1 #define PETSCKSP_DLL 2 3 #include "../src/ksp/pc/impls/is/pcis.h" 4 5 /* -------------------------------------------------------------------------- */ 6 /* 7 PCISSetUp - 8 */ 9 #undef __FUNCT__ 10 #define __FUNCT__ "PCISSetUp" 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 19 PetscFunctionBegin; 20 ierr = PetscTypeCompare((PetscObject)pc->mat,MATIS,&flg);CHKERRQ(ierr); 21 if (!flg){ 22 SETERRQ(PETSC_ERR_ARG_WRONG,"Preconditioner type of Neumann Neumman requires matrix of type MATIS"); 23 } 24 25 pcis->pure_neumann = matis->pure_neumann; 26 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 ierr = VecDuplicate(matis->x,&pcis->vec1_N);CHKERRQ(ierr); 37 ierr = MatGetVecs(pc->pmat,&counter,0);CHKERRQ(ierr); /* temporary auxiliar vector */ 38 ierr = VecSet(counter,0.0);CHKERRQ(ierr); 39 ierr = VecSet(pcis->vec1_N,1.0);CHKERRQ(ierr); 40 ierr = VecScatterBegin(matis->ctx,pcis->vec1_N,counter,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 41 ierr = VecScatterEnd (matis->ctx,pcis->vec1_N,counter,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 42 ierr = VecScatterBegin(matis->ctx,counter,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 43 ierr = VecScatterEnd (matis->ctx,counter,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 44 ierr = VecDestroy(counter);CHKERRQ(ierr); 45 } 46 /* 47 Creating local and global index sets for interior and 48 inteface nodes. Notice that interior nodes have D[i]==1.0. 49 */ 50 { 51 PetscInt n_I; 52 PetscInt *idx_I_local,*idx_B_local,*idx_I_global,*idx_B_global; 53 PetscScalar *array; 54 /* Identifying interior and interface nodes, in local numbering */ 55 ierr = VecGetSize(pcis->vec1_N,&pcis->n);CHKERRQ(ierr); 56 ierr = VecGetArray(pcis->vec1_N,&array);CHKERRQ(ierr); 57 ierr = PetscMalloc(pcis->n*sizeof(PetscInt),&idx_I_local);CHKERRQ(ierr); 58 ierr = PetscMalloc(pcis->n*sizeof(PetscInt),&idx_B_local);CHKERRQ(ierr); 59 for (i=0, pcis->n_B=0, n_I=0; i<pcis->n; i++) { 60 if (array[i] == 1.0) { idx_I_local[n_I] = i; n_I++; } 61 else { idx_B_local[pcis->n_B] = i; pcis->n_B++; } 62 } 63 /* Getting the global numbering */ 64 idx_B_global = idx_I_local + n_I; /* Just avoiding allocating extra memory, since we have vacant space */ 65 idx_I_global = idx_B_local + pcis->n_B; 66 ierr = ISLocalToGlobalMappingApply(matis->mapping,pcis->n_B,idx_B_local,idx_B_global);CHKERRQ(ierr); 67 ierr = ISLocalToGlobalMappingApply(matis->mapping,n_I, idx_I_local,idx_I_global);CHKERRQ(ierr); 68 /* Creating the index sets. */ 69 ierr = ISCreateGeneral(MPI_COMM_SELF,pcis->n_B,idx_B_local, &pcis->is_B_local);CHKERRQ(ierr); 70 ierr = ISCreateGeneral(MPI_COMM_SELF,pcis->n_B,idx_B_global,&pcis->is_B_global);CHKERRQ(ierr); 71 ierr = ISCreateGeneral(MPI_COMM_SELF,n_I ,idx_I_local, &pcis->is_I_local);CHKERRQ(ierr); 72 ierr = ISCreateGeneral(MPI_COMM_SELF,n_I ,idx_I_global,&pcis->is_I_global);CHKERRQ(ierr); 73 /* Freeing memory and restoring arrays */ 74 ierr = PetscFree(idx_B_local);CHKERRQ(ierr); 75 ierr = PetscFree(idx_I_local);CHKERRQ(ierr); 76 ierr = VecRestoreArray(pcis->vec1_N,&array);CHKERRQ(ierr); 77 } 78 79 /* 80 Extracting the blocks A_II, A_BI, A_IB and A_BB from A. If the numbering 81 is such that interior nodes come first than the interface ones, we have 82 83 [ | ] 84 [ A_II | A_IB ] 85 A = [ | ] 86 [-----------+------] 87 [ A_BI | A_BB ] 88 */ 89 90 ierr = MatGetSubMatrix(matis->A,pcis->is_I_local,pcis->is_I_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_II);CHKERRQ(ierr); 91 ierr = MatGetSubMatrix(matis->A,pcis->is_I_local,pcis->is_B_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_IB);CHKERRQ(ierr); 92 ierr = MatGetSubMatrix(matis->A,pcis->is_B_local,pcis->is_I_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_BI);CHKERRQ(ierr); 93 ierr = MatGetSubMatrix(matis->A,pcis->is_B_local,pcis->is_B_local,PETSC_DECIDE,MAT_INITIAL_MATRIX,&pcis->A_BB);CHKERRQ(ierr); 94 95 /* 96 Creating work vectors and arrays 97 */ 98 /* pcis->vec1_N has already been created */ 99 ierr = VecDuplicate(pcis->vec1_N,&pcis->vec2_N);CHKERRQ(ierr); 100 ierr = VecCreateSeq(PETSC_COMM_SELF,pcis->n-pcis->n_B,&pcis->vec1_D);CHKERRQ(ierr); 101 ierr = VecDuplicate(pcis->vec1_D,&pcis->vec2_D);CHKERRQ(ierr); 102 ierr = VecDuplicate(pcis->vec1_D,&pcis->vec3_D);CHKERRQ(ierr); 103 ierr = VecCreateSeq(PETSC_COMM_SELF,pcis->n_B,&pcis->vec1_B);CHKERRQ(ierr); 104 ierr = VecDuplicate(pcis->vec1_B,&pcis->vec2_B);CHKERRQ(ierr); 105 ierr = VecDuplicate(pcis->vec1_B,&pcis->vec3_B);CHKERRQ(ierr); 106 ierr = MatGetVecs(pc->pmat,&pcis->vec1_global,0);CHKERRQ(ierr); 107 ierr = PetscMalloc((pcis->n)*sizeof(PetscScalar),&pcis->work_N);CHKERRQ(ierr); 108 109 /* Creating the scatter contexts */ 110 ierr = VecScatterCreate(pcis->vec1_global,pcis->is_I_global,pcis->vec1_D,(IS)0,&pcis->global_to_D);CHKERRQ(ierr); 111 ierr = VecScatterCreate(pcis->vec1_N,pcis->is_B_local,pcis->vec1_B,(IS)0,&pcis->N_to_B);CHKERRQ(ierr); 112 ierr = VecScatterCreate(pcis->vec1_global,pcis->is_B_global,pcis->vec1_B,(IS)0,&pcis->global_to_B);CHKERRQ(ierr); 113 114 /* Creating scaling "matrix" D, from information in vec1_N */ 115 ierr = VecDuplicate(pcis->vec1_B,&pcis->D);CHKERRQ(ierr); 116 ierr = VecScatterBegin(pcis->N_to_B,pcis->vec1_N,pcis->D,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 117 ierr = VecScatterEnd (pcis->N_to_B,pcis->vec1_N,pcis->D,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 118 ierr = VecReciprocal(pcis->D);CHKERRQ(ierr); 119 120 /* See historical note 01, at the bottom of this file. */ 121 122 /* 123 Creating the KSP contexts for the local Dirichlet and Neumann problems. 124 */ 125 { 126 PC pc_ctx; 127 /* Dirichlet */ 128 ierr = KSPCreate(PETSC_COMM_SELF,&pcis->ksp_D);CHKERRQ(ierr); 129 ierr = PetscObjectIncrementTabLevel((PetscObject)pcis->ksp_D,(PetscObject)pc,1);CHKERRQ(ierr); 130 ierr = KSPSetOperators(pcis->ksp_D,pcis->A_II,pcis->A_II,SAME_PRECONDITIONER);CHKERRQ(ierr); 131 ierr = KSPSetOptionsPrefix(pcis->ksp_D,"is_localD_");CHKERRQ(ierr); 132 ierr = KSPGetPC(pcis->ksp_D,&pc_ctx);CHKERRQ(ierr); 133 ierr = PCSetType(pc_ctx,PCLU);CHKERRQ(ierr); 134 ierr = KSPSetType(pcis->ksp_D,KSPPREONLY);CHKERRQ(ierr); 135 ierr = KSPSetFromOptions(pcis->ksp_D);CHKERRQ(ierr); 136 /* the vectors in the following line are dummy arguments, just telling the KSP the vector size. Values are not used */ 137 ierr = KSPSetUp(pcis->ksp_D);CHKERRQ(ierr); 138 /* Neumann */ 139 ierr = KSPCreate(PETSC_COMM_SELF,&pcis->ksp_N);CHKERRQ(ierr); 140 ierr = PetscObjectIncrementTabLevel((PetscObject)pcis->ksp_N,(PetscObject)pc,1);CHKERRQ(ierr); 141 ierr = KSPSetOperators(pcis->ksp_N,matis->A,matis->A,SAME_PRECONDITIONER);CHKERRQ(ierr); 142 ierr = KSPSetOptionsPrefix(pcis->ksp_N,"is_localN_");CHKERRQ(ierr); 143 ierr = KSPGetPC(pcis->ksp_N,&pc_ctx);CHKERRQ(ierr); 144 ierr = PCSetType(pc_ctx,PCLU);CHKERRQ(ierr); 145 ierr = KSPSetType(pcis->ksp_N,KSPPREONLY);CHKERRQ(ierr); 146 ierr = KSPSetFromOptions(pcis->ksp_N);CHKERRQ(ierr); 147 { 148 PetscTruth damp_fixed, 149 remove_nullspace_fixed, 150 set_damping_factor_floating, 151 not_damp_floating, 152 not_remove_nullspace_floating; 153 PetscReal fixed_factor, 154 floating_factor; 155 156 ierr = PetscOptionsGetReal(((PetscObject)pc_ctx)->prefix,"-pc_is_damp_fixed",&fixed_factor,&damp_fixed);CHKERRQ(ierr); 157 if (!damp_fixed) { fixed_factor = 0.0; } 158 ierr = PetscOptionsHasName(((PetscObject)pc_ctx)->prefix,"-pc_is_damp_fixed",&damp_fixed);CHKERRQ(ierr); 159 160 ierr = PetscOptionsHasName(((PetscObject)pc_ctx)->prefix,"-pc_is_remove_nullspace_fixed",&remove_nullspace_fixed);CHKERRQ(ierr); 161 162 ierr = PetscOptionsGetReal(((PetscObject)pc_ctx)->prefix,"-pc_is_set_damping_factor_floating", 163 &floating_factor,&set_damping_factor_floating);CHKERRQ(ierr); 164 if (!set_damping_factor_floating) { floating_factor = 0.0; } 165 ierr = PetscOptionsHasName(((PetscObject)pc_ctx)->prefix,"-pc_is_set_damping_factor_floating",&set_damping_factor_floating);CHKERRQ(ierr); 166 if (!set_damping_factor_floating) { floating_factor = 1.e-12; } 167 168 ierr = PetscOptionsHasName(((PetscObject)pc_ctx)->prefix,"-pc_is_not_damp_floating",¬_damp_floating);CHKERRQ(ierr); 169 170 ierr = PetscOptionsHasName(((PetscObject)pc_ctx)->prefix,"-pc_is_not_remove_nullspace_floating",¬_remove_nullspace_floating);CHKERRQ(ierr); 171 172 if (pcis->pure_neumann) { /* floating subdomain */ 173 if (!(not_damp_floating)) { 174 ierr = PCFactorSetShiftNonzero(pc_ctx,floating_factor);CHKERRQ(ierr); 175 } 176 if (!(not_remove_nullspace_floating)){ 177 MatNullSpace nullsp; 178 ierr = MatNullSpaceCreate(PETSC_COMM_SELF,PETSC_TRUE,0,PETSC_NULL,&nullsp);CHKERRQ(ierr); 179 ierr = KSPSetNullSpace(pcis->ksp_N,nullsp);CHKERRQ(ierr); 180 ierr = MatNullSpaceDestroy(nullsp);CHKERRQ(ierr); 181 } 182 } else { /* fixed subdomain */ 183 if (damp_fixed) { 184 ierr = PCFactorSetShiftNonzero(pc_ctx,fixed_factor);CHKERRQ(ierr); 185 } 186 if (remove_nullspace_fixed) { 187 MatNullSpace nullsp; 188 ierr = MatNullSpaceCreate(PETSC_COMM_SELF,PETSC_TRUE,0,PETSC_NULL,&nullsp);CHKERRQ(ierr); 189 ierr = KSPSetNullSpace(pcis->ksp_N,nullsp);CHKERRQ(ierr); 190 ierr = MatNullSpaceDestroy(nullsp);CHKERRQ(ierr); 191 } 192 } 193 } 194 /* the vectors in the following line are dummy arguments, just telling the KSP the vector size. Values are not used */ 195 ierr = KSPSetUp(pcis->ksp_N);CHKERRQ(ierr); 196 } 197 198 ierr = ISLocalToGlobalMappingGetInfo(((Mat_IS*)(pc->mat->data))->mapping,&(pcis->n_neigh),&(pcis->neigh),&(pcis->n_shared),&(pcis->shared));CHKERRQ(ierr); 199 pcis->ISLocalToGlobalMappingGetInfoWasCalled = PETSC_TRUE; 200 PetscFunctionReturn(0); 201 } 202 203 /* -------------------------------------------------------------------------- */ 204 /* 205 PCISDestroy - 206 */ 207 #undef __FUNCT__ 208 #define __FUNCT__ "PCISDestroy" 209 PetscErrorCode PETSCKSP_DLLEXPORT PCISDestroy(PC pc) 210 { 211 PC_IS *pcis = (PC_IS*)(pc->data); 212 PetscErrorCode ierr; 213 214 PetscFunctionBegin; 215 if (pcis->is_B_local) {ierr = ISDestroy(pcis->is_B_local);CHKERRQ(ierr);} 216 if (pcis->is_I_local) {ierr = ISDestroy(pcis->is_I_local);CHKERRQ(ierr);} 217 if (pcis->is_B_global) {ierr = ISDestroy(pcis->is_B_global);CHKERRQ(ierr);} 218 if (pcis->is_I_global) {ierr = ISDestroy(pcis->is_I_global);CHKERRQ(ierr);} 219 if (pcis->A_II) {ierr = MatDestroy(pcis->A_II);CHKERRQ(ierr);} 220 if (pcis->A_IB) {ierr = MatDestroy(pcis->A_IB);CHKERRQ(ierr);} 221 if (pcis->A_BI) {ierr = MatDestroy(pcis->A_BI);CHKERRQ(ierr);} 222 if (pcis->A_BB) {ierr = MatDestroy(pcis->A_BB);CHKERRQ(ierr);} 223 if (pcis->D) {ierr = VecDestroy(pcis->D);CHKERRQ(ierr);} 224 if (pcis->ksp_N) {ierr = KSPDestroy(pcis->ksp_N);CHKERRQ(ierr);} 225 if (pcis->ksp_D) {ierr = KSPDestroy(pcis->ksp_D);CHKERRQ(ierr);} 226 if (pcis->vec1_N) {ierr = VecDestroy(pcis->vec1_N);CHKERRQ(ierr);} 227 if (pcis->vec2_N) {ierr = VecDestroy(pcis->vec2_N);CHKERRQ(ierr);} 228 if (pcis->vec1_D) {ierr = VecDestroy(pcis->vec1_D);CHKERRQ(ierr);} 229 if (pcis->vec2_D) {ierr = VecDestroy(pcis->vec2_D);CHKERRQ(ierr);} 230 if (pcis->vec3_D) {ierr = VecDestroy(pcis->vec3_D);CHKERRQ(ierr);} 231 if (pcis->vec1_B) {ierr = VecDestroy(pcis->vec1_B);CHKERRQ(ierr);} 232 if (pcis->vec2_B) {ierr = VecDestroy(pcis->vec2_B);CHKERRQ(ierr);} 233 if (pcis->vec3_B) {ierr = VecDestroy(pcis->vec3_B);CHKERRQ(ierr);} 234 if (pcis->vec1_global) {ierr = VecDestroy(pcis->vec1_global);CHKERRQ(ierr);} 235 if (pcis->global_to_D) {ierr = VecScatterDestroy(pcis->global_to_D);CHKERRQ(ierr);} 236 if (pcis->N_to_B) {ierr = VecScatterDestroy(pcis->N_to_B);CHKERRQ(ierr);} 237 if (pcis->global_to_B) {ierr = VecScatterDestroy(pcis->global_to_B);CHKERRQ(ierr);} 238 ierr = PetscFree(pcis->work_N);CHKERRQ(ierr); 239 if (pcis->ISLocalToGlobalMappingGetInfoWasCalled) { 240 ierr = ISLocalToGlobalMappingRestoreInfo((ISLocalToGlobalMapping)0,&(pcis->n_neigh),&(pcis->neigh),&(pcis->n_shared),&(pcis->shared));CHKERRQ(ierr); 241 } 242 PetscFunctionReturn(0); 243 } 244 245 /* -------------------------------------------------------------------------- */ 246 /* 247 PCISCreate - 248 */ 249 #undef __FUNCT__ 250 #define __FUNCT__ "PCISCreate" 251 PetscErrorCode PETSCKSP_DLLEXPORT PCISCreate(PC pc) 252 { 253 PC_IS *pcis = (PC_IS*)(pc->data); 254 255 PetscFunctionBegin; 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->ksp_N = 0; 266 pcis->ksp_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; 281 PetscFunctionReturn(0); 282 } 283 284 /* -------------------------------------------------------------------------- */ 285 /* 286 PCISApplySchur - 287 288 Input parameters: 289 . pc - preconditioner context 290 . v - vector to which the Schur complement is to be applied (it is NOT modified inside this function, UNLESS vec2_B is null) 291 292 Output parameters: 293 . vec1_B - result of Schur complement applied to chunk 294 . vec2_B - garbage (used as work space), or null (and v is used as workspace) 295 . vec1_D - garbage (used as work space) 296 . vec2_D - garbage (used as work space) 297 298 */ 299 #undef __FUNCT__ 300 #define __FUNCT__ "PCIterSuApplySchur" 301 PetscErrorCode PETSCKSP_DLLEXPORT PCISApplySchur(PC pc, Vec v, Vec vec1_B, Vec vec2_B, Vec vec1_D, Vec vec2_D) 302 { 303 PetscErrorCode ierr; 304 PC_IS *pcis = (PC_IS*)(pc->data); 305 306 PetscFunctionBegin; 307 if (!vec2_B) { vec2_B = v; } 308 309 ierr = MatMult(pcis->A_BB,v,vec1_B);CHKERRQ(ierr); 310 ierr = MatMult(pcis->A_IB,v,vec1_D);CHKERRQ(ierr); 311 ierr = KSPSolve(pcis->ksp_D,vec1_D,vec2_D);CHKERRQ(ierr); 312 ierr = MatMult(pcis->A_BI,vec2_D,vec2_B);CHKERRQ(ierr); 313 ierr = VecAXPY(vec1_B,-1.0,vec2_B);CHKERRQ(ierr); 314 PetscFunctionReturn(0); 315 } 316 317 /* -------------------------------------------------------------------------- */ 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. 322 323 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 327 328 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 331 332 Notes: 333 The entries in the array that do not correspond to interface nodes remain unaltered. 334 */ 335 #undef __FUNCT__ 336 #define __FUNCT__ "PCISScatterArrayNToVecB" 337 PetscErrorCode PETSCKSP_DLLEXPORT PCISScatterArrayNToVecB (PetscScalar *array_N, Vec v_B, InsertMode imode, ScatterMode smode, PC pc) 338 { 339 PetscInt i; 340 const PetscInt *idex; 341 PetscErrorCode ierr; 342 PetscScalar *array_B; 343 PC_IS *pcis = (PC_IS*)(pc->data); 344 345 PetscFunctionBegin; 346 ierr = VecGetArray(v_B,&array_B);CHKERRQ(ierr); 347 ierr = ISGetIndices(pcis->is_B_local,&idex);CHKERRQ(ierr); 348 349 if (smode == SCATTER_FORWARD) { 350 if (imode == INSERT_VALUES) { 351 for (i=0; i<pcis->n_B; i++) { array_B[i] = array_N[idex[i]]; } 352 } else { /* ADD_VALUES */ 353 for (i=0; i<pcis->n_B; i++) { array_B[i] += array_N[idex[i]]; } 354 } 355 } else { /* SCATTER_REVERSE */ 356 if (imode == INSERT_VALUES) { 357 for (i=0; i<pcis->n_B; i++) { array_N[idex[i]] = array_B[i]; } 358 } else { /* ADD_VALUES */ 359 for (i=0; i<pcis->n_B; i++) { array_N[idex[i]] += array_B[i]; } 360 } 361 } 362 ierr = ISRestoreIndices(pcis->is_B_local,&idex);CHKERRQ(ierr); 363 ierr = VecRestoreArray(v_B,&array_B);CHKERRQ(ierr); 364 PetscFunctionReturn(0); 365 } 366 367 /* -------------------------------------------------------------------------- */ 368 /* 369 PCISApplyInvSchur - Solves the Neumann problem related to applying the inverse of the Schur complement. 370 More precisely, solves the problem: 371 [ A_II A_IB ] [ . ] [ 0 ] 372 [ ] [ ] = [ ] 373 [ A_BI A_BB ] [ x ] [ b ] 374 375 Input parameters: 376 . pc - preconditioner context 377 . b - vector of local interface nodes (including ghosts) 378 379 Output parameters: 380 . x - vector of local interface nodes (including ghosts); returns the application of the inverse of the Schur 381 complement to b 382 . vec1_N - vector of local nodes (interior and interface, including ghosts); returns garbage (used as work space) 383 . vec2_N - vector of local nodes (interior and interface, including ghosts); returns garbage (used as work space) 384 385 */ 386 #undef __FUNCT__ 387 #define __FUNCT__ "PCISApplyInvSchur" 388 PetscErrorCode PETSCKSP_DLLEXPORT PCISApplyInvSchur (PC pc, Vec b, Vec x, Vec vec1_N, Vec vec2_N) 389 { 390 PetscErrorCode ierr; 391 PC_IS *pcis = (PC_IS*)(pc->data); 392 393 PetscFunctionBegin; 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 ierr = VecSet(vec1_N,0.0);CHKERRQ(ierr); 403 ierr = VecScatterBegin(pcis->N_to_B,b,vec1_N,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 404 ierr = VecScatterEnd (pcis->N_to_B,b,vec1_N,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 405 /* Checking for consistency of the RHS */ 406 { 407 PetscTruth flg; 408 ierr = PetscOptionsHasName(PETSC_NULL,"-pc_is_check_consistency",&flg);CHKERRQ(ierr); 409 if (flg) { 410 PetscScalar average; 411 PetscViewer viewer; 412 ierr = PetscViewerASCIIGetStdout(((PetscObject)pc)->comm,&viewer);CHKERRQ(ierr); 413 414 ierr = VecSum(vec1_N,&average);CHKERRQ(ierr); 415 average = average / ((PetscReal)pcis->n); 416 if (pcis->pure_neumann) { 417 418 ierr = PetscViewerASCIISynchronizedPrintf(viewer,"Subdomain %04d is floating. Average = % 1.14e\n", 419 PetscGlobalRank,PetscAbsScalar(average));CHKERRQ(ierr); 420 } else { 421 ierr = PetscViewerASCIISynchronizedPrintf(viewer,"Subdomain %04d is fixed. Average = % 1.14e\n", 422 PetscGlobalRank,PetscAbsScalar(average));CHKERRQ(ierr); 423 } 424 ierr = PetscViewerFlush(viewer);CHKERRQ(ierr); 425 } 426 } 427 /* Solving the system for vec2_N */ 428 ierr = KSPSolve(pcis->ksp_N,vec1_N,vec2_N);CHKERRQ(ierr); 429 /* Extracting the local interface vector out of the solution */ 430 ierr = VecScatterBegin(pcis->N_to_B,vec2_N,x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 431 ierr = VecScatterEnd (pcis->N_to_B,vec2_N,x,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 432 PetscFunctionReturn(0); 433 } 434 435 436 437 438 439 440 441 442 443