Date: 2016-07-24T17:04:18+00:00

Actual source code: tfs.c
petsc-3.7.3 2016-07-24
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      1: /*
      2:         Provides an interface to the Tufo-Fischer parallel direct solver
      3: */

      5: #include <petsc/private/pcimpl.h>   /*I "petscpc.h" I*/
      6: #include <../src/mat/impls/aij/mpi/mpiaij.h>
      7: #include <../src/ksp/pc/impls/tfs/tfs.h>

      9: typedef struct {
     10:   xxt_ADT  xxt;
     11:   xyt_ADT  xyt;
     12:   Vec      b,xd,xo;
     13:   PetscInt nd;
     14: } PC_TFS;

     18: PetscErrorCode PCDestroy_TFS(PC pc)
     19: {
     20:   PC_TFS         *tfs = (PC_TFS*)pc->data;

     24:   /* free the XXT datastructures */
     25:   if (tfs->xxt) {
     26:     XXT_free(tfs->xxt);
     27:   }
     28:   if (tfs->xyt) {
     29:     XYT_free(tfs->xyt);
     30:   }
     31:   VecDestroy(&tfs->b);
     32:   VecDestroy(&tfs->xd);
     33:   VecDestroy(&tfs->xo);
     34:   PetscFree(pc->data);
     35:   return(0);
     36: }

     40: static PetscErrorCode PCApply_TFS_XXT(PC pc,Vec x,Vec y)
     41: {
     42:   PC_TFS         *tfs = (PC_TFS*)pc->data;
     43:   PetscScalar    *xx,*yy;

     47:   VecGetArray(x,&xx);
     48:   VecGetArray(y,&yy);
     49:   XXT_solve(tfs->xxt,yy,xx);
     50:   VecRestoreArray(x,&xx);
     51:   VecRestoreArray(y,&yy);
     52:   return(0);
     53: }

     57: static PetscErrorCode PCApply_TFS_XYT(PC pc,Vec x,Vec y)
     58: {
     59:   PC_TFS         *tfs = (PC_TFS*)pc->data;
     60:   PetscScalar    *xx,*yy;

     64:   VecGetArray(x,&xx);
     65:   VecGetArray(y,&yy);
     66:   XYT_solve(tfs->xyt,yy,xx);
     67:   VecRestoreArray(x,&xx);
     68:   VecRestoreArray(y,&yy);
     69:   return(0);
     70: }

     74: static PetscErrorCode PCTFSLocalMult_TFS(PC pc,PetscScalar *xin,PetscScalar *xout)
     75: {
     76:   PC_TFS         *tfs = (PC_TFS*)pc->data;
     77:   Mat            A    = pc->pmat;
     78:   Mat_MPIAIJ     *a   = (Mat_MPIAIJ*)A->data;

     82:   VecPlaceArray(tfs->b,xout);
     83:   VecPlaceArray(tfs->xd,xin);
     84:   VecPlaceArray(tfs->xo,xin+tfs->nd);
     85:   MatMult(a->A,tfs->xd,tfs->b);
     86:   MatMultAdd(a->B,tfs->xo,tfs->b,tfs->b);
     87:   VecResetArray(tfs->b);
     88:   VecResetArray(tfs->xd);
     89:   VecResetArray(tfs->xo);
     90:   return(0);
     91: }

     95: static PetscErrorCode PCSetUp_TFS(PC pc)
     96: {
     97:   PC_TFS         *tfs = (PC_TFS*)pc->data;
     98:   Mat            A    = pc->pmat;
     99:   Mat_MPIAIJ     *a   = (Mat_MPIAIJ*)A->data;
    101:   PetscInt       *localtoglobal,ncol,i;
    102:   PetscBool      ismpiaij;

    104:   /*
    105:   PetscBool      issymmetric;
    106:   Petsc Real tol = 0.0;
    107:   */

    110:   if (A->cmap->N != A->rmap->N) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_SIZ,"matrix must be square");
    111:   PetscObjectTypeCompare((PetscObject)pc->pmat,MATMPIAIJ,&ismpiaij);
    112:   if (!ismpiaij) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Currently only supports MPIAIJ matrices");

    114:   /* generate the local to global mapping */
    115:   ncol = a->A->cmap->n + a->B->cmap->n;
    116:   PetscMalloc1(ncol,&localtoglobal);
    117:   for (i=0; i<a->A->cmap->n; i++) localtoglobal[i] = A->cmap->rstart + i + 1;
    118:   for (i=0; i<a->B->cmap->n; i++) localtoglobal[i+a->A->cmap->n] = a->garray[i] + 1;

    120:   /* generate the vectors needed for the local solves */
    121:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,a->A->rmap->n,NULL,&tfs->b);
    122:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,a->A->cmap->n,NULL,&tfs->xd);
    123:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,a->B->cmap->n,NULL,&tfs->xo);
    124:   tfs->nd = a->A->cmap->n;

    127:   /*   MatIsSymmetric(A,tol,&issymmetric); */
    128:   /*  if (issymmetric) { */
    129:   PetscBarrier((PetscObject)pc);
    130:   if (A->symmetric) {
    131:     tfs->xxt       = XXT_new();
    132:     XXT_factor(tfs->xxt,localtoglobal,A->rmap->n,ncol,(PetscErrorCode (*)(void*,PetscScalar*,PetscScalar*))PCTFSLocalMult_TFS,pc);
    133:     pc->ops->apply = PCApply_TFS_XXT;
    134:   } else {
    135:     tfs->xyt       = XYT_new();
    136:     XYT_factor(tfs->xyt,localtoglobal,A->rmap->n,ncol,(PetscErrorCode (*)(void*,PetscScalar*,PetscScalar*))PCTFSLocalMult_TFS,pc);
    137:     pc->ops->apply = PCApply_TFS_XYT;
    138:   }

    140:   PetscFree(localtoglobal);
    141:   return(0);
    142: }

    146: static PetscErrorCode PCSetFromOptions_TFS(PetscOptionItems *PetscOptionsObject,PC pc)
    147: {
    149:   return(0);
    150: }
    153: static PetscErrorCode PCView_TFS(PC pc,PetscViewer viewer)
    154: {
    156:   return(0);
    157: }

    161: /*MC
    162:      PCTFS - A parallel direct solver intended for problems with very few unknowns (like the
    163:          coarse grid in multigrid).

    165:    Implemented by  Henry M. Tufo III and Paul Fischer

    167:    Level: beginner

    169:    Notes: Only implemented for the MPIAIJ matrices

    171:           Only works on a solver object that lives on all of PETSC_COMM_WORLD!

    173: .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC
    174: M*/
    175: PETSC_EXTERN PetscErrorCode PCCreate_TFS(PC pc)
    176: {
    178:   PC_TFS         *tfs;
    179:   PetscMPIInt    cmp;

    182:   MPI_Comm_compare(PETSC_COMM_WORLD,PetscObjectComm((PetscObject)pc),&cmp);
    183:   if (cmp != MPI_IDENT && cmp != MPI_CONGRUENT) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"TFS only works with PETSC_COMM_WORLD objects");
    184:   PetscNewLog(pc,&tfs);

    186:   tfs->xxt = 0;
    187:   tfs->xyt = 0;
    188:   tfs->b   = 0;
    189:   tfs->xd  = 0;
    190:   tfs->xo  = 0;
    191:   tfs->nd  = 0;

    193:   pc->ops->apply               = 0;
    194:   pc->ops->applytranspose      = 0;
    195:   pc->ops->setup               = PCSetUp_TFS;
    196:   pc->ops->destroy             = PCDestroy_TFS;
    197:   pc->ops->setfromoptions      = PCSetFromOptions_TFS;
    198:   pc->ops->view                = PCView_TFS;
    199:   pc->ops->applyrichardson     = 0;
    200:   pc->ops->applysymmetricleft  = 0;
    201:   pc->ops->applysymmetricright = 0;
    202:   pc->data                     = (void*)tfs;
    203:   return(0);
    204: }