Actual source code: is.c
1: /*$Id: is.c,v 1.7 2001/03/23 23:23:21 balay Exp $*/
2: #include src/sles/pc/impls/is/is.h
4: /* -------------------------------------------------------------------------- */
5: /*
6: PCISSetUp -
7: */
8: int PCISSetUp(PC pc)
9: {
10: PC_IS *pcis = (PC_IS*)(pc->data);
11: Mat_IS *matis = (Mat_IS*)pc->mat->data;
12: int i, ierr;
13:
16: pcis->pure_neumann = matis->pure_neumann;
18: /*
19: Creating the local vector vec1_N, containing the inverse of the number
20: of subdomains to which each local node (either owned or ghost)
21: pertains. To accomplish that, we scatter local vectors of 1's to
22: a global vector (adding the values); scatter the result back to
23: local vectors and finally invert the result.
24: */
25: {
26: Vec counter;
27: Scalar one=1.0, zero=0.0;
28: VecDuplicate(matis->x,&pcis->vec1_N);
29: VecDuplicate(pc->vec,&counter); /* temporary auxiliar vector */
30: VecSet(&zero,counter);
31: VecSet(&one,pcis->vec1_N);
32: VecScatterBegin(pcis->vec1_N,counter,ADD_VALUES,SCATTER_REVERSE,matis->ctx);
33: VecScatterEnd (pcis->vec1_N,counter,ADD_VALUES,SCATTER_REVERSE,matis->ctx);
34: VecScatterBegin(counter,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD,matis->ctx);
35: VecScatterEnd (counter,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD,matis->ctx);
36: VecDestroy(counter);
37: }
38: /*
39: Creating local and global index sets for interior and
40: inteface nodes. Notice that interior nodes have D[i]==1.0.
41: */
42: {
43: int n_I;
44: int *idx_I_local,*idx_B_local,*idx_I_global,*idx_B_global;
45: Scalar *array;
46: /* Identifying interior and interface nodes, in local numbering */
47: VecGetSize(pcis->vec1_N,&pcis->n);
48: VecGetArray(pcis->vec1_N,&array);
49: PetscMalloc(pcis->n*sizeof(int),&idx_I_local);
50: PetscMalloc(pcis->n*sizeof(int),&idx_B_local);
51: for (i=0, pcis->n_B=0, n_I=0; i<pcis->n; i++) {
52: if (array[i] == 1.0) { idx_I_local[n_I] = i; n_I++; }
53: else { idx_B_local[pcis->n_B] = i; pcis->n_B++; }
54: }
55: /* Getting the global numbering */
56: idx_B_global = idx_I_local + n_I; /* Just avoiding allocating extra memory, since we have vacant space */
57: idx_I_global = idx_B_local + pcis->n_B;
58: ISLocalToGlobalMappingApply(matis->mapping,pcis->n_B,idx_B_local,idx_B_global);
59: ISLocalToGlobalMappingApply(matis->mapping,n_I, idx_I_local,idx_I_global);
60: /* Creating the index sets. */
61: ISCreateGeneral(MPI_COMM_SELF,pcis->n_B,idx_B_local, &pcis->is_B_local);
62: ISCreateGeneral(MPI_COMM_SELF,pcis->n_B,idx_B_global,&pcis->is_B_global);
63: ISCreateGeneral(MPI_COMM_SELF,n_I ,idx_I_local, &pcis->is_I_local);
64: ISCreateGeneral(MPI_COMM_SELF,n_I ,idx_I_global,&pcis->is_I_global);
65: /* Freeing memory and restoring arrays */
66: PetscFree(idx_B_local);
67: PetscFree(idx_I_local);
68: VecRestoreArray(pcis->vec1_N,&array);
69: }
71: /*
72: Extracting the blocks A_II, A_BI, A_IB and A_BB from A. If the numbering
73: is such that interior nodes come first than the interface ones, we have
75: [ | ]
76: [ A_II | A_IB ]
77: A = [ | ]
78: [-----------+------]
79: [ A_BI | A_BB ]
80: */
82: MatGetSubMatrix(matis->A,pcis->is_I_local,pcis->is_I_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_II);
83: MatGetSubMatrix(matis->A,pcis->is_I_local,pcis->is_B_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_IB);
84: MatGetSubMatrix(matis->A,pcis->is_B_local,pcis->is_I_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_BI);
85: MatGetSubMatrix(matis->A,pcis->is_B_local,pcis->is_B_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_BB);
87: /*
88: Creating work vectors and arrays
89: */
90: /* pcis->vec1_N has already been created */
91: VecDuplicate(pcis->vec1_N,&pcis->vec2_N);
92: VecCreateSeq(PETSC_COMM_SELF,pcis->n-pcis->n_B,&pcis->vec1_D);
93: VecDuplicate(pcis->vec1_D,&pcis->vec2_D);
94: VecDuplicate(pcis->vec1_D,&pcis->vec3_D);
95: VecCreateSeq(PETSC_COMM_SELF,pcis->n_B,&pcis->vec1_B);
96: VecDuplicate(pcis->vec1_B,&pcis->vec2_B);
97: VecDuplicate(pcis->vec1_B,&pcis->vec3_B);
98: {
99: Vec global;
100: PCGetVector(pc,&global);
101: VecDuplicate(global,&pcis->vec1_global);
102: }
103: PetscMalloc((pcis->n)*sizeof(Scalar),&pcis->work_N);
105: /* Creating the scatter contexts */
106: VecScatterCreate(pc->vec,pcis->is_I_global,pcis->vec1_D,(IS)0,&pcis->global_to_D);
107: VecScatterCreate(pcis->vec1_N,pcis->is_B_local,pcis->vec1_B,(IS)0,&pcis->N_to_B);
108: VecScatterCreate(pc->vec,pcis->is_B_global,pcis->vec1_B,(IS)0,&pcis->global_to_B);
110: /* Creating scaling "matrix" D, from information in vec1_N */
111: VecDuplicate(pcis->vec1_B,&pcis->D);
112: VecScatterBegin(pcis->vec1_N,pcis->D,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);
113: VecScatterEnd (pcis->vec1_N,pcis->D,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);
114: VecReciprocal(pcis->D);
116: /* See historical note 01, at the bottom of this file. */
118: /*
119: Creating the SLES contexts for the local Dirichlet and Neumann problems.
120: */
121: {
122: PC pc_ctx;
123: KSP ksp_ctx;
124: /* Dirichlet */
125: SLESCreate(PETSC_COMM_SELF,&pcis->sles_D);
126: SLESSetOperators(pcis->sles_D,pcis->A_II,pcis->A_II,SAME_PRECONDITIONER);
127: SLESSetOptionsPrefix(pcis->sles_D,"localD_");
128: SLESGetKSP(pcis->sles_D,&ksp_ctx);
129: SLESGetPC(pcis->sles_D,&pc_ctx);
130: PCSetType(pc_ctx,PCLU);
131: KSPSetType(ksp_ctx,KSPPREONLY);
132: SLESSetFromOptions(pcis->sles_D);
133: /* the vectors in the following line are dummy arguments, just telling the SLES the vector size. Values are not used */
134: SLESSetUp(pcis->sles_D,pcis->vec1_D,pcis->vec2_D);
135: /* Neumann */
136: SLESCreate(PETSC_COMM_SELF,&pcis->sles_N);
137: SLESSetOperators(pcis->sles_N,matis->A,matis->A,SAME_PRECONDITIONER);
138: SLESSetOptionsPrefix(pcis->sles_N,"localN_");
139: SLESGetKSP(pcis->sles_N,&ksp_ctx);
140: SLESGetPC(pcis->sles_N,&pc_ctx);
141: PCSetType(pc_ctx,PCLU);
142: KSPSetType(ksp_ctx,KSPPREONLY);
143: SLESSetFromOptions(pcis->sles_N);
144: {
145: PetscTruth damp_fixed,
146: remove_nullspace_fixed,
147: set_damping_factor_floating,
148: not_damp_floating,
149: not_remove_nullspace_floating;
150: double fixed_factor,
151: floating_factor;
153: PetscOptionsGetDouble(pc_ctx->prefix,"-pc_is_damp_fixed",&fixed_factor,&damp_fixed);
154: if (!damp_fixed) { fixed_factor = 0.0; }
155: PetscOptionsHasName(pc_ctx->prefix,"-pc_is_damp_fixed",&damp_fixed);
157: PetscOptionsHasName(pc_ctx->prefix,"-pc_is_remove_nullspace_fixed",&remove_nullspace_fixed);
159: PetscOptionsGetDouble(pc_ctx->prefix,"-pc_is_set_damping_factor_floating",
160: &floating_factor,&set_damping_factor_floating);
161: if (!set_damping_factor_floating) { floating_factor = 0.0; }
162: PetscOptionsHasName(pc_ctx->prefix,"-pc_is_set_damping_factor_floating",&set_damping_factor_floating);
163: if (!set_damping_factor_floating) { floating_factor = 1.e-12; }
165: PetscOptionsHasName(pc_ctx->prefix,"-pc_is_not_damp_floating",¬_damp_floating);
167: PetscOptionsHasName(pc_ctx->prefix,"-pc_is_not_remove_nullspace_floating",¬_remove_nullspace_floating);
169: if (pcis->pure_neumann) { /* floating subdomain */
170: if (!(not_damp_floating)) {
171: PCLUSetDamping (pc_ctx,floating_factor);
172: PCILUSetDamping(pc_ctx,floating_factor);
173: }
174: if (!(not_remove_nullspace_floating)){
175: MatNullSpace nullsp;
176: MatNullSpaceCreate(PETSC_COMM_SELF,1,0,PETSC_NULL,&nullsp);
177: PCNullSpaceAttach(pc_ctx,nullsp);
178: MatNullSpaceDestroy(nullsp);
179: }
180: } else { /* fixed subdomain */
181: if (damp_fixed) {
182: PCLUSetDamping (pc_ctx,fixed_factor);
183: PCILUSetDamping(pc_ctx,fixed_factor);
184: }
185: if (remove_nullspace_fixed) {
186: MatNullSpace nullsp;
187: MatNullSpaceCreate(PETSC_COMM_SELF,1,0,PETSC_NULL,&nullsp);
188: PCNullSpaceAttach(pc_ctx,nullsp);
189: MatNullSpaceDestroy(nullsp);
190: }
191: }
192: }
193: /* the vectors in the following line are dummy arguments, just telling the SLES the vector size. Values are not used */
194: SLESSetUp(pcis->sles_N,pcis->vec1_N,pcis->vec2_N);
195: }
197: ISLocalToGlobalMappingGetInfo(((Mat_IS*)(pc->mat->data))->mapping,&(pcis->n_neigh),&(pcis->neigh),
198: &(pcis->n_shared),&(pcis->shared));
199: pcis->ISLocalToGlobalMappingGetInfoWasCalled = PETSC_TRUE;
201: return(0);
202: }
204: /* -------------------------------------------------------------------------- */
205: /*
206: PCISDestroy -
207: */
208: int PCISDestroy(PC pc)
209: {
210: PC_IS *pcis = (PC_IS*)(pc->data);
211: int ierr;
215: if (pcis->is_B_local) {ISDestroy(pcis->is_B_local);}
216: if (pcis->is_I_local) {ISDestroy(pcis->is_I_local);}
217: if (pcis->is_B_global) {ISDestroy(pcis->is_B_global);}
218: if (pcis->is_I_global) {ISDestroy(pcis->is_I_global);}
219: if (pcis->A_II) {MatDestroy(pcis->A_II);}
220: if (pcis->A_IB) {MatDestroy(pcis->A_IB);}
221: if (pcis->A_BI) {MatDestroy(pcis->A_BI);}
222: if (pcis->A_BB) {MatDestroy(pcis->A_BB);}
223: if (pcis->D) {VecDestroy(pcis->D);}
224: if (pcis->sles_N) {SLESDestroy(pcis->sles_N);}
225: if (pcis->sles_D) {SLESDestroy(pcis->sles_D);}
226: if (pcis->vec1_N) {VecDestroy(pcis->vec1_N);}
227: if (pcis->vec2_N) {VecDestroy(pcis->vec2_N);}
228: if (pcis->vec1_D) {VecDestroy(pcis->vec1_D);}
229: if (pcis->vec2_D) {VecDestroy(pcis->vec2_D);}
230: if (pcis->vec3_D) {VecDestroy(pcis->vec3_D);}
231: if (pcis->vec1_B) {VecDestroy(pcis->vec1_B);}
232: if (pcis->vec2_B) {VecDestroy(pcis->vec2_B);}
233: if (pcis->vec3_B) {VecDestroy(pcis->vec3_B);}
234: if (pcis->vec1_global) {VecDestroy(pcis->vec1_global);}
235: if (pcis->work_N) {PetscFree(pcis->work_N);}
236: if (pcis->global_to_D) {VecScatterDestroy(pcis->global_to_D);}
237: if (pcis->N_to_B) {VecScatterDestroy(pcis->N_to_B);}
238: if (pcis->global_to_B) {VecScatterDestroy(pcis->global_to_B);}
239: if (pcis->ISLocalToGlobalMappingGetInfoWasCalled) {
240: ISLocalToGlobalMappingRestoreInfo((ISLocalToGlobalMapping)0,&(pcis->n_neigh),&(pcis->neigh),&(pcis->n_shared),&(pcis->shared));
241: }
243: return(0);
244: }
246: /* -------------------------------------------------------------------------- */
247: /*
248: PCISCreate -
249: */
250: int PCISCreate(PC pc)
251: {
252: PC_IS *pcis = (PC_IS*)(pc->data);
256: pcis->is_B_local = 0;
257: pcis->is_I_local = 0;
258: pcis->is_B_global = 0;
259: pcis->is_I_global = 0;
260: pcis->A_II = 0;
261: pcis->A_IB = 0;
262: pcis->A_BI = 0;
263: pcis->A_BB = 0;
264: pcis->D = 0;
265: pcis->sles_N = 0;
266: pcis->sles_D = 0;
267: pcis->vec1_N = 0;
268: pcis->vec2_N = 0;
269: pcis->vec1_D = 0;
270: pcis->vec2_D = 0;
271: pcis->vec3_D = 0;
272: pcis->vec1_B = 0;
273: pcis->vec2_B = 0;
274: pcis->vec3_B = 0;
275: pcis->vec1_global = 0;
276: pcis->work_N = 0;
277: pcis->global_to_D = 0;
278: pcis->N_to_B = 0;
279: pcis->global_to_B = 0;
280: pcis->ISLocalToGlobalMappingGetInfoWasCalled = PETSC_FALSE;
282: return(0);
283: }
285: /* -------------------------------------------------------------------------- */
286: /*
287: PCISApplySchur -
289: Input parameters:
290: . pc - preconditioner context
291: . v - vector to which the Schur complement is to be applied (it is NOT modified inside this function, UNLESS vec2_B is null)
293: Output parameters:
294: . vec1_B - result of Schur complement applied to chunk
295: . vec2_B - garbage (used as work space), or null (and v is used as workspace)
296: . vec1_D - garbage (used as work space)
297: . vec2_D - garbage (used as work space)
299: */
300: int PCISApplySchur(PC pc, Vec v, Vec vec1_B, Vec vec2_B, Vec vec1_D, Vec vec2_D)
301: {
302: int ierr, its;
303: Scalar m_one = -1.0;
304: PC_IS *pcis = (PC_IS*)(pc->data);
308: if (vec2_B == (Vec)0) { vec2_B = v; }
310: MatMult(pcis->A_BB,v,vec1_B);
311: MatMult(pcis->A_IB,v,vec1_D);
312: SLESSolve(pcis->sles_D,vec1_D,vec2_D,&its);
313: MatMult(pcis->A_BI,vec2_D,vec2_B);
314: VecAXPY(&m_one,vec2_B,vec1_B);
316: return(0);
317: }
319: /* -------------------------------------------------------------------------- */
320: /*
321: PCISScatterArrayNToVecB - Scatters interface node values from a big array (of all local nodes, interior or interface,
322: including ghosts) into an interface vector, when in SCATTER_FORWARD mode, or vice-versa, when in SCATTER_REVERSE
323: mode.
325: Input parameters:
326: . pc - preconditioner context
327: . array_N - [when in SCATTER_FORWARD mode] Array to be scattered into the vector
328: . v_B - [when in SCATTER_REVERSE mode] Vector to be scattered into the array
330: Output parameter:
331: . array_N - [when in SCATTER_REVERSE mode] Array to receive the scattered vector
332: . v_B - [when in SCATTER_FORWARD mode] Vector to receive the scattered array
334: Notes:
335: The entries in the array that do not correspond to interface nodes remain unaltered.
336: */
337: int PCISScatterArrayNToVecB (Scalar *array_N, Vec v_B, InsertMode imode, ScatterMode smode, PC pc)
338: {
339: int i, ierr, *index;
340: Scalar *array_B;
341: PC_IS *pcis = (PC_IS*)(pc->data);
345: VecGetArray(v_B,&array_B);
346: ISGetIndices(pcis->is_B_local,&index);
348: if (smode == SCATTER_FORWARD) {
349: if (imode == INSERT_VALUES) {
350: for (i=0; i<pcis->n_B; i++) { array_B[i] = array_N[index[i]]; }
351: } else { /* ADD_VALUES */
352: for (i=0; i<pcis->n_B; i++) { array_B[i] += array_N[index[i]]; }
353: }
354: } else { /* SCATTER_REVERSE */
355: if (imode == INSERT_VALUES) {
356: for (i=0; i<pcis->n_B; i++) { array_N[index[i]] = array_B[i]; }
357: } else { /* ADD_VALUES */
358: for (i=0; i<pcis->n_B; i++) { array_N[index[i]] += array_B[i]; }
359: }
360: }
362: ISRestoreIndices(pcis->is_B_local,&index);
363: VecRestoreArray(v_B,&array_B);
365: return(0);
366: }
368: /* -------------------------------------------------------------------------- */
369: /*
370: PCISApplyInvSchur - Solves the Neumann problem related to applying the inverse of the Schur complement.
371: More precisely, solves the problem:
372: [ A_II A_IB ] [ . ] [ 0 ]
373: [ ] [ ] = [ ]
374: [ A_BI A_BB ] [ x ] [ b ]
376: Input parameters:
377: . pc - preconditioner context
378: . b - vector of local interface nodes (including ghosts)
380: Output parameters:
381: . x - vector of local interface nodes (including ghosts); returns the application of the inverse of the Schur
382: complement to b
383: . vec1_N - vector of local nodes (interior and interface, including ghosts); returns garbage (used as work space)
384: . vec2_N - vector of local nodes (interior and interface, including ghosts); returns garbage (used as work space)
386: */
387: int PCISApplyInvSchur (PC pc, Vec b, Vec x, Vec vec1_N, Vec vec2_N)
388: {
389: int ierr, its;
390: PC_IS *pcis = (PC_IS*)(pc->data);
391: Scalar zero = 0.0;
395: /*
396: Neumann solvers.
397: Applying the inverse of the local Schur complement, i.e, solving a Neumann
398: Problem with zero at the interior nodes of the RHS and extracting the interface
399: part of the solution. inverse Schur complement is applied to b and the result
400: is stored in x.
401: */
402: /* Setting the RHS vec1_N */
403: VecSet(&zero,vec1_N);
404: VecScatterBegin(b,vec1_N,INSERT_VALUES,SCATTER_REVERSE,pcis->N_to_B);
405: VecScatterEnd (b,vec1_N,INSERT_VALUES,SCATTER_REVERSE,pcis->N_to_B);
406: /* Checking for consistency of the RHS */
407: {
408: PetscTruth flg;
409: PetscOptionsHasName(PETSC_NULL,"-check_consistency",&flg);
410: if (flg) {
411: Scalar average;
412: VecSum(vec1_N,&average);
413: average = average / ((PetscReal)pcis->n);
414: if (pcis->pure_neumann) {
415: PetscViewerASCIISynchronizedPrintf(PETSC_VIEWER_STDOUT_(pc->comm),"Subdomain %04d is floating. Average = % 1.14en",
416: PetscGlobalRank,PetscAbsScalar(average));
417: } else {
418: PetscViewerASCIISynchronizedPrintf(PETSC_VIEWER_STDOUT_(pc->comm),"Subdomain %04d is fixed. Average = % 1.14en",
419: PetscGlobalRank,PetscAbsScalar(average));
420: }
421: PetscViewerFlush(PETSC_VIEWER_STDOUT_(pc->comm));
422: }
423: }
424: /* Solving the system for vec2_N */
425: SLESSolve(pcis->sles_N,vec1_N,vec2_N,&its);
426: /* Extracting the local interface vector out of the solution */
427: VecScatterBegin(vec2_N,x,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);
428: VecScatterEnd (vec2_N,x,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);
430: return(0);
431: }