERRQ(ierr);
117         ierr = SNESSetFromOptions(nasm->subsnes[i]);CHKERRQ(ierr);
118         ierr = DMDestroy(&subdms[i]);CHKERRQ(ierr);
119       }
120       ierr = PetscFree(subdms);CHKERRQ(ierr);
121     } else {
122       SETERRQ(((PetscObject)snes)->comm,PETSC_ERR_ARG_WRONGSTATE,"Cannot construct local problems automatically without a DM!");
123     }
124   } else {
125     SETERRQ(((PetscObject)snes)->comm,PETSC_ERR_ARG_WRONGSTATE,"Must set subproblems manually if there is no DM!");
126   }
127   /* allocate the global vectors */
128   ierr = PetscMalloc(nasm->n*sizeof(Vec),&nasm->x);CHKERRQ(ierr);
129   ierr = PetscMalloc(nasm->n*sizeof(Vec),&nasm->xl);CHKERRQ(ierr);
130   ierr = PetscMalloc(nasm->n*sizeof(Vec),&nasm->y);CHKERRQ(ierr);
131   ierr = PetscMalloc(nasm->n*sizeof(Vec),&nasm->b);CHKERRQ(ierr);
132 
133   for (i=0;i<nasm->n;i++) {
134     DM subdm;
135     ierr = SNESGetFunction(nasm->subsnes[i],&F,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
136     ierr = VecDuplicate(F,&nasm->x[i]);CHKERRQ(ierr);
137     ierr = VecDuplicate(F,&nasm->y[i]);CHKERRQ(ierr);
138     ierr = VecDuplicate(F,&nasm->b[i]);CHKERRQ(ierr);
139     ierr = SNESGetDM(nasm->subsnes[i],&subdm);CHKERRQ(ierr);
140     ierr = DMCreateLocalVector(subdm,&nasm->xl[i]);CHKERRQ(ierr);
141     ierr = DMGlobalToLocalHookAdd(subdm,DMGlobalToLocalSubDomainDirichletHook_Private,PETSC_NULL,nasm->xl[i]);CHKERRQ(ierr);
142   }
143 
144   PetscFunctionReturn(0);
145 }
146 
147 #undef __FUNCT__
148 #define __FUNCT__ "SNESSetFromOptions_NASM"
149 PetscErrorCode SNESSetFromOptions_NASM(SNES snes)
150 {
151   PetscErrorCode ierr;
152   DM             dm,ddm;
153   char           ddm_name[1024];
154   PCASMType      asmtype;
155   const char *const SNESNASMTypes[]       = {"NONE","RESTRICT","INTERPOLATE","BASIC","PCASMType","PC_ASM_",0};
156   PetscBool      flg;
157   SNES_NASM      *nasm = (SNES_NASM *)snes->data;
158   PetscFunctionBegin;
159   ierr = PetscOptionsHead("Nonlinear Additive Schwartz options");CHKERRQ(ierr);
160   ierr = PetscOptionsEnum("-snes_nasm_type","Type of restriction/extension","",SNESNASMTypes,(PetscEnum)nasm->type,(PetscEnum*)&asmtype,&flg);CHKERRQ(ierr);
161   if (flg) {nasm->type = asmtype;}
162   ierr = PetscOptionsString("-snes_nasm_decomposition", "Name of the DM defining the composition", "SNESSetDM", ddm_name, ddm_name,1024,&flg);CHKERRQ(ierr);
163   ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
164   if (flg) {
165     if (dm) {
166       ierr = DMCreateDomainDecompositionDM(dm, ddm_name, &ddm);CHKERRQ(ierr);
167       if (!ddm) {
168         SETERRQ1(((PetscObject)snes)->comm, PETSC_ERR_ARG_WRONGSTATE, "Unknown DM decomposition name %s", ddm_name);
169       }
170       ierr = PetscInfo(snes,"Using domain decomposition DM defined using options database\n");CHKERRQ(ierr);
171       ierr = SNESSetDM(snes,ddm);CHKERRQ(ierr);
172     } else {
173       SETERRQ(((PetscObject)snes)->comm, PETSC_ERR_ARG_WRONGSTATE, "No DM to decompose");
174     }
175   }
176   ierr = PetscOptionsTail();CHKERRQ(ierr);
177   PetscFunctionReturn(0);
178 }
179 
180 #undef __FUNCT__
181 #define __FUNCT__ "SNESView_NASM"
182 PetscErrorCode SNESView_NASM(SNES snes, PetscViewer viewer)
183 {
184   PetscFunctionBegin;
185 
186 
187   PetscFunctionReturn(0);
188 }
189 
190 #undef __FUNCT__
191 #define __FUNCT__ "SNESNASMSetSubdomains"
192 PetscErrorCode SNESNASMSetSubdomains(SNES snes,PetscInt n,SNES subsnes[],VecScatter iscatter[],VecScatter oscatter[],VecScatter gscatter[]) {
193   PetscErrorCode ierr;
194   PetscErrorCode (*f)(SNES,PetscInt,SNES*,VecScatter*,VecScatter*,VecScatter*);
195   PetscFunctionBegin;
196   ierr = PetscObjectQueryFunction((PetscObject)snes,"SNESNASMSetSubdomains_C",(void (**)(void))&f);CHKERRQ(ierr);
197   ierr = (f)(snes,n,subsnes,iscatter,oscatter,gscatter);CHKERRQ(ierr);
198   PetscFunctionReturn(0);
199 }
200 
201 EXTERN_C_BEGIN
202 #undef __FUNCT__
203 #define __FUNCT__ "SNESNASMSetSubdomains_NASM"
204 PetscErrorCode SNESNASMSetSubdomains_NASM(SNES snes,PetscInt n,SNES subsnes[],VecScatter iscatter[],VecScatter oscatter[],VecScatter gscatter[]) {
205   PetscInt       i;
206   PetscErrorCode ierr;
207   SNES_NASM      *nasm = (SNES_NASM *)snes->data;
208   PetscFunctionBegin;
209   if (snes->setupcalled)SETERRQ(((PetscObject)snes)->comm,PETSC_ERR_ARG_WRONGSTATE,"SNESNASMSetSubdomains() should be called before calling SNESSetUp().");
210 
211   /* tear down the previously set things */
212   ierr = SNESReset(snes);CHKERRQ(ierr);
213 
214   nasm->n        = n;
215   if (oscatter) {
216     for (i=0; i<n; i++) {ierr = PetscObjectReference((PetscObject)oscatter[i]);CHKERRQ(ierr);}
217   }
218   if (iscatter) {
219     for (i=0; i<n; i++) {ierr = PetscObjectReference((PetscObject)iscatter[i]);CHKERRQ(ierr);}
220   }
221   if (gscatter) {
222     for (i=0; i<n; i++) {ierr = PetscObjectReference((PetscObject)gscatter[i]);CHKERRQ(ierr);}
223   }
224   if (oscatter) {
225     ierr = PetscMalloc(n*sizeof(IS),&nasm->oscatter);CHKERRQ(ierr);
226     for (i=0; i<n; i++) {
227       nasm->oscatter[i] = oscatter[i];
228     }
229   }
230   if (iscatter) {
231     ierr = PetscMalloc(n*sizeof(IS),&nasm->iscatter);CHKERRQ(ierr);
232     for (i=0; i<n; i++) {
233       nasm->iscatter[i] = iscatter[i];
234     }
235   }
236   if (gscatter) {
237     ierr = PetscMalloc(n*sizeof(IS),&nasm->gscatter);CHKERRQ(ierr);
238     for (i=0; i<n; i++) {
239       nasm->gscatter[i] = gscatter[i];
240     }
241   }
242 
243   if (subsnes) {
244     ierr = PetscMalloc(n*sizeof(SNES),&nasm->subsnes);CHKERRQ(ierr);
245     for (i=0; i<n; i++) {
246       nasm->subsnes[i] = subsnes[i];
247     }
248   }
249   PetscFunctionReturn(0);
250 }
251 EXTERN_C_END
252 
253 #undef __FUNCT__
254 #define __FUNCT__ "SNESNASMSolveLocal_Private"
255 PetscErrorCode SNESNASMSolveLocal_Private(SNES snes,Vec B,Vec Y,Vec X) {
256   SNES_NASM      *nasm = (SNES_NASM *)snes->data;
257   SNES           subsnes;
258   PetscInt       i;
259   PetscErrorCode ierr;
260   Vec            Xlloc,Xl,Bl,Yl;
261   VecScatter     iscat,oscat,gscat;
262   DM             dm,subdm;
263   PetscFunctionBegin;
264   ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
265   ierr = VecSet(Y,0);CHKERRQ(ierr);
266   for(i=0;i<nasm->n;i++) {
267     subsnes = nasm->subsnes[i];
268     ierr = SNESGetDM(subsnes,&subdm);CHKERRQ(ierr);
269     iscat = nasm->iscatter[i];
270     oscat = nasm->oscatter[i];
271     gscat = nasm->gscatter[i];
272     ierr = DMSubDomainRestrict(dm,oscat,gscat,subdm);CHKERRQ(ierr);
273 
274     /* scatter the solution to the local solution */
275     Xl = nasm->x[i];
276     Xlloc = nasm->xl[i];
277     Yl = nasm->y[i];
278 
279     ierr = VecScatterBegin(oscat,X,Xl,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
280     ierr = VecScatterEnd(oscat,X,Xl,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
281 
282     ierr = VecScatterBegin(gscat,X,Xlloc,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
283     ierr = VecScatterEnd(gscat,X,Xlloc,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
284 
285     ierr = VecCopy(Xl,Yl);CHKERRQ(ierr);
286 
287     if (B) {
288       /* scatter the RHS to the local RHS */
289       Bl = nasm->b[i];
290       ierr = VecScatterBegin(oscat,B,Bl,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
291       ierr = VecScatterEnd(oscat,B,Bl,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
292     } else {
293       Bl = PETSC_NULL;
294     }
295     ierr = SNESSolve(subsnes,Bl,Yl);CHKERRQ(ierr);
296 
297     ierr = VecAXPY(Yl,-1.0,Xl);CHKERRQ(ierr);
298 
299     if (nasm->type == PC_ASM_BASIC) {
300       ierr = VecScatterBegin(oscat,Yl,Y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
301       ierr = VecScatterEnd(oscat,Yl,Y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
302     } else if (nasm->type == PC_ASM_RESTRICT) {
303       ierr = VecScatterBegin(iscat,Yl,Y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
304       ierr = VecScatterEnd(iscat,Yl,Y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
305     } else {
306       SETERRQ(((PetscObject)snes)->comm,PETSC_ERR_ARG_WRONGSTATE,"Only basic and interpolate types are supported for SNESNASM");
307     }
308   }
309 
310   ierr = VecAssemblyBegin(Y);CHKERRQ(ierr);
311   ierr = VecAssemblyEnd(Y);CHKERRQ(ierr);
312 
313   ierr = VecAXPY(X,1.0,Y);CHKERRQ(ierr);
314 
315   PetscFunctionReturn(0);
316 }
317 
318 #undef __FUNCT__
319 #define __FUNCT__ "SNESSolve_NASM"
320 PetscErrorCode SNESSolve_NASM(SNES snes)
321 {
322   Vec            F;
323   Vec            X;
324   Vec            B;
325   Vec            Y;
326   PetscInt       i;
327   PetscReal      fnorm;
328   PetscErrorCode ierr;
329   SNESNormType   normtype;
330 
331   PetscFunctionBegin;
332 
333   X = snes->vec_sol;
334   Y = snes->vec_sol_update;
335   F = snes->vec_func;
336   B = snes->vec_rhs;
337 
338   ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr);
339   snes->iter = 0;
340   snes->norm = 0.;
341   ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr);
342   snes->reason = SNES_CONVERGED_ITERATING;
343   ierr = SNESGetNormType(snes, &normtype);CHKERRQ(ierr);
344   if (normtype == SNES_NORM_FUNCTION || normtype == SNES_NORM_INITIAL_ONLY || normtype == SNES_NORM_INITIAL_FINAL_ONLY) {
345     /* compute the initial function and preconditioned update delX */
346     if (!snes->vec_func_init_set) {
347       ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr);
348       if (snes->domainerror) {
349         snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN;
350         PetscFunctionReturn(0);
351       }
352     } else {
353       snes->vec_func_init_set = PETSC_FALSE;
354     }
355 
356     /* convergence test */
357     if (!snes->norm_init_set) {
358       ierr = VecNorm(F, NORM_2, &fnorm);CHKERRQ(ierr); /* fnorm <- ||F||  */
359       if (PetscIsInfOrNanReal(fnorm)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FP,"Infinite or not-a-number generated in norm");
360     } else {
361       fnorm = snes->norm_init;
362       snes->norm_init_set = PETSC_FALSE;
363     }
364     ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr);
365     snes->iter = 0;
366     snes->norm = fnorm;
367     ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr);
368     SNESLogConvHistory(snes,snes->norm,0);
369     ierr = SNESMonitor(snes,0,snes->norm);CHKERRQ(ierr);
370 
371     /* set parameter for default relative tolerance convergence test */
372     snes->ttol = fnorm*snes->rtol;
373 
374     /* test convergence */
375     ierr = (*snes->ops->converged)(snes,0,0.0,0.0,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr);
376     if (snes->reason) PetscFunctionReturn(0);
377   } else {
378     ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr);
379     SNESLogConvHistory(snes,snes->norm,0);
380     ierr = SNESMonitor(snes,0,snes->norm);CHKERRQ(ierr);
381   }
382 
383   /* Call general purpose update function */
384   if (snes->ops->update) {
385     ierr = (*snes->ops->update)(snes, snes->iter);CHKERRQ(ierr);
386   }
387 
388   for (i = 0; i < snes->max_its; i++) {
389     ierr = SNESNASMSolveLocal_Private(snes,B,Y,X);CHKERRQ(ierr);
390     if (normtype == SNES_NORM_FUNCTION || ((i == snes->max_its - 1) && (normtype == SNES_NORM_INITIAL_FINAL_ONLY || normtype == SNES_NORM_FINAL_ONLY))) {
391       ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr);
392       if (snes->domainerror) {
393         snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN;
394         PetscFunctionReturn(0);
395       }
396       ierr = VecNorm(F, NORM_2, &fnorm);CHKERRQ(ierr); /* fnorm <- ||F||  */
397       if (PetscIsInfOrNanReal(fnorm)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FP,"Infinite or not-a-number generated in norm");
398     }
399     /* Monitor convergence */
400     ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr);
401     snes->iter = i+1;
402     snes->norm = fnorm;
403     ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr);
404     SNESLogConvHistory(snes,snes->norm,0);
405     ierr = SNESMonitor(snes,snes->iter,snes->norm);CHKERRQ(ierr);
406     /* Test for convergence */
407     if (normtype == SNES_NORM_FUNCTION) ierr = (*snes->ops->converged)(snes,snes->iter,0.0,0.0,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr);
408     if (snes->reason) PetscFunctionReturn(0);
409     /* Call general purpose update function */
410     if (snes->ops->update) {
411       ierr = (*snes->ops->update)(snes, snes->iter);CHKERRQ(ierr);
412     }
413   }
414   if (normtype == SNES_NORM_FUNCTION) {
415     if (i == snes->max_its) {
416       ierr = PetscInfo1(snes,"Maximum number of iterations has been reached: %D\n",snes->max_its);CHKERRQ(ierr);
417       if(!snes->reason) snes->reason = SNES_DIVERGED_MAX_IT;
418     }
419   } else {
420     if (!snes->reason) snes->reason = SNES_CONVERGED_ITS; /* NASM is meant to be used as a preconditioner */
421   }
422   PetscFunctionReturn(0);
423 }
424 
425 /*MC
426   SNESNASM - Nonlinear Additive Schwartz
427 
428    Level: advanced
429 
430 .seealso: SNESCreate(), SNES, SNESSetType(), SNESType (for list of available types)
431 M*/
432 
433 EXTERN_C_BEGIN
434 #undef __FUNCT__
435 #define __FUNCT__ "SNESCreate_NASM"
436 PetscErrorCode SNESCreate_NASM(SNES snes)
437 {
438   SNES_NASM        *nasm;
439   PetscErrorCode ierr;
440 
441   PetscFunctionBegin;
442 
443 
444   ierr = PetscNewLog(snes, SNES_NASM, &nasm);CHKERRQ(ierr);
445   snes->data = (void*)nasm;
446 
447   nasm->n                 = PETSC_DECIDE;
448   nasm->subsnes           = 0;
449   nasm->x                 = 0;
450   nasm->xl                = 0;
451   nasm->y                 = 0;
452   nasm->b                 = 0;
453   nasm->oscatter          = 0;
454   nasm->iscatter          = 0;
455   nasm->gscatter          = 0;
456 
457   nasm->type              = PC_ASM_BASIC;
458 
459   snes->ops->destroy        = SNESDestroy_NASM;
460   snes->ops->setup          = SNESSetUp_NASM;
461   snes->ops->setfromoptions = SNESSetFromOptions_NASM;
462   snes->ops->view           = SNESView_NASM;
463   snes->ops->solve          = SNESSolve_NASM;
464   snes->ops->reset          = SNESReset_NASM;
465 
466   snes->usesksp             = PETSC_FALSE;
467   snes->usespc              = PETSC_FALSE;
468 
469   if (!snes->tolerancesset) {
470     snes->max_its             = 10000;
471     snes->max_funcs           = 10000;
472   }
473 
474     ierr = PetscObjectComposeFunctionDynamic((PetscObject)snes,"SNESNASMSetSubdomains_C","SNESNASMSetSubdomains_NASM",
475                     SNESNASMSetSubdomains_NASM);CHKERRQ(ierr);
476 
477   PetscFunctionReturn(0);
478 }
479 EXTERN_C_END
480