1 2 #include "src/ksp/pc/impls/is/pcis.h" 3 4 /* -------------------------------------------------------------------------- */ 5 /* 6 PCISSetUp - 7 */ 8 #undef __FUNCT__ 9 #define __FUNCT__ "PCISSetUp" 10 PetscErrorCode PCISSetUp(PC pc) 11 { 12 PC_IS *pcis = (PC_IS*)(pc->data); 13 Mat_IS *matis = (Mat_IS*)pc->mat->data; 14 PetscInt i; 15 PetscErrorCode ierr; 16 PetscTruth flg; 17 18 PetscFunctionBegin; 19 ierr = PetscTypeCompare((PetscObject)pc->mat,MATIS,&flg);CHKERRQ(ierr); 20 if (!flg){ 21 SETERRQ(PETSC_ERR_ARG_WRONG,"Preconditioner type of Neumann Neumman requires matrix of type MATIS"); 22 } 23 24 pcis->pure_neumann = matis->pure_neumann; 25 26 /* 27 Creating the local vector vec1_N, containing the inverse of the number 28 of subdomains to which each local node (either owned or ghost) 29 pertains. To accomplish that, we scatter local vectors of 1's to 30 a global vector (adding the values); scatter the result back to 31 local vectors and finally invert the result. 32 */ 33 { 34 Vec counter; 35 PetscScalar one=1.0, zero=0.0; 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(&zero,counter);CHKERRQ(ierr); 39 ierr = VecSet(&one,pcis->vec1_N);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 = PCLUSetDamping (pc_ctx,floating_factor);CHKERRQ(ierr); 173 ierr = PCILUSetDamping(pc_ctx,floating_factor);CHKERRQ(ierr); 174 } 175 if (!(not_remove_nullspace_floating)){ 176 MatNullSpace nullsp; 177 ierr = MatNullSpaceCreate(PETSC_COMM_SELF,PETSC_TRUE,0,PETSC_NULL,&nullsp);CHKERRQ(ierr); 178 ierr = KSPSetNullSpace(pcis->ksp_N,nullsp);CHKERRQ(ierr); 179 ierr = MatNullSpaceDestroy(nullsp);CHKERRQ(ierr); 180 } 181 } else { /* fixed subdomain */ 182 if (damp_fixed) { 183 ierr = PCLUSetDamping (pc_ctx,fixed_factor);CHKERRQ(ierr); 184 ierr = PCILUSetDamping(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 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->work_N) {ierr = PetscFree(pcis->work_N);CHKERRQ(ierr);} 236 if (pcis->global_to_D) {ierr = VecScatterDestroy(pcis->global_to_D);CHKERRQ(ierr);} 237 if (pcis->N_to_B) {ierr = VecScatterDestroy(pcis->N_to_B);CHKERRQ(ierr);} 238 if (pcis->global_to_B) {ierr = VecScatterDestroy(pcis->global_to_B);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 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 PCISApplySchur(PC pc, Vec v, Vec vec1_B, Vec vec2_B, Vec vec1_D, Vec vec2_D) 302 { 303 PetscErrorCode ierr; 304 PetscScalar m_one = -1.0; 305 PC_IS *pcis = (PC_IS*)(pc->data); 306 307 PetscFunctionBegin; 308 if (!vec2_B) { vec2_B = v; } 309 310 ierr = MatMult(pcis->A_BB,v,vec1_B);CHKERRQ(ierr); 311 ierr = MatMult(pcis->A_IB,v,vec1_D);CHKERRQ(ierr); 312 ierr = KSPSolve(pcis->ksp_D,vec1_D,vec2_D);CHKERRQ(ierr); 313 ierr = MatMult(pcis->A_BI,vec2_D,vec2_B);CHKERRQ(ierr); 314 ierr = VecAXPY(&m_one,vec2_B,vec1_B);CHKERRQ(ierr); 315 PetscFunctionReturn(0); 316 } 317 318 /* -------------------------------------------------------------------------- */ 319 /* 320 PCISScatterArrayNToVecB - Scatters interface node values from a big array (of all local nodes, interior or interface, 321 including ghosts) into an interface vector, when in SCATTER_FORWARD mode, or vice-versa, when in SCATTER_REVERSE 322 mode. 323 324 Input parameters: 325 . pc - preconditioner context 326 . array_N - [when in SCATTER_FORWARD mode] Array to be scattered into the vector 327 . v_B - [when in SCATTER_REVERSE mode] Vector to be scattered into the array 328 329 Output parameter: 330 . array_N - [when in SCATTER_REVERSE mode] Array to receive the scattered vector 331 . v_B - [when in SCATTER_FORWARD mode] Vector to receive the scattered array 332 333 Notes: 334 The entries in the array that do not correspond to interface nodes remain unaltered. 335 */ 336 #undef __FUNCT__ 337 #define __FUNCT__ "PCISScatterArrayNToVecB" 338 PetscErrorCode PCISScatterArrayNToVecB (PetscScalar *array_N, Vec v_B, InsertMode imode, ScatterMode smode, PC pc) 339 { 340 PetscInt i, *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 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 PetscScalar zero = 0.0; 393 394 PetscFunctionBegin; 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 ierr = VecSet(&zero,vec1_N);CHKERRQ(ierr); 404 ierr = VecScatterBegin(b,vec1_N,INSERT_VALUES,SCATTER_REVERSE,pcis->N_to_B);CHKERRQ(ierr); 405 ierr = VecScatterEnd (b,vec1_N,INSERT_VALUES,SCATTER_REVERSE,pcis->N_to_B);CHKERRQ(ierr); 406 /* Checking for consistency of the RHS */ 407 { 408 PetscTruth flg; 409 ierr = PetscOptionsHasName(PETSC_NULL,"-pc_is_check_consistency",&flg);CHKERRQ(ierr); 410 if (flg) { 411 PetscScalar average; 412 ierr = VecSum(vec1_N,&average);CHKERRQ(ierr); 413 average = average / ((PetscReal)pcis->n); 414 if (pcis->pure_neumann) { 415 ierr = PetscViewerASCIISynchronizedPrintf(PETSC_VIEWER_STDOUT_(pc->comm),"Subdomain %04d is floating. Average = % 1.14e\n", 416 PetscGlobalRank,PetscAbsScalar(average));CHKERRQ(ierr); 417 } else { 418 ierr = PetscViewerASCIISynchronizedPrintf(PETSC_VIEWER_STDOUT_(pc->comm),"Subdomain %04d is fixed. Average = % 1.14e\n", 419 PetscGlobalRank,PetscAbsScalar(average));CHKERRQ(ierr); 420 } 421 PetscViewerFlush(PETSC_VIEWER_STDOUT_(pc->comm)); 422 } 423 } 424 /* Solving the system for vec2_N */ 425 ierr = KSPSolve(pcis->ksp_N,vec1_N,vec2_N);CHKERRQ(ierr); 426 /* Extracting the local interface vector out of the solution */ 427 ierr = VecScatterBegin(vec2_N,x,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);CHKERRQ(ierr); 428 ierr = VecScatterEnd (vec2_N,x,INSERT_VALUES,SCATTER_FORWARD,pcis->N_to_B);CHKERRQ(ierr); 429 PetscFunctionReturn(0); 430 } 431 432 433 434 435 436 437 438 439 440