xref: /petsc/src/snes/impls/nasm/nasm.c (revision 0ad7597df3318518cf08ebbaa20b6a237bca446d)
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 
30   PetscFunctionBegin;
31   for (i=0;i<nasm->n;i++) {
32     if (nasm->xl) { ierr = VecDestroy(&nasm->xl[i]);CHKERRQ(ierr); }
33     if (nasm->x) { ierr = VecDestroy(&nasm->x[i]);CHKERRQ(ierr); }
34     if (nasm->y) { ierr = VecDestroy(&nasm->y[i]);CHKERRQ(ierr); }
35     if (nasm->b) { ierr = VecDestroy(&nasm->b[i]);CHKERRQ(ierr); }
36 
37     if (nasm->subsnes) { ierr = SNESDestroy(&nasm->subsnes[i]);CHKERRQ(ierr); }
38     if (nasm->oscatter) { ierr = VecScatterDestroy(&nasm->oscatter[i]);CHKERRQ(ierr); }
39     if (nasm->iscatter) { ierr = VecScatterDestroy(&nasm->iscatter[i]);CHKERRQ(ierr); }
40     if (nasm->gscatter) { ierr = VecScatterDestroy(&nasm->gscatter[i]);CHKERRQ(ierr); }
41   }
42 
43   if (nasm->x) {ierr = PetscFree(nasm->x);CHKERRQ(ierr);}
44   if (nasm->xl) {ierr = PetscFree(nasm->xl);CHKERRQ(ierr);}
45   if (nasm->y) {ierr = PetscFree(nasm->y);CHKERRQ(ierr);}
46   if (nasm->b) {ierr = PetscFree(nasm->b);CHKERRQ(ierr);}
47 
48   if (nasm->subsnes) {ierr = PetscFree(nasm->subsnes);CHKERRQ(ierr);}
49   if (nasm->oscatter) {ierr = PetscFree(nasm->oscatter);CHKERRQ(ierr);}
50   if (nasm->iscatter) {ierr = PetscFree(nasm->iscatter);CHKERRQ(ierr);}
51   if (nasm->gscatter) {ierr = PetscFree(nasm->gscatter);CHKERRQ(ierr);}
52 
53   PetscFunctionReturn(0);
54 }
55 
56 #undef __FUNCT__
57 #define __FUNCT__ "SNESDestroy_NASM"
58 PetscErrorCode SNESDestroy_NASM(SNES snes)
59 {
60   PetscErrorCode ierr;
61 
62   PetscFunctionBegin;
63   ierr = SNESReset_NASM(snes);CHKERRQ(ierr);
64   ierr = PetscFree(snes->data);CHKERRQ(ierr);
65   PetscFunctionReturn(0);
66 }
67 
68 #undef __FUNCT__
69 #define __FUNCT__ "DMGlobalToLocalSubDomainDirichletHook_Private"
70 PetscErrorCode DMGlobalToLocalSubDomainDirichletHook_Private(DM dm,Vec g,InsertMode mode,Vec l,void *ctx)
71 {
72   PetscErrorCode ierr;
73   Vec bcs = (Vec)ctx;
74 
75   PetscFunctionBegin;
76   ierr = VecCopy(bcs,l);CHKERRQ(ierr);
77   PetscFunctionReturn(0);
78 }
79 
80 #undef __FUNCT__
81 #define __FUNCT__ "SNESSetUp_NASM"
82 PetscErrorCode SNESSetUp_NASM(SNES snes)
83 {
84   SNES_NASM      *nasm = (SNES_NASM *)snes->data;
85   PetscErrorCode ierr;
86   DM             dm,ddm;
87   DM             *subdms;
88   PetscInt       i;
89   const char     *optionsprefix;
90   Vec            F;
91 
92   PetscFunctionBegin;
93   if (!nasm->subsnes) {
94     ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
95     if (dm) {
96       nasm->usesdm = PETSC_TRUE;
97       ierr = DMCreateDomainDecomposition(dm,&nasm->n,PETSC_NULL,PETSC_NULL,PETSC_NULL,&subdms);CHKERRQ(ierr);
98       if (!subdms) {
99         ierr = DMCreateDomainDecompositionDM(dm,"default",&ddm);CHKERRQ(ierr);
100         if (!ddm) {
101           SETERRQ(((PetscObject)dm)->comm,PETSC_ERR_ARG_WRONGSTATE,"DM has no default decomposition defined.  Set subsolves manually with SNESNASMSetSubdomains().");
102         }
103         ierr = SNESSetDM(snes,ddm);CHKERRQ(ierr);
104         ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
105         ierr = DMCreateDomainDecomposition(dm,&nasm->n,PETSC_NULL,PETSC_NULL,PETSC_NULL,&subdms);CHKERRQ(ierr);
106       }
107       if (!subdms) {
108         SETERRQ(((PetscObject)dm)->comm,PETSC_ERR_ARG_WRONGSTATE,"DM has no default decomposition defined.  Set subsolves manually with SNESNASMSetSubdomains().");
109       }
110       ierr = DMCreateDomainDecompositionScatters(dm,nasm->n,subdms,&nasm->iscatter,&nasm->oscatter,&nasm->gscatter);CHKERRQ(ierr);
111 
112       ierr = SNESGetOptionsPrefix(snes, &optionsprefix);CHKERRQ(ierr);
113       ierr = PetscMalloc(nasm->n*sizeof(SNES),&nasm->subsnes);CHKERRQ(ierr);
114 
115       for (i=0;i<nasm->n;i++) {
116         ierr = SNESCreate(PETSC_COMM_SELF,&nasm->subsnes[i]);CHKERRQ(ierr);
117         ierr = SNESAppendOptionsPrefix(nasm->subsnes[i],optionsprefix);CHKERRQ(ierr);
118         ierr = SNESAppendOptionsPrefix(nasm->subsnes[i],"sub_");CHKERRQ(ierr);
119         ierr = SNESSetDM(nasm->subsnes[i],subdms[i]);CHKERRQ(ierr);
120         ierr = SNESSetFromOptions(nasm->subsnes[i]);CHKERRQ(ierr);
121         ierr = DMDestroy(&subdms[i]);CHKERRQ(ierr);
122       }
123       ierr = PetscFree(subdms);CHKERRQ(ierr);
124     } else {
125       SETERRQ(((PetscObject)snes)->comm,PETSC_ERR_ARG_WRONGSTATE,"Cannot construct local problems automatically without a DM!");
126     }
127   } else {
128     SETERRQ(((PetscObject)snes)->comm,PETSC_ERR_ARG_WRONGSTATE,"Must set subproblems manually if there is no DM!");
129   }
130   /* allocate the global vectors */
131   ierr = PetscMalloc(nasm->n*sizeof(Vec),&nasm->x);CHKERRQ(ierr);
132   ierr = PetscMalloc(nasm->n*sizeof(Vec),&nasm->xl);CHKERRQ(ierr);
133   ierr = PetscMalloc(nasm->n*sizeof(Vec),&nasm->y);CHKERRQ(ierr);
134   ierr = PetscMalloc(nasm->n*sizeof(Vec),&nasm->b);CHKERRQ(ierr);
135 
136   for (i=0;i<nasm->n;i++) {
137     DM subdm;
138     ierr = SNESGetFunction(nasm->subsnes[i],&F,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
139     ierr = VecDuplicate(F,&nasm->x[i]);CHKERRQ(ierr);
140     ierr = VecDuplicate(F,&nasm->y[i]);CHKERRQ(ierr);
141     ierr = VecDuplicate(F,&nasm->b[i]);CHKERRQ(ierr);
142     ierr = SNESGetDM(nasm->subsnes[i],&subdm);CHKERRQ(ierr);
143     ierr = DMCreateLocalVector(subdm,&nasm->xl[i]);CHKERRQ(ierr);
144     ierr = DMGlobalToLocalHookAdd(subdm,DMGlobalToLocalSubDomainDirichletHook_Private,PETSC_NULL,nasm->xl[i]);CHKERRQ(ierr);
145   }
146 
147   PetscFunctionReturn(0);
148 }
149 
150 #undef __FUNCT__
151 #define __FUNCT__ "SNESSetFromOptions_NASM"
152 PetscErrorCode SNESSetFromOptions_NASM(SNES snes)
153 {
154   PetscErrorCode ierr;
155   DM             dm,ddm;
156   char           ddm_name[1024];
157   PCASMType      asmtype;
158   const char *const SNESNASMTypes[]       = {"NONE","RESTRICT","INTERPOLATE","BASIC","PCASMType","PC_ASM_",0};
159   PetscBool      flg;
160   SNES_NASM      *nasm = (SNES_NASM *)snes->data;
161 
162   PetscFunctionBegin;
163   ierr = PetscOptionsHead("Nonlinear Additive Schwartz options");CHKERRQ(ierr);
164   ierr = PetscOptionsEnum("-snes_nasm_type","Type of restriction/extension","",SNESNASMTypes,(PetscEnum)nasm->type,(PetscEnum*)&asmtype,&flg);CHKERRQ(ierr);
165   if (flg) {nasm->type = asmtype;}
166   ierr = PetscOptionsString("-snes_nasm_decomposition", "Name of the DM defining the composition", "SNESSetDM", ddm_name, ddm_name,1024,&flg);CHKERRQ(ierr);
167   ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
168   if (flg) {
169     if (dm) {
170       ierr = DMCreateDomainDecompositionDM(dm, ddm_name, &ddm);CHKERRQ(ierr);
171       if (!ddm) {
172         SETERRQ1(((PetscObject)snes)->comm, PETSC_ERR_ARG_WRONGSTATE, "Unknown DM decomposition name %s", ddm_name);
173       }
174       ierr = PetscInfo(snes,"Using domain decomposition DM defined using options database\n");CHKERRQ(ierr);
175       ierr = SNESSetDM(snes,ddm);CHKERRQ(ierr);
176     } else {
177       SETERRQ(((PetscObject)snes)->comm, PETSC_ERR_ARG_WRONGSTATE, "No DM to decompose");
178     }
179   }
180   ierr = PetscOptionsTail();CHKERRQ(ierr);
181   PetscFunctionReturn(0);
182 }
183 
184 #undef __FUNCT__
185 #define __FUNCT__ "SNESView_NASM"
186 PetscErrorCode SNESView_NASM(SNES snes, PetscViewer viewer)
187 {
188   PetscFunctionBegin;
189   PetscFunctionReturn(0);
190 }
191 
192 #undef __FUNCT__
193 #define __FUNCT__ "SNESNASMSetSubdomains"
194 PetscErrorCode SNESNASMSetSubdomains(SNES snes,PetscInt n,SNES subsnes[],VecScatter iscatter[],VecScatter oscatter[],VecScatter gscatter[])
195 {
196   PetscErrorCode ierr;
197   PetscErrorCode (*f)(SNES,PetscInt,SNES*,VecScatter*,VecScatter*,VecScatter*);
198 
199   PetscFunctionBegin;
200   ierr = PetscObjectQueryFunction((PetscObject)snes,"SNESNASMSetSubdomains_C",(void (**)(void))&f);CHKERRQ(ierr);
201   ierr = (f)(snes,n,subsnes,iscatter,oscatter,gscatter);CHKERRQ(ierr);
202   PetscFunctionReturn(0);
203 }
204 
205 EXTERN_C_BEGIN
206 #undef __FUNCT__
207 #define __FUNCT__ "SNESNASMSetSubdomains_NASM"
208 PetscErrorCode SNESNASMSetSubdomains_NASM(SNES snes,PetscInt n,SNES subsnes[],VecScatter iscatter[],VecScatter oscatter[],VecScatter gscatter[])
209 {
210   PetscInt       i;
211   PetscErrorCode ierr;
212   SNES_NASM      *nasm = (SNES_NASM *)snes->data;
213 
214   PetscFunctionBegin;
215   if (snes->setupcalled)SETERRQ(((PetscObject)snes)->comm,PETSC_ERR_ARG_WRONGSTATE,"SNESNASMSetSubdomains() should be called before calling SNESSetUp().");
216 
217   /* tear down the previously set things */
218   ierr = SNESReset(snes);CHKERRQ(ierr);
219 
220   nasm->n        = n;
221   if (oscatter) {
222     for (i=0; i<n; i++) {ierr = PetscObjectReference((PetscObject)oscatter[i]);CHKERRQ(ierr);}
223   }
224   if (iscatter) {
225     for (i=0; i<n; i++) {ierr = PetscObjectReference((PetscObject)iscatter[i]);CHKERRQ(ierr);}
226   }
227   if (gscatter) {
228     for (i=0; i<n; i++) {ierr = PetscObjectReference((PetscObject)gscatter[i]);CHKERRQ(ierr);}
229   }
230   if (oscatter) {
231     ierr = PetscMalloc(n*sizeof(IS),&nasm->oscatter);CHKERRQ(ierr);
232     for (i=0; i<n; i++) {
233       nasm->oscatter[i] = oscatter[i];
234     }
235   }
236   if (iscatter) {
237     ierr = PetscMalloc(n*sizeof(IS),&nasm->iscatter);CHKERRQ(ierr);
238     for (i=0; i<n; i++) {
239       nasm->iscatter[i] = iscatter[i];
240     }
241   }
242   if (gscatter) {
243     ierr = PetscMalloc(n*sizeof(IS),&nasm->gscatter);CHKERRQ(ierr);
244     for (i=0; i<n; i++) {
245       nasm->gscatter[i] = gscatter[i];
246     }
247   }
248 
249   if (subsnes) {
250     ierr = PetscMalloc(n*sizeof(SNES),&nasm->subsnes);CHKERRQ(ierr);
251     for (i=0; i<n; i++) {
252       nasm->subsnes[i] = subsnes[i];
253     }
254   }
255   PetscFunctionReturn(0);
256 }
257 EXTERN_C_END
258 
259 #undef __FUNCT__
260 #define __FUNCT__ "SNESNASMSolveLocal_Private"
261 PetscErrorCode SNESNASMSolveLocal_Private(SNES snes,Vec B,Vec Y,Vec X)
262 {
263   SNES_NASM      *nasm = (SNES_NASM *)snes->data;
264   SNES           subsnes;
265   PetscInt       i;
266   PetscErrorCode ierr;
267   Vec            Xlloc,Xl,Bl,Yl;
268   VecScatter     iscat,oscat,gscat;
269   DM             dm,subdm;
270 
271   PetscFunctionBegin;
272   ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
273   ierr = VecSet(Y,0);CHKERRQ(ierr);
274   for (i=0;i<nasm->n;i++) {
275     subsnes = nasm->subsnes[i];
276     ierr = SNESGetDM(subsnes,&subdm);CHKERRQ(ierr);
277     iscat = nasm->iscatter[i];
278     oscat = nasm->oscatter[i];
279     gscat = nasm->gscatter[i];
280     ierr = DMSubDomainRestrict(dm,oscat,gscat,subdm);CHKERRQ(ierr);
281 
282     /* scatter the solution to the local solution */
283     Xl = nasm->x[i];
284     Xlloc = nasm->xl[i];
285     Yl = nasm->y[i];
286 
287     ierr = VecScatterBegin(oscat,X,Xl,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
288     ierr = VecScatterEnd(oscat,X,Xl,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
289 
290     ierr = VecScatterBegin(gscat,X,Xlloc,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
291     ierr = VecScatterEnd(gscat,X,Xlloc,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
292 
293     ierr = VecCopy(Xl,Yl);CHKERRQ(ierr);
294 
295     if (B) {
296       /* scatter the RHS to the local RHS */
297       Bl = nasm->b[i];
298       ierr = VecScatterBegin(oscat,B,Bl,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
299       ierr = VecScatterEnd(oscat,B,Bl,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
300     } else {
301       Bl = PETSC_NULL;
302     }
303     ierr = SNESSolve(subsnes,Bl,Yl);CHKERRQ(ierr);
304 
305     ierr = VecAXPY(Yl,-1.0,Xl);CHKERRQ(ierr);
306 
307     if (nasm->type == PC_ASM_BASIC) {
308       ierr = VecScatterBegin(oscat,Yl,Y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
309       ierr = VecScatterEnd(oscat,Yl,Y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
310     } else if (nasm->type == PC_ASM_RESTRICT) {
311       ierr = VecScatterBegin(iscat,Yl,Y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
312       ierr = VecScatterEnd(iscat,Yl,Y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
313     } else {
314       SETERRQ(((PetscObject)snes)->comm,PETSC_ERR_ARG_WRONGSTATE,"Only basic and interpolate types are supported for SNESNASM");
315     }
316   }
317 
318   ierr = VecAssemblyBegin(Y);CHKERRQ(ierr);
319   ierr = VecAssemblyEnd(Y);CHKERRQ(ierr);
320 
321   ierr = VecAXPY(X,1.0,Y);CHKERRQ(ierr);
322 
323   PetscFunctionReturn(0);
324 }
325 
326 #undef __FUNCT__
327 #define __FUNCT__ "SNESSolve_NASM"
328 PetscErrorCode SNESSolve_NASM(SNES snes)
329 {
330   Vec            F;
331   Vec            X;
332   Vec            B;
333   Vec            Y;
334   PetscInt       i;
335   PetscReal      fnorm;
336   PetscErrorCode ierr;
337   SNESNormType   normtype;
338 
339   PetscFunctionBegin;
340   X = snes->vec_sol;
341   Y = snes->vec_sol_update;
342   F = snes->vec_func;
343   B = snes->vec_rhs;
344 
345   ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr);
346   snes->iter = 0;
347   snes->norm = 0.;
348   ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr);
349   snes->reason = SNES_CONVERGED_ITERATING;
350   ierr = SNESGetNormType(snes, &normtype);CHKERRQ(ierr);
351   if (normtype == SNES_NORM_FUNCTION || normtype == SNES_NORM_INITIAL_ONLY || normtype == SNES_NORM_INITIAL_FINAL_ONLY) {
352     /* compute the initial function and preconditioned update delX */
353     if (!snes->vec_func_init_set) {
354       ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr);
355       if (snes->domainerror) {
356         snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN;
357         PetscFunctionReturn(0);
358       }
359     } else {
360       snes->vec_func_init_set = PETSC_FALSE;
361     }
362 
363     /* convergence test */
364     if (!snes->norm_init_set) {
365       ierr = VecNorm(F, NORM_2, &fnorm);CHKERRQ(ierr); /* fnorm <- ||F||  */
366       if (PetscIsInfOrNanReal(fnorm)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FP,"Infinite or not-a-number generated in norm");
367     } else {
368       fnorm = snes->norm_init;
369       snes->norm_init_set = PETSC_FALSE;
370     }
371     ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr);
372     snes->iter = 0;
373     snes->norm = fnorm;
374     ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr);
375     SNESLogConvHistory(snes,snes->norm,0);
376     ierr = SNESMonitor(snes,0,snes->norm);CHKERRQ(ierr);
377 
378     /* set parameter for default relative tolerance convergence test */
379     snes->ttol = fnorm*snes->rtol;
380 
381     /* test convergence */
382     ierr = (*snes->ops->converged)(snes,0,0.0,0.0,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr);
383     if (snes->reason) PetscFunctionReturn(0);
384   } else {
385     ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr);
386     SNESLogConvHistory(snes,snes->norm,0);
387     ierr = SNESMonitor(snes,0,snes->norm);CHKERRQ(ierr);
388   }
389 
390   /* Call general purpose update function */
391   if (snes->ops->update) {
392     ierr = (*snes->ops->update)(snes, snes->iter);CHKERRQ(ierr);
393   }
394 
395   for (i = 0; i < snes->max_its; i++) {
396     ierr = SNESNASMSolveLocal_Private(snes,B,Y,X);CHKERRQ(ierr);
397     if (normtype == SNES_NORM_FUNCTION || ((i == snes->max_its - 1) && (normtype == SNES_NORM_INITIAL_FINAL_ONLY || normtype == SNES_NORM_FINAL_ONLY))) {
398       ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr);
399       if (snes->domainerror) {
400         snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN;
401         PetscFunctionReturn(0);
402       }
403       ierr = VecNorm(F, NORM_2, &fnorm);CHKERRQ(ierr); /* fnorm <- ||F||  */
404       if (PetscIsInfOrNanReal(fnorm)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FP,"Infinite or not-a-number generated in norm");
405     }
406     /* Monitor convergence */
407     ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr);
408     snes->iter = i+1;
409     snes->norm = fnorm;
410     ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr);
411     SNESLogConvHistory(snes,snes->norm,0);
412     ierr = SNESMonitor(snes,snes->iter,snes->norm);CHKERRQ(ierr);
413     /* Test for convergence */
414     if (normtype == SNES_NORM_FUNCTION) ierr = (*snes->ops->converged)(snes,snes->iter,0.0,0.0,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr);
415     if (snes->reason) PetscFunctionReturn(0);
416     /* Call general purpose update function */
417     if (snes->ops->update) {
418       ierr = (*snes->ops->update)(snes, snes->iter);CHKERRQ(ierr);
419     }
420   }
421   if (normtype == SNES_NORM_FUNCTION) {
422     if (i == snes->max_its) {
423       ierr = PetscInfo1(snes,"Maximum number of iterations has been reached: %D\n",snes->max_its);CHKERRQ(ierr);
424       if (!snes->reason) snes->reason = SNES_DIVERGED_MAX_IT;
425     }
426   } else {
427     if (!snes->reason) snes->reason = SNES_CONVERGED_ITS; /* NASM is meant to be used as a preconditioner */
428   }
429   PetscFunctionReturn(0);
430 }
431 
432 /*MC
433   SNESNASM - Nonlinear Additive Schwartz
434 
435    Level: advanced
436 
437 .seealso: SNESCreate(), SNES, SNESSetType(), SNESType (for list of available types)
438 M*/
439 
440 EXTERN_C_BEGIN
441 #undef __FUNCT__
442 #define __FUNCT__ "SNESCreate_NASM"
443 PetscErrorCode SNESCreate_NASM(SNES snes)
444 {
445   SNES_NASM        *nasm;
446   PetscErrorCode ierr;
447 
448   PetscFunctionBegin;
449   ierr = PetscNewLog(snes, SNES_NASM, &nasm);CHKERRQ(ierr);
450   snes->data = (void*)nasm;
451 
452   nasm->n                 = PETSC_DECIDE;
453   nasm->subsnes           = 0;
454   nasm->x                 = 0;
455   nasm->xl                = 0;
456   nasm->y                 = 0;
457   nasm->b                 = 0;
458   nasm->oscatter          = 0;
459   nasm->iscatter          = 0;
460   nasm->gscatter          = 0;
461 
462   nasm->type              = PC_ASM_BASIC;
463 
464   snes->ops->destroy        = SNESDestroy_NASM;
465   snes->ops->setup          = SNESSetUp_NASM;
466   snes->ops->setfromoptions = SNESSetFromOptions_NASM;
467   snes->ops->view           = SNESView_NASM;
468   snes->ops->solve          = SNESSolve_NASM;
469   snes->ops->reset          = SNESReset_NASM;
470 
471   snes->usesksp             = PETSC_FALSE;
472   snes->usespc              = PETSC_FALSE;
473 
474   if (!snes->tolerancesset) {
475     snes->max_its             = 10000;
476     snes->max_funcs           = 10000;
477   }
478 
479     ierr = PetscObjectComposeFunctionDynamic((PetscObject)snes,"SNESNASMSetSubdomains_C","SNESNASMSetSubdomains_NASM",
480                     SNESNASMSetSubdomains_NASM);CHKERRQ(ierr);
481 
482   PetscFunctionReturn(0);
483 }
484 EXTERN_C_END
485