Date: 2024-12-02T08:57:56+00:00

Actual source code: slepccontour.c
slepc-3.22.2 2024-12-02
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.
      7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: */

     11: #include <slepc/private/slepccontour.h>
     12: #include <slepcblaslapack.h>

     14: /*
     15:    SlepcContourDataCreate - Create a contour data structure.

     17:    Input Parameters:
     18:    n - the number of integration points
     19:    npart - number of partitions for the subcommunicator
     20:    parent - parent object
     21: */
     22: PetscErrorCode SlepcContourDataCreate(PetscInt n,PetscInt npart,PetscObject parent,SlepcContourData *contour)
     23: {
     24:   PetscFunctionBegin;
     25:   PetscCall(PetscNew(contour));
     26:   (*contour)->parent = parent;
     27:   PetscCall(PetscSubcommCreate(PetscObjectComm(parent),&(*contour)->subcomm));
     28:   PetscCall(PetscSubcommSetNumber((*contour)->subcomm,npart));
     29:   PetscCall(PetscSubcommSetType((*contour)->subcomm,PETSC_SUBCOMM_INTERLACED));
     30:   (*contour)->npoints = n / npart;
     31:   if (n%npart > (*contour)->subcomm->color) (*contour)->npoints++;
     32:   PetscFunctionReturn(PETSC_SUCCESS);
     33: }

     35: /*
     36:    SlepcContourDataReset - Resets the KSP objects in a contour data structure,
     37:    and destroys any objects whose size depends on the problem size.
     38: */
     39: PetscErrorCode SlepcContourDataReset(SlepcContourData contour)
     40: {
     41:   PetscInt       i;

     43:   PetscFunctionBegin;
     44:   if (contour->ksp) {
     45:     for (i=0;i<contour->npoints;i++) PetscCall(KSPReset(contour->ksp[i]));
     46:   }
     47:   if (contour->pA) {
     48:     PetscCall(MatDestroyMatrices(contour->nmat,&contour->pA));
     49:     PetscCall(MatDestroyMatrices(contour->nmat,&contour->pP));
     50:     contour->nmat = 0;
     51:   }
     52:   PetscCall(VecScatterDestroy(&contour->scatterin));
     53:   PetscCall(VecDestroy(&contour->xsub));
     54:   PetscCall(VecDestroy(&contour->xdup));
     55:   PetscFunctionReturn(PETSC_SUCCESS);
     56: }

     58: /*
     59:    SlepcContourDataDestroy - Destroys the contour data structure.
     60: */
     61: PetscErrorCode SlepcContourDataDestroy(SlepcContourData *contour)
     62: {
     63:   PetscInt       i;

     65:   PetscFunctionBegin;
     66:   if (!(*contour)) PetscFunctionReturn(PETSC_SUCCESS);
     67:   if ((*contour)->ksp) {
     68:     for (i=0;i<(*contour)->npoints;i++) PetscCall(KSPDestroy(&(*contour)->ksp[i]));
     69:     PetscCall(PetscFree((*contour)->ksp));
     70:   }
     71:   PetscCall(PetscSubcommDestroy(&(*contour)->subcomm));
     72:   PetscCall(PetscFree((*contour)));
     73:   *contour = NULL;
     74:   PetscFunctionReturn(PETSC_SUCCESS);
     75: }

     77: /*
     78:    SlepcContourRedundantMat - Creates redundant copies of the passed matrices in the subcomm.

     80:    Input Parameters:
     81:    nmat - the number of matrices
     82:    A    - array of matrices
     83:    P    - array of matrices (preconditioner)
     84: */
     85: PetscErrorCode SlepcContourRedundantMat(SlepcContourData contour,PetscInt nmat,Mat *A,Mat *P)
     86: {
     87:   PetscInt       i;
     88:   MPI_Comm       child;

     90:   PetscFunctionBegin;
     91:   if (contour->pA) {
     92:     PetscCall(MatDestroyMatrices(contour->nmat,&contour->pA));
     93:     PetscCall(MatDestroyMatrices(contour->nmat,&contour->pP));
     94:     contour->nmat = 0;
     95:   }
     96:   if (contour->subcomm && contour->subcomm->n != 1) {
     97:     PetscCall(PetscSubcommGetChild(contour->subcomm,&child));
     98:     PetscCall(PetscCalloc1(nmat,&contour->pA));
     99:     for (i=0;i<nmat;i++) PetscCall(MatCreateRedundantMatrix(A[i],contour->subcomm->n,child,MAT_INITIAL_MATRIX,&contour->pA[i]));
    100:     if (P) {
    101:       PetscCall(PetscCalloc1(nmat,&contour->pP));
    102:       for (i=0;i<nmat;i++) PetscCall(MatCreateRedundantMatrix(P[i],contour->subcomm->n,child,MAT_INITIAL_MATRIX,&contour->pP[i]));
    103:     }
    104:     contour->nmat = nmat;
    105:   }
    106:   PetscFunctionReturn(PETSC_SUCCESS);
    107: }

    109: /*
    110:    SlepcContourScatterCreate - Creates a scatter context to communicate between a
    111:    regular vector and a vector xdup that can hold one duplicate per each subcommunicator
    112:    on the contiguous parent communicator. Also creates auxiliary vectors xdup and xsub
    113:    (the latter with the same layout as the redundant matrices in the subcommunicator).

    115:    Input Parameters:
    116:    v - the regular vector from which dimensions are taken
    117: */
    118: PetscErrorCode SlepcContourScatterCreate(SlepcContourData contour,Vec v)
    119: {
    120:   IS             is1,is2;
    121:   PetscInt       i,j,k,m,mstart,mend,mlocal;
    122:   PetscInt       *idx1,*idx2,mloc_sub;
    123:   MPI_Comm       contpar,parent;

    125:   PetscFunctionBegin;
    126:   PetscCall(VecDestroy(&contour->xsub));
    127:   PetscCall(MatCreateVecsEmpty(contour->pA[0],&contour->xsub,NULL));

    129:   PetscCall(VecDestroy(&contour->xdup));
    130:   PetscCall(MatGetLocalSize(contour->pA[0],&mloc_sub,NULL));
    131:   PetscCall(PetscSubcommGetContiguousParent(contour->subcomm,&contpar));
    132:   PetscCall(VecCreate(contpar,&contour->xdup));
    133:   PetscCall(VecSetSizes(contour->xdup,mloc_sub,PETSC_DECIDE));
    134:   PetscCall(VecSetType(contour->xdup,((PetscObject)v)->type_name));

    136:   PetscCall(VecScatterDestroy(&contour->scatterin));
    137:   PetscCall(VecGetSize(v,&m));
    138:   PetscCall(VecGetOwnershipRange(v,&mstart,&mend));
    139:   mlocal = mend - mstart;
    140:   PetscCall(PetscMalloc2(contour->subcomm->n*mlocal,&idx1,contour->subcomm->n*mlocal,&idx2));
    141:   j = 0;
    142:   for (k=0;k<contour->subcomm->n;k++) {
    143:     for (i=mstart;i<mend;i++) {
    144:       idx1[j]   = i;
    145:       idx2[j++] = i + m*k;
    146:     }
    147:   }
    148:   PetscCall(PetscSubcommGetParent(contour->subcomm,&parent));
    149:   PetscCall(ISCreateGeneral(parent,contour->subcomm->n*mlocal,idx1,PETSC_COPY_VALUES,&is1));
    150:   PetscCall(ISCreateGeneral(parent,contour->subcomm->n*mlocal,idx2,PETSC_COPY_VALUES,&is2));
    151:   PetscCall(VecScatterCreate(v,is1,contour->xdup,is2,&contour->scatterin));
    152:   PetscCall(ISDestroy(&is1));
    153:   PetscCall(ISDestroy(&is2));
    154:   PetscCall(PetscFree2(idx1,idx2));
    155:   PetscFunctionReturn(PETSC_SUCCESS);
    156: }

    158: /*
    159:    SlepcCISS_isGhost - Determine if any of the computed eigenpairs are spurious.

    161:    Input Parameters:
    162:    X - the matrix of eigenvectors (MATSEQDENSE)
    163:    n - the number of columns to consider
    164:    sigma - the singular values
    165:    thresh - threshold to decide whether a value is spurious

    167:    Output Parameter:
    168:    fl - array of n booleans
    169: */
    170: PetscErrorCode SlepcCISS_isGhost(Mat X,PetscInt n,PetscReal *sigma,PetscReal thresh,PetscBool *fl)
    171: {
    172:   const PetscScalar *pX;
    173:   PetscInt          i,j,m,ld;
    174:   PetscReal         *tau,s1,s2,tau_max=0.0;

    176:   PetscFunctionBegin;
    177:   PetscCall(MatGetSize(X,&m,NULL));
    178:   PetscCall(MatDenseGetLDA(X,&ld));
    179:   PetscCall(PetscMalloc1(n,&tau));
    180:   PetscCall(MatDenseGetArrayRead(X,&pX));
    181:   for (j=0;j<n;j++) {
    182:     s1 = 0.0;
    183:     s2 = 0.0;
    184:     for (i=0;i<m;i++) {
    185:       s1 += PetscAbsScalar(PetscPowScalarInt(pX[i+j*ld],2));
    186:       s2 += PetscPowRealInt(PetscAbsScalar(pX[i+j*ld]),2)/sigma[i];
    187:     }
    188:     tau[j] = s1/s2;
    189:     tau_max = PetscMax(tau_max,tau[j]);
    190:   }
    191:   PetscCall(MatDenseRestoreArrayRead(X,&pX));
    192:   for (j=0;j<n;j++) fl[j] = (tau[j]>=thresh*tau_max)? PETSC_TRUE: PETSC_FALSE;
    193:   PetscCall(PetscFree(tau));
    194:   PetscFunctionReturn(PETSC_SUCCESS);
    195: }

    197: /*
    198:    SlepcCISS_BH_SVD - Compute SVD of block Hankel matrix and its rank.

    200:    Input Parameters:
    201:    H  - block Hankel matrix obtained via CISS_BlockHankel()
    202:    ml - dimension of rows and columns, equal to M*L
    203:    delta - the tolerance used to determine the rank

    205:    Output Parameters:
    206:    sigma - computed singular values
    207:    rank  - the rank of H
    208: */
    209: PetscErrorCode SlepcCISS_BH_SVD(PetscScalar *H,PetscInt ml,PetscReal delta,PetscReal *sigma,PetscInt *rank)
    210: {
    211:   PetscInt       i;
    212:   PetscBLASInt   m,n,lda,ldu,ldvt,lwork,info;
    213:   PetscScalar    *work;
    214: #if defined(PETSC_USE_COMPLEX)
    215:   PetscReal      *rwork;
    216: #endif

    218:   PetscFunctionBegin;
    219:   PetscCall(PetscMalloc1(5*ml,&work));
    220: #if defined(PETSC_USE_COMPLEX)
    221:   PetscCall(PetscMalloc1(5*ml,&rwork));
    222: #endif
    223:   PetscCall(PetscBLASIntCast(ml,&m));
    224:   n = m; lda = m; ldu = m; ldvt = m; lwork = 5*m;
    225:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
    226: #if defined(PETSC_USE_COMPLEX)
    227:   PetscCallBLAS("LAPACKgesvd",LAPACKgesvd_("N","N",&m,&n,H,&lda,sigma,NULL,&ldu,NULL,&ldvt,work,&lwork,rwork,&info));
    228: #else
    229:   PetscCallBLAS("LAPACKgesvd",LAPACKgesvd_("N","N",&m,&n,H,&lda,sigma,NULL,&ldu,NULL,&ldvt,work,&lwork,&info));
    230: #endif
    231:   SlepcCheckLapackInfo("gesvd",info);
    232:   PetscCall(PetscFPTrapPop());
    233:   (*rank) = 0;
    234:   for (i=0;i<ml;i++) {
    235:     if (sigma[i]/PetscMax(sigma[0],1.0)>delta) (*rank)++;
    236:   }
    237:   PetscCall(PetscFree(work));
    238: #if defined(PETSC_USE_COMPLEX)
    239:   PetscCall(PetscFree(rwork));
    240: #endif
    241:   PetscFunctionReturn(PETSC_SUCCESS);
    242: }