Actual source code: pcis.c
1: #define PETSCKSP_DLL
3: #include src/ksp/pc/impls/is/pcis.h
5: /* -------------------------------------------------------------------------- */
6: /*
7: PCISSetUp -
8: */
11: PetscErrorCode PETSCKSP_DLLEXPORT PCISSetUp(PC pc)
12: {
13: PC_IS *pcis = (PC_IS*)(pc->data);
14: Mat_IS *matis = (Mat_IS*)pc->mat->data;
15: PetscInt i;
16: PetscErrorCode ierr;
17: PetscTruth flg;
18:
20: PetscTypeCompare((PetscObject)pc->mat,MATIS,&flg);
21: if (!flg){
22: SETERRQ(PETSC_ERR_ARG_WRONG,"Preconditioner type of Neumann Neumman requires matrix of type MATIS");
23: }
25: pcis->pure_neumann = matis->pure_neumann;
27: /*
28: Creating the local vector vec1_N, containing the inverse of the number
29: of subdomains to which each local node (either owned or ghost)
30: pertains. To accomplish that, we scatter local vectors of 1's to
31: a global vector (adding the values); scatter the result back to
32: local vectors and finally invert the result.
33: */
34: {
35: Vec counter;
36: PetscScalar one=1.0, zero=0.0;
37: VecDuplicate(matis->x,&pcis->vec1_N);
38: MatGetVecs(pc->pmat,&counter,0); /* temporary auxiliar vector */
39: VecSet(counter,zero);
40: VecSet(pcis->vec1_N,one);
41: VecScatterBegin(pcis->vec1_N,counter,ADD_VALUES,SCATTER_REVERSE,matis->ctx);
42: VecScatterEnd (pcis->vec1_N,counter,ADD_VALUES,SCATTER_REVERSE,matis->ctx);
43: VecScatterBegin(counter,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD,matis->ctx);
44: VecScatterEnd (counter,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD,matis->ctx);
45: VecDestroy(counter);
46: }
47: /*
48: Creating local and global index sets for interior and
49: inteface nodes. Notice that interior nodes have D[i]==1.0.
50: */
51: {
52: PetscInt n_I;
53: PetscInt *idx_I_local,*idx_B_local,*idx_I_global,*idx_B_global;
54: PetscScalar *array;
55: /* Identifying interior and interface nodes, in local numbering */
56: VecGetSize(pcis->vec1_N,&pcis->n);
57: VecGetArray(pcis->vec1_N,&array);
58: PetscMalloc(pcis->n*sizeof(PetscInt),&idx_I_local);
59: PetscMalloc(pcis->n*sizeof(PetscInt),&idx_B_local);
60: for (i=0, pcis->n_B=0, n_I=0; i<pcis->n; i++) {
61: if (array[i] == 1.0) { idx_I_local[n_I] = i; n_I++; }
62: else { idx_B_local[pcis->n_B] = i; pcis->n_B++; }
63: }
64: /* Getting the global numbering */
65: idx_B_global = idx_I_local + n_I; /* Just avoiding allocating extra memory, since we have vacant space */
66: idx_I_global = idx_B_local + pcis->n_B;
67: ISLocalToGlobalMappingApply(matis->mapping,pcis->n_B,idx_B_local,idx_B_global);
68: ISLocalToGlobalMappingApply(matis->mapping,n_I, idx_I_local,idx_I_global);
69: /* Creating the index sets. */
70: ISCreateGeneral(MPI_COMM_SELF,pcis->n_B,idx_B_local, &pcis->is_B_local);
71: ISCreateGeneral(MPI_COMM_SELF,pcis->n_B,idx_B_global,&pcis->is_B_global);
72: ISCreateGeneral(MPI_COMM_SELF,n_I ,idx_I_local, &pcis->is_I_local);
73: ISCreateGeneral(MPI_COMM_SELF,n_I ,idx_I_global,&pcis->is_I_global);
74: /* Freeing memory and restoring arrays */
75: PetscFree(idx_B_local);
76: PetscFree(idx_I_local);
77: VecRestoreArray(pcis->vec1_N,&array);
78: }
80: /*
81: Extracting the blocks A_II, A_BI, A_IB and A_BB from A. If the numbering
82: is such that interior nodes come first than the interface ones, we have
84: [ | ]
85: [ A_II | A_IB ]
86: A = [ | ]
87: [-----------+------]
88: [ A_BI | A_BB ]
89: */
91: MatGetSubMatrix(matis->A,pcis->is_I_local,pcis->is_I_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_II);
92: MatGetSubMatrix(matis->A,pcis->is_I_local,pcis->is_B_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_IB);
93: MatGetSubMatrix(matis->A,pcis->is_B_local,pcis->is_I_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_BI);
94: MatGetSubMatrix(matis->A,pcis->is_B_local,pcis->is_B_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_BB);
96: /*
97: Creating work vectors and arrays
98: */
99: /* pcis->vec1_N has already been created */
100: VecDuplicate(pcis->vec1_N,&pcis->vec2_N);
101: VecCreateSeq(PETSC_COMM_SELF,pcis->n-pcis->n_B,&pcis->vec1_D);
102: VecDuplicate(pcis->vec1_D,&pcis->vec2_D);
103: VecDuplicate(pcis->vec1_D,&pcis->vec3_D);
104: VecCreateSeq(PETSC_COMM_SELF,pcis->n_B,&pcis->vec1_B);
105: VecDuplicate(pcis->vec1_B,&pcis->vec2_B);
106: VecDuplicate(pcis->vec1_B,&pcis->vec3_B);
107: MatGetVecs(pc->pmat,&pcis->vec1_global,0);
108: PetscMalloc((pcis->n)*sizeof(PetscScalar),&pcis->work_N);
110: /* Creating the scatter contexts */
111: VecScatterCreate(pcis->vec1_global,pcis->is_I_global,pcis->vec1_D,(IS)0,&pcis->global_to_D);
112: VecScatterCreate(pcis->vec1_N,pcis->is_B_local,pcis->vec1_B,(IS)0,&pcis->N_to_B);
113: VecScatterCreate(pcis->vec1_global,pcis->is_B_global,pcis->vec1_B,(IS)0,&pcis->global_to_B);
115: /* Creating scaling "matrix" D, from information in vec1_N */
116: VecDuplicate(pcis->vec1_B,&pcis->D);
117: VecScatterBegin(pcis->vec1_N,pcis->D,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);
118: VecScatterEnd (pcis->vec1_N,pcis->D,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);
119: VecReciprocal(pcis->D);
121: /* See historical note 01, at the bottom of this file. */
123: /*
124: Creating the KSP contexts for the local Dirichlet and Neumann problems.
125: */
126: {
127: PC pc_ctx;
128: /* Dirichlet */
129: KSPCreate(PETSC_COMM_SELF,&pcis->ksp_D);
130: KSPSetOperators(pcis->ksp_D,pcis->A_II,pcis->A_II,SAME_PRECONDITIONER);
131: KSPSetOptionsPrefix(pcis->ksp_D,"is_localD_");
132: KSPGetPC(pcis->ksp_D,&pc_ctx);
133: PCSetType(pc_ctx,PCLU);
134: KSPSetType(pcis->ksp_D,KSPPREONLY);
135: KSPSetFromOptions(pcis->ksp_D);
136: /* the vectors in the following line are dummy arguments, just telling the KSP the vector size. Values are not used */
137: KSPSetUp(pcis->ksp_D);
138: /* Neumann */
139: KSPCreate(PETSC_COMM_SELF,&pcis->ksp_N);
140: KSPSetOperators(pcis->ksp_N,matis->A,matis->A,SAME_PRECONDITIONER);
141: KSPSetOptionsPrefix(pcis->ksp_N,"is_localN_");
142: KSPGetPC(pcis->ksp_N,&pc_ctx);
143: PCSetType(pc_ctx,PCLU);
144: KSPSetType(pcis->ksp_N,KSPPREONLY);
145: KSPSetFromOptions(pcis->ksp_N);
146: {
147: PetscTruth damp_fixed,
148: remove_nullspace_fixed,
149: set_damping_factor_floating,
150: not_damp_floating,
151: not_remove_nullspace_floating;
152: PetscReal fixed_factor,
153: floating_factor;
155: PetscOptionsGetReal(pc_ctx->prefix,"-pc_is_damp_fixed",&fixed_factor,&damp_fixed);
156: if (!damp_fixed) { fixed_factor = 0.0; }
157: PetscOptionsHasName(pc_ctx->prefix,"-pc_is_damp_fixed",&damp_fixed);
159: PetscOptionsHasName(pc_ctx->prefix,"-pc_is_remove_nullspace_fixed",&remove_nullspace_fixed);
161: PetscOptionsGetReal(pc_ctx->prefix,"-pc_is_set_damping_factor_floating",
162: &floating_factor,&set_damping_factor_floating);
163: if (!set_damping_factor_floating) { floating_factor = 0.0; }
164: PetscOptionsHasName(pc_ctx->prefix,"-pc_is_set_damping_factor_floating",&set_damping_factor_floating);
165: if (!set_damping_factor_floating) { floating_factor = 1.e-12; }
167: PetscOptionsHasName(pc_ctx->prefix,"-pc_is_not_damp_floating",¬_damp_floating);
169: PetscOptionsHasName(pc_ctx->prefix,"-pc_is_not_remove_nullspace_floating",¬_remove_nullspace_floating);
171: if (pcis->pure_neumann) { /* floating subdomain */
172: if (!(not_damp_floating)) {
173: PCFactorSetShiftNonzero(pc_ctx,floating_factor);
174: }
175: if (!(not_remove_nullspace_floating)){
176: MatNullSpace nullsp;
177: MatNullSpaceCreate(PETSC_COMM_SELF,PETSC_TRUE,0,PETSC_NULL,&nullsp);
178: KSPSetNullSpace(pcis->ksp_N,nullsp);
179: MatNullSpaceDestroy(nullsp);
180: }
181: } else { /* fixed subdomain */
182: if (damp_fixed) {
183: PCFactorSetShiftNonzero(pc_ctx,fixed_factor);
184: }
185: if (remove_nullspace_fixed) {
186: MatNullSpace nullsp;
187: MatNullSpaceCreate(PETSC_COMM_SELF,PETSC_TRUE,0,PETSC_NULL,&nullsp);
188: KSPSetNullSpace(pcis->ksp_N,nullsp);
189: MatNullSpaceDestroy(nullsp);
190: }
191: }
192: }
193: /* the vectors in the following line are dummy arguments, just telling the KSP the vector size. Values are not used */
194: KSPSetUp(pcis->ksp_N);
195: }
197: ISLocalToGlobalMappingGetInfo(((Mat_IS*)(pc->mat->data))->mapping,&(pcis->n_neigh),&(pcis->neigh),&(pcis->n_shared),&(pcis->shared));
198: pcis->ISLocalToGlobalMappingGetInfoWasCalled = PETSC_TRUE;
199: return(0);
200: }
202: /* -------------------------------------------------------------------------- */
203: /*
204: PCISDestroy -
205: */
208: PetscErrorCode PETSCKSP_DLLEXPORT PCISDestroy(PC pc)
209: {
210: PC_IS *pcis = (PC_IS*)(pc->data);
214: if (pcis->is_B_local) {ISDestroy(pcis->is_B_local);}
215: if (pcis->is_I_local) {ISDestroy(pcis->is_I_local);}
216: if (pcis->is_B_global) {ISDestroy(pcis->is_B_global);}
217: if (pcis->is_I_global) {ISDestroy(pcis->is_I_global);}
218: if (pcis->A_II) {MatDestroy(pcis->A_II);}
219: if (pcis->A_IB) {MatDestroy(pcis->A_IB);}
220: if (pcis->A_BI) {MatDestroy(pcis->A_BI);}
221: if (pcis->A_BB) {MatDestroy(pcis->A_BB);}
222: if (pcis->D) {VecDestroy(pcis->D);}
223: if (pcis->ksp_N) {KSPDestroy(pcis->ksp_N);}
224: if (pcis->ksp_D) {KSPDestroy(pcis->ksp_D);}
225: if (pcis->vec1_N) {VecDestroy(pcis->vec1_N);}
226: if (pcis->vec2_N) {VecDestroy(pcis->vec2_N);}
227: if (pcis->vec1_D) {VecDestroy(pcis->vec1_D);}
228: if (pcis->vec2_D) {VecDestroy(pcis->vec2_D);}
229: if (pcis->vec3_D) {VecDestroy(pcis->vec3_D);}
230: if (pcis->vec1_B) {VecDestroy(pcis->vec1_B);}
231: if (pcis->vec2_B) {VecDestroy(pcis->vec2_B);}
232: if (pcis->vec3_B) {VecDestroy(pcis->vec3_B);}
233: if (pcis->vec1_global) {VecDestroy(pcis->vec1_global);}
234: if (pcis->work_N) {PetscFree(pcis->work_N);}
235: if (pcis->global_to_D) {VecScatterDestroy(pcis->global_to_D);}
236: if (pcis->N_to_B) {VecScatterDestroy(pcis->N_to_B);}
237: if (pcis->global_to_B) {VecScatterDestroy(pcis->global_to_B);}
238: if (pcis->ISLocalToGlobalMappingGetInfoWasCalled) {
239: ISLocalToGlobalMappingRestoreInfo((ISLocalToGlobalMapping)0,&(pcis->n_neigh),&(pcis->neigh),&(pcis->n_shared),&(pcis->shared));
240: }
241: return(0);
242: }
244: /* -------------------------------------------------------------------------- */
245: /*
246: PCISCreate -
247: */
250: PetscErrorCode PETSCKSP_DLLEXPORT PCISCreate(PC pc)
251: {
252: PC_IS *pcis = (PC_IS*)(pc->data);
255: pcis->is_B_local = 0;
256: pcis->is_I_local = 0;
257: pcis->is_B_global = 0;
258: pcis->is_I_global = 0;
259: pcis->A_II = 0;
260: pcis->A_IB = 0;
261: pcis->A_BI = 0;
262: pcis->A_BB = 0;
263: pcis->D = 0;
264: pcis->ksp_N = 0;
265: pcis->ksp_D = 0;
266: pcis->vec1_N = 0;
267: pcis->vec2_N = 0;
268: pcis->vec1_D = 0;
269: pcis->vec2_D = 0;
270: pcis->vec3_D = 0;
271: pcis->vec1_B = 0;
272: pcis->vec2_B = 0;
273: pcis->vec3_B = 0;
274: pcis->vec1_global = 0;
275: pcis->work_N = 0;
276: pcis->global_to_D = 0;
277: pcis->N_to_B = 0;
278: pcis->global_to_B = 0;
279: pcis->ISLocalToGlobalMappingGetInfoWasCalled = PETSC_FALSE;
280: return(0);
281: }
283: /* -------------------------------------------------------------------------- */
284: /*
285: PCISApplySchur -
287: Input parameters:
288: . pc - preconditioner context
289: . v - vector to which the Schur complement is to be applied (it is NOT modified inside this function, UNLESS vec2_B is null)
291: Output parameters:
292: . vec1_B - result of Schur complement applied to chunk
293: . vec2_B - garbage (used as work space), or null (and v is used as workspace)
294: . vec1_D - garbage (used as work space)
295: . vec2_D - garbage (used as work space)
297: */
300: PetscErrorCode PETSCKSP_DLLEXPORT PCISApplySchur(PC pc, Vec v, Vec vec1_B, Vec vec2_B, Vec vec1_D, Vec vec2_D)
301: {
303: PetscScalar m_one = -1.0;
304: PC_IS *pcis = (PC_IS*)(pc->data);
307: if (!vec2_B) { vec2_B = v; }
309: MatMult(pcis->A_BB,v,vec1_B);
310: MatMult(pcis->A_IB,v,vec1_D);
311: KSPSolve(pcis->ksp_D,vec1_D,vec2_D);
312: MatMult(pcis->A_BI,vec2_D,vec2_B);
313: VecAXPY(vec1_B,m_one,vec2_B);
314: return(0);
315: }
317: /* -------------------------------------------------------------------------- */
318: /*
319: PCISScatterArrayNToVecB - Scatters interface node values from a big array (of all local nodes, interior or interface,
320: including ghosts) into an interface vector, when in SCATTER_FORWARD mode, or vice-versa, when in SCATTER_REVERSE
321: mode.
323: Input parameters:
324: . pc - preconditioner context
325: . array_N - [when in SCATTER_FORWARD mode] Array to be scattered into the vector
326: . v_B - [when in SCATTER_REVERSE mode] Vector to be scattered into the array
328: Output parameter:
329: . array_N - [when in SCATTER_REVERSE mode] Array to receive the scattered vector
330: . v_B - [when in SCATTER_FORWARD mode] Vector to receive the scattered array
332: Notes:
333: The entries in the array that do not correspond to interface nodes remain unaltered.
334: */
337: PetscErrorCode PETSCKSP_DLLEXPORT PCISScatterArrayNToVecB (PetscScalar *array_N, Vec v_B, InsertMode imode, ScatterMode smode, PC pc)
338: {
339: PetscInt i, *idex;
341: PetscScalar *array_B;
342: PC_IS *pcis = (PC_IS*)(pc->data);
345: VecGetArray(v_B,&array_B);
346: ISGetIndices(pcis->is_B_local,&idex);
348: if (smode == SCATTER_FORWARD) {
349: if (imode == INSERT_VALUES) {
350: for (i=0; i<pcis->n_B; i++) { array_B[i] = array_N[idex[i]]; }
351: } else { /* ADD_VALUES */
352: for (i=0; i<pcis->n_B; i++) { array_B[i] += array_N[idex[i]]; }
353: }
354: } else { /* SCATTER_REVERSE */
355: if (imode == INSERT_VALUES) {
356: for (i=0; i<pcis->n_B; i++) { array_N[idex[i]] = array_B[i]; }
357: } else { /* ADD_VALUES */
358: for (i=0; i<pcis->n_B; i++) { array_N[idex[i]] += array_B[i]; }
359: }
360: }
361: ISRestoreIndices(pcis->is_B_local,&idex);
362: VecRestoreArray(v_B,&array_B);
363: return(0);
364: }
366: /* -------------------------------------------------------------------------- */
367: /*
368: PCISApplyInvSchur - Solves the Neumann problem related to applying the inverse of the Schur complement.
369: More precisely, solves the problem:
370: [ A_II A_IB ] [ . ] [ 0 ]
371: [ ] [ ] = [ ]
372: [ A_BI A_BB ] [ x ] [ b ]
374: Input parameters:
375: . pc - preconditioner context
376: . b - vector of local interface nodes (including ghosts)
378: Output parameters:
379: . x - vector of local interface nodes (including ghosts); returns the application of the inverse of the Schur
380: complement to b
381: . vec1_N - vector of local nodes (interior and interface, including ghosts); returns garbage (used as work space)
382: . vec2_N - vector of local nodes (interior and interface, including ghosts); returns garbage (used as work space)
384: */
387: PetscErrorCode PETSCKSP_DLLEXPORT PCISApplyInvSchur (PC pc, Vec b, Vec x, Vec vec1_N, Vec vec2_N)
388: {
390: PC_IS *pcis = (PC_IS*)(pc->data);
391: PetscScalar zero = 0.0;
394: /*
395: Neumann solvers.
396: Applying the inverse of the local Schur complement, i.e, solving a Neumann
397: Problem with zero at the interior nodes of the RHS and extracting the interface
398: part of the solution. inverse Schur complement is applied to b and the result
399: is stored in x.
400: */
401: /* Setting the RHS vec1_N */
402: VecSet(vec1_N,zero);
403: VecScatterBegin(b,vec1_N,INSERT_VALUES,SCATTER_REVERSE,pcis->N_to_B);
404: VecScatterEnd (b,vec1_N,INSERT_VALUES,SCATTER_REVERSE,pcis->N_to_B);
405: /* Checking for consistency of the RHS */
406: {
407: PetscTruth flg;
408: PetscOptionsHasName(PETSC_NULL,"-pc_is_check_consistency",&flg);
409: if (flg) {
410: PetscScalar average;
411: VecSum(vec1_N,&average);
412: average = average / ((PetscReal)pcis->n);
413: if (pcis->pure_neumann) {
414: PetscViewerASCIISynchronizedPrintf(PETSC_VIEWER_STDOUT_(pc->comm),"Subdomain %04d is floating. Average = % 1.14e\n",
415: PetscGlobalRank,PetscAbsScalar(average));
416: } else {
417: PetscViewerASCIISynchronizedPrintf(PETSC_VIEWER_STDOUT_(pc->comm),"Subdomain %04d is fixed. Average = % 1.14e\n",
418: PetscGlobalRank,PetscAbsScalar(average));
419: }
420: PetscViewerFlush(PETSC_VIEWER_STDOUT_(pc->comm));
421: }
422: }
423: /* Solving the system for vec2_N */
424: KSPSolve(pcis->ksp_N,vec1_N,vec2_N);
425: /* Extracting the local interface vector out of the solution */
426: VecScatterBegin(vec2_N,x,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);
427: VecScatterEnd (vec2_N,x,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);
428: return(0);
429: }