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(pcis->vec1_N,counter,ADD_VALUES,SCATTER_REVERSE,matis->ctx);CHKERRQ(ierr); 41 ierr = VecScatterEnd (pcis->vec1_N,counter,ADD_VALUES,SCATTER_REVERSE,matis->ctx);CHKERRQ(ierr); 42 ierr = VecScatterBegin(counter,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD,matis->ctx);CHKERRQ(ierr); 43 ierr = VecScatterEnd (counter,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD,matis->ctx);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->vec1_N,pcis->D,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);CHKERRQ(ierr); 117 ierr = VecScatterEnd (pcis->vec1_N,pcis->D,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);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 = KSPSetOperators(pcis->ksp_D,pcis->A_II,pcis->A_II,SAME_PRECONDITIONER);CHKERRQ(ierr); 130 ierr = KSPSetOptionsPrefix(pcis->ksp_D,"is_localD_");CHKERRQ(ierr); 131 ierr = KSPGetPC(pcis->ksp_D,&pc_ctx);CHKERRQ(ierr); 132 ierr = PCSetType(pc_ctx,PCLU);CHKERRQ(ierr); 133 ierr = KSPSetType(pcis->ksp_D,KSPPREONLY);CHKERRQ(ierr); 134 ierr = KSPSetFromOptions(pcis->ksp_D);CHKERRQ(ierr); 135 /* the vectors in the following line are dummy arguments, just telling the KSP the vector size. Values are not used */ 136 ierr = KSPSetUp(pcis->ksp_D);CHKERRQ(ierr); 137 /* Neumann */ 138 ierr = KSPCreate(PETSC_COMM_SELF,&pcis->ksp_N);CHKERRQ(ierr); 139 ierr = KSPSetOperators(pcis->ksp_N,matis->A,matis->A,SAME_PRECONDITIONER);CHKERRQ(ierr); 140 ierr = KSPSetOptionsPrefix(pcis->ksp_N,"is_localN_");CHKERRQ(ierr); 141 ierr = KSPGetPC(pcis->ksp_N,&pc_ctx);CHKERRQ(ierr); 142 ierr = PCSetType(pc_ctx,PCLU);CHKERRQ(ierr); 143 ierr = KSPSetType(pcis->ksp_N,KSPPREONLY);CHKERRQ(ierr); 144 ierr = KSPSetFromOptions(pcis->ksp_N);CHKERRQ(ierr); 145 { 146 PetscTruth damp_fixed, 147 remove_nullspace_fixed, 148 set_damping_factor_floating, 149 not_damp_floating, 150 not_remove_nullspace_floating; 151 PetscReal fixed_factor, 152 floating_factor; 153 154 ierr = PetscOptionsGetReal(pc_ctx->prefix,"-pc_is_damp_fixed",&fixed_factor,&damp_fixed);CHKERRQ(ierr); 155 if (!damp_fixed) { fixed_factor = 0.0; } 156 ierr = PetscOptionsHasName(pc_ctx->prefix,"-pc_is_damp_fixed",&damp_fixed);CHKERRQ(ierr); 157 158 ierr = PetscOptionsHasName(pc_ctx->prefix,"-pc_is_remove_nullspace_fixed",&remove_nullspace_fixed);CHKERRQ(ierr); 159 160 ierr = PetscOptionsGetReal(pc_ctx->prefix,"-pc_is_set_damping_factor_floating", 161 &floating_factor,&set_damping_factor_floating);CHKERRQ(ierr); 162 if (!set_damping_factor_floating) { floating_factor = 0.0; } 163 ierr = PetscOptionsHasName(pc_ctx->prefix,"-pc_is_set_damping_factor_floating",&set_damping_factor_floating);CHKERRQ(ierr); 164 if (!set_damping_factor_floating) { floating_factor = 1.e-12; } 165 166 ierr = PetscOptionsHasName(pc_ctx->prefix,"-pc_is_not_damp_floating",¬_damp_floating);CHKERRQ(ierr); 167 168 ierr = PetscOptionsHasName(pc_ctx->prefix,"-pc_is_not_remove_nullspace_floating",¬_remove_nullspace_floating);CHKERRQ(ierr); 169 170 if (pcis->pure_neumann) { /* floating subdomain */ 171 if (!(not_damp_floating)) { 172 ierr = PCFactorSetShiftNonzero(pc_ctx,floating_factor);CHKERRQ(ierr); 173 } 174 if (!(not_remove_nullspace_floating)){ 175 MatNullSpace nullsp; 176 ierr = MatNullSpaceCreate(PETSC_COMM_SELF,PETSC_TRUE,0,PETSC_NULL,&nullsp);CHKERRQ(ierr); 177 ierr = KSPSetNullSpace(pcis->ksp_N,nullsp);CHKERRQ(ierr); 178 ierr = MatNullSpaceDestroy(nullsp);CHKERRQ(ierr); 179 } 180 } else { /* fixed subdomain */ 181 if (damp_fixed) { 182 ierr = PCFactorSetShiftNonzero(pc_ctx,fixed_factor);CHKERRQ(ierr); 183 } 184 if (remove_nullspace_fixed) { 185 MatNullSpace nullsp; 186 ierr = MatNullSpaceCreate(PETSC_COMM_SELF,PETSC_TRUE,0,PETSC_NULL,&nullsp);CHKERRQ(ierr); 187 ierr = KSPSetNullSpace(pcis->ksp_N,nullsp);CHKERRQ(ierr); 188 ierr = MatNullSpaceDestroy(nullsp);CHKERRQ(ierr); 189 } 190 } 191 } 192 /* the vectors in the following line are dummy arguments, just telling the KSP the vector size. Values are not used */ 193 ierr = KSPSetUp(pcis->ksp_N);CHKERRQ(ierr); 194 } 195 196 ierr = ISLocalToGlobalMappingGetInfo(((Mat_IS*)(pc->mat->data))->mapping,&(pcis->n_neigh),&(pcis->neigh),&(pcis->n_shared),&(pcis->shared));CHKERRQ(ierr); 197 pcis->ISLocalToGlobalMappingGetInfoWasCalled = PETSC_TRUE; 198 PetscFunctionReturn(0); 199 } 200 201 /* -------------------------------------------------------------------------- */ 202 /* 203 PCISDestroy - 204 */ 205 #undef __FUNCT__ 206 #define __FUNCT__ "PCISDestroy" 207 PetscErrorCode PETSCKSP_DLLEXPORT PCISDestroy(PC pc) 208 { 209 PC_IS *pcis = (PC_IS*)(pc->data); 210 PetscErrorCode ierr; 211 212 PetscFunctionBegin; 213 if (pcis->is_B_local) {ierr = ISDestroy(pcis->is_B_local);CHKERRQ(ierr);} 214 if (pcis->is_I_local) {ierr = ISDestroy(pcis->is_I_local);CHKERRQ(ierr);} 215 if (pcis->is_B_global) {ierr = ISDestroy(pcis->is_B_global);CHKERRQ(ierr);} 216 if (pcis->is_I_global) {ierr = ISDestroy(pcis->is_I_global);CHKERRQ(ierr);} 217 if (pcis->A_II) {ierr = MatDestroy(pcis->A_II);CHKERRQ(ierr);} 218 if (pcis->A_IB) {ierr = MatDestroy(pcis->A_IB);CHKERRQ(ierr);} 219 if (pcis->A_BI) {ierr = MatDestroy(pcis->A_BI);CHKERRQ(ierr);} 220 if (pcis->A_BB) {ierr = MatDestroy(pcis->A_BB);CHKERRQ(ierr);} 221 if (pcis->D) {ierr = VecDestroy(pcis->D);CHKERRQ(ierr);} 222 if (pcis->ksp_N) {ierr = KSPDestroy(pcis->ksp_N);CHKERRQ(ierr);} 223 if (pcis->ksp_D) {ierr = KSPDestroy(pcis->ksp_D);CHKERRQ(ierr);} 224 if (pcis->vec1_N) {ierr = VecDestroy(pcis->vec1_N);CHKERRQ(ierr);} 225 if (pcis->vec2_N) {ierr = VecDestroy(pcis->vec2_N);CHKERRQ(ierr);} 226 if (pcis->vec1_D) {ierr = VecDestroy(pcis->vec1_D);CHKERRQ(ierr);} 227 if (pcis->vec2_D) {ierr = VecDestroy(pcis->vec2_D);CHKERRQ(ierr);} 228 if (pcis->vec3_D) {ierr = VecDestroy(pcis->vec3_D);CHKERRQ(ierr);} 229 if (pcis->vec1_B) {ierr = VecDestroy(pcis->vec1_B);CHKERRQ(ierr);} 230 if (pcis->vec2_B) {ierr = VecDestroy(pcis->vec2_B);CHKERRQ(ierr);} 231 if (pcis->vec3_B) {ierr = VecDestroy(pcis->vec3_B);CHKERRQ(ierr);} 232 if (pcis->vec1_global) {ierr = VecDestroy(pcis->vec1_global);CHKERRQ(ierr);} 233 if (pcis->work_N) {ierr = PetscFree(pcis->work_N);CHKERRQ(ierr);} 234 if (pcis->global_to_D) {ierr = VecScatterDestroy(pcis->global_to_D);CHKERRQ(ierr);} 235 if (pcis->N_to_B) {ierr = VecScatterDestroy(pcis->N_to_B);CHKERRQ(ierr);} 236 if (pcis->global_to_B) {ierr = VecScatterDestroy(pcis->global_to_B);CHKERRQ(ierr);} 237 if (pcis->ISLocalToGlobalMappingGetInfoWasCalled) { 238 ierr = ISLocalToGlobalMappingRestoreInfo((ISLocalToGlobalMapping)0,&(pcis->n_neigh),&(pcis->neigh),&(pcis->n_shared),&(pcis->shared));CHKERRQ(ierr); 239 } 240 PetscFunctionReturn(0); 241 } 242 243 /* -------------------------------------------------------------------------- */ 244 /* 245 PCISCreate - 246 */ 247 #undef __FUNCT__ 248 #define __FUNCT__ "PCISCreate" 249 PetscErrorCode PETSCKSP_DLLEXPORT PCISCreate(PC pc) 250 { 251 PC_IS *pcis = (PC_IS*)(pc->data); 252 253 PetscFunctionBegin; 254 pcis->is_B_local = 0; 255 pcis->is_I_local = 0; 256 pcis->is_B_global = 0; 257 pcis->is_I_global = 0; 258 pcis->A_II = 0; 259 pcis->A_IB = 0; 260 pcis->A_BI = 0; 261 pcis->A_BB = 0; 262 pcis->D = 0; 263 pcis->ksp_N = 0; 264 pcis->ksp_D = 0; 265 pcis->vec1_N = 0; 266 pcis->vec2_N = 0; 267 pcis->vec1_D = 0; 268 pcis->vec2_D = 0; 269 pcis->vec3_D = 0; 270 pcis->vec1_B = 0; 271 pcis->vec2_B = 0; 272 pcis->vec3_B = 0; 273 pcis->vec1_global = 0; 274 pcis->work_N = 0; 275 pcis->global_to_D = 0; 276 pcis->N_to_B = 0; 277 pcis->global_to_B = 0; 278 pcis->ISLocalToGlobalMappingGetInfoWasCalled = PETSC_FALSE; 279 PetscFunctionReturn(0); 280 } 281 282 /* -------------------------------------------------------------------------- */ 283 /* 284 PCISApplySchur - 285 286 Input parameters: 287 . pc - preconditioner context 288 . v - vector to which the Schur complement is to be applied (it is NOT modified inside this function, UNLESS vec2_B is null) 289 290 Output parameters: 291 . vec1_B - result of Schur complement applied to chunk 292 . vec2_B - garbage (used as work space), or null (and v is used as workspace) 293 . vec1_D - garbage (used as work space) 294 . vec2_D - garbage (used as work space) 295 296 */ 297 #undef __FUNCT__ 298 #define __FUNCT__ "PCIterSuApplySchur" 299 PetscErrorCode PETSCKSP_DLLEXPORT PCISApplySchur(PC pc, Vec v, Vec vec1_B, Vec vec2_B, Vec vec1_D, Vec vec2_D) 300 { 301 PetscErrorCode ierr; 302 PC_IS *pcis = (PC_IS*)(pc->data); 303 304 PetscFunctionBegin; 305 if (!vec2_B) { vec2_B = v; } 306 307 ierr = MatMult(pcis->A_BB,v,vec1_B);CHKERRQ(ierr); 308 ierr = MatMult(pcis->A_IB,v,vec1_D);CHKERRQ(ierr); 309 ierr = KSPSolve(pcis->ksp_D,vec1_D,vec2_D);CHKERRQ(ierr); 310 ierr = MatMult(pcis->A_BI,vec2_D,vec2_B);CHKERRQ(ierr); 311 ierr = VecAXPY(vec1_B,-1.0,vec2_B);CHKERRQ(ierr); 312 PetscFunctionReturn(0); 313 } 314 315 /* -------------------------------------------------------------------------- */ 316 /* 317 PCISScatterArrayNToVecB - Scatters interface node values from a big array (of all local nodes, interior or interface, 318 including ghosts) into an interface vector, when in SCATTER_FORWARD mode, or vice-versa, when in SCATTER_REVERSE 319 mode. 320 321 Input parameters: 322 . pc - preconditioner context 323 . array_N - [when in SCATTER_FORWARD mode] Array to be scattered into the vector 324 . v_B - [when in SCATTER_REVERSE mode] Vector to be scattered into the array 325 326 Output parameter: 327 . array_N - [when in SCATTER_REVERSE mode] Array to receive the scattered vector 328 . v_B - [when in SCATTER_FORWARD mode] Vector to receive the scattered array 329 330 Notes: 331 The entries in the array that do not correspond to interface nodes remain unaltered. 332 */ 333 #undef __FUNCT__ 334 #define __FUNCT__ "PCISScatterArrayNToVecB" 335 PetscErrorCode PETSCKSP_DLLEXPORT PCISScatterArrayNToVecB (PetscScalar *array_N, Vec v_B, InsertMode imode, ScatterMode smode, PC pc) 336 { 337 PetscInt i, *idex; 338 PetscErrorCode ierr; 339 PetscScalar *array_B; 340 PC_IS *pcis = (PC_IS*)(pc->data); 341 342 PetscFunctionBegin; 343 ierr = VecGetArray(v_B,&array_B);CHKERRQ(ierr); 344 ierr = ISGetIndices(pcis->is_B_local,&idex);CHKERRQ(ierr); 345 346 if (smode == SCATTER_FORWARD) { 347 if (imode == INSERT_VALUES) { 348 for (i=0; i<pcis->n_B; i++) { array_B[i] = array_N[idex[i]]; } 349 } else { /* ADD_VALUES */ 350 for (i=0; i<pcis->n_B; i++) { array_B[i] += array_N[idex[i]]; } 351 } 352 } else { /* SCATTER_REVERSE */ 353 if (imode == INSERT_VALUES) { 354 for (i=0; i<pcis->n_B; i++) { array_N[idex[i]] = array_B[i]; } 355 } else { /* ADD_VALUES */ 356 for (i=0; i<pcis->n_B; i++) { array_N[idex[i]] += array_B[i]; } 357 } 358 } 359 ierr = ISRestoreIndices(pcis->is_B_local,&idex);CHKERRQ(ierr); 360 ierr = VecRestoreArray(v_B,&array_B);CHKERRQ(ierr); 361 PetscFunctionReturn(0); 362 } 363 364 /* -------------------------------------------------------------------------- */ 365 /* 366 PCISApplyInvSchur - Solves the Neumann problem related to applying the inverse of the Schur complement. 367 More precisely, solves the problem: 368 [ A_II A_IB ] [ . ] [ 0 ] 369 [ ] [ ] = [ ] 370 [ A_BI A_BB ] [ x ] [ b ] 371 372 Input parameters: 373 . pc - preconditioner context 374 . b - vector of local interface nodes (including ghosts) 375 376 Output parameters: 377 . x - vector of local interface nodes (including ghosts); returns the application of the inverse of the Schur 378 complement to b 379 . vec1_N - vector of local nodes (interior and interface, including ghosts); returns garbage (used as work space) 380 . vec2_N - vector of local nodes (interior and interface, including ghosts); returns garbage (used as work space) 381 382 */ 383 #undef __FUNCT__ 384 #define __FUNCT__ "PCISApplyInvSchur" 385 PetscErrorCode PETSCKSP_DLLEXPORT PCISApplyInvSchur (PC pc, Vec b, Vec x, Vec vec1_N, Vec vec2_N) 386 { 387 PetscErrorCode ierr; 388 PC_IS *pcis = (PC_IS*)(pc->data); 389 390 PetscFunctionBegin; 391 /* 392 Neumann solvers. 393 Applying the inverse of the local Schur complement, i.e, solving a Neumann 394 Problem with zero at the interior nodes of the RHS and extracting the interface 395 part of the solution. inverse Schur complement is applied to b and the result 396 is stored in x. 397 */ 398 /* Setting the RHS vec1_N */ 399 ierr = VecSet(vec1_N,0.0);CHKERRQ(ierr); 400 ierr = VecScatterBegin(b,vec1_N,INSERT_VALUES,SCATTER_REVERSE,pcis->N_to_B);CHKERRQ(ierr); 401 ierr = VecScatterEnd (b,vec1_N,INSERT_VALUES,SCATTER_REVERSE,pcis->N_to_B);CHKERRQ(ierr); 402 /* Checking for consistency of the RHS */ 403 { 404 PetscTruth flg; 405 ierr = PetscOptionsHasName(PETSC_NULL,"-pc_is_check_consistency",&flg);CHKERRQ(ierr); 406 if (flg) { 407 PetscScalar average; 408 ierr = VecSum(vec1_N,&average);CHKERRQ(ierr); 409 average = average / ((PetscReal)pcis->n); 410 if (pcis->pure_neumann) { 411 ierr = PetscViewerASCIISynchronizedPrintf(PETSC_VIEWER_STDOUT_(pc->comm),"Subdomain %04d is floating. Average = % 1.14e\n", 412 PetscGlobalRank,PetscAbsScalar(average));CHKERRQ(ierr); 413 } else { 414 ierr = PetscViewerASCIISynchronizedPrintf(PETSC_VIEWER_STDOUT_(pc->comm),"Subdomain %04d is fixed. Average = % 1.14e\n", 415 PetscGlobalRank,PetscAbsScalar(average));CHKERRQ(ierr); 416 } 417 PetscViewerFlush(PETSC_VIEWER_STDOUT_(pc->comm)); 418 } 419 } 420 /* Solving the system for vec2_N */ 421 ierr = KSPSolve(pcis->ksp_N,vec1_N,vec2_N);CHKERRQ(ierr); 422 /* Extracting the local interface vector out of the solution */ 423 ierr = VecScatterBegin(vec2_N,x,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);CHKERRQ(ierr); 424 ierr = VecScatterEnd (vec2_N,x,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);CHKERRQ(ierr); 425 PetscFunctionReturn(0); 426 } 427 428 429 430 431 432 433 434 435 436