Date: 2026-05-01T10:02:04+00:00

Actual source code: test7.c

      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: static char help[] = "Test interface functions of spectrum-slicing STOAR.\n\n"
     12:   "This is based on ex38.c. The command line options are:\n"
     13:   "  -n <n> ... dimension of the matrices.\n\n";

     15: #include <slepcpep.h>

     17: int main(int argc,char **argv)
     18: {
     19:   Mat            M,C,K,A[3]; /* problem matrices */
     20:   PEP            pep;        /* polynomial eigenproblem solver context */
     21:   ST             st;         /* spectral transformation context */
     22:   KSP            ksp;
     23:   PC             pc;
     24:   PetscBool      showinertia=PETSC_TRUE,lock,detect,checket;
     25:   PetscInt       n=100,Istart,Iend,i,*inertias,ns,nev,ncv,mpd;
     26:   PetscReal      mu=1.0,tau=10.0,kappa=5.0,int0,int1,*shifts;

     28:   PetscFunctionBeginUser;
     29:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));

     31:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
     32:   PetscCall(PetscOptionsGetBool(NULL,NULL,"-showinertia",&showinertia,NULL));
     33:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nSpectrum slicing on PEP, n=%" PetscInt_FMT "\n\n",n));

     35:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     36:      Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
     37:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     39:   /* K is a tridiagonal */
     40:   PetscCall(MatCreate(PETSC_COMM_WORLD,&K));
     41:   PetscCall(MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,n,n));
     42:   PetscCall(MatSetFromOptions(K));

     44:   PetscCall(MatGetOwnershipRange(K,&Istart,&Iend));
     45:   for (i=Istart;i<Iend;i++) {
     46:     if (i>0) PetscCall(MatSetValue(K,i,i-1,-kappa,INSERT_VALUES));
     47:     PetscCall(MatSetValue(K,i,i,kappa*3.0,INSERT_VALUES));
     48:     if (i<n-1) PetscCall(MatSetValue(K,i,i+1,-kappa,INSERT_VALUES));
     49:   }

     51:   PetscCall(MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY));
     52:   PetscCall(MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY));

     54:   /* C is a tridiagonal */
     55:   PetscCall(MatCreate(PETSC_COMM_WORLD,&C));
     56:   PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,n,n));
     57:   PetscCall(MatSetFromOptions(C));

     59:   PetscCall(MatGetOwnershipRange(C,&Istart,&Iend));
     60:   for (i=Istart;i<Iend;i++) {
     61:     if (i>0) PetscCall(MatSetValue(C,i,i-1,-tau,INSERT_VALUES));
     62:     PetscCall(MatSetValue(C,i,i,tau*3.0,INSERT_VALUES));
     63:     if (i<n-1) PetscCall(MatSetValue(C,i,i+1,-tau,INSERT_VALUES));
     64:   }

     66:   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
     67:   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));

     69:   /* M is a diagonal matrix */
     70:   PetscCall(MatCreate(PETSC_COMM_WORLD,&M));
     71:   PetscCall(MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,n,n));
     72:   PetscCall(MatSetFromOptions(M));
     73:   PetscCall(MatGetOwnershipRange(M,&Istart,&Iend));
     74:   for (i=Istart;i<Iend;i++) PetscCall(MatSetValue(M,i,i,mu,INSERT_VALUES));
     75:   PetscCall(MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY));
     76:   PetscCall(MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY));

     78:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     79:                 Create the eigensolver and solve the problem
     80:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     82:   PetscCall(PEPCreate(PETSC_COMM_WORLD,&pep));
     83:   A[0] = K; A[1] = C; A[2] = M;
     84:   PetscCall(PEPSetOperators(pep,3,A));
     85:   PetscCall(PEPSetProblemType(pep,PEP_HYPERBOLIC));
     86:   PetscCall(PEPSetType(pep,PEPSTOAR));

     88:   /*
     89:      Set interval and other settings for spectrum slicing
     90:   */
     91:   int0 = -11.3;
     92:   int1 = -9.5;
     93:   PetscCall(PEPSetInterval(pep,int0,int1));
     94:   PetscCall(PEPSetWhichEigenpairs(pep,PEP_ALL));
     95:   PetscCall(PEPGetST(pep,&st));
     96:   PetscCall(STSetType(st,STSINVERT));
     97:   PetscCall(STGetKSP(st,&ksp));
     98:   PetscCall(KSPSetType(ksp,KSPPREONLY));
     99:   PetscCall(KSPGetPC(ksp,&pc));
    100:   PetscCall(PCSetType(pc,PCCHOLESKY));

    102:   /*
    103:      Test interface functions of STOAR solver
    104:   */
    105:   PetscCall(PEPSTOARGetDetectZeros(pep,&detect));
    106:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Detect zeros before changing = %d",(int)detect));
    107:   PetscCall(PEPSTOARSetDetectZeros(pep,PETSC_TRUE));
    108:   PetscCall(PEPSTOARGetDetectZeros(pep,&detect));
    109:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," ... changed to %d\n",(int)detect));

    111:   PetscCall(PEPSTOARGetLocking(pep,&lock));
    112:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Locking flag before changing = %d",(int)lock));
    113:   PetscCall(PEPSTOARSetLocking(pep,PETSC_TRUE));
    114:   PetscCall(PEPSTOARGetLocking(pep,&lock));
    115:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," ... changed to %d\n",(int)lock));

    117:   PetscCall(PEPSTOARGetCheckEigenvalueType(pep,&checket));
    118:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Check eigenvalue type flag before changing = %d",(int)checket));
    119:   PetscCall(PEPSTOARSetCheckEigenvalueType(pep,PETSC_FALSE));
    120:   PetscCall(PEPSTOARGetCheckEigenvalueType(pep,&checket));
    121:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," ... changed to %d\n",(int)checket));

    123:   PetscCall(PEPSTOARGetDimensions(pep,&nev,&ncv,&mpd));
    124:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Sub-solve dimensions before changing = [%" PetscInt_FMT ",%" PetscInt_FMT ",%" PetscInt_FMT "]",nev,ncv,mpd));
    125:   PetscCall(PEPSTOARSetDimensions(pep,30,60,60));
    126:   PetscCall(PEPSTOARGetDimensions(pep,&nev,&ncv,&mpd));
    127:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," ... changed to [%" PetscInt_FMT ",%" PetscInt_FMT ",%" PetscInt_FMT "]\n",nev,ncv,mpd));

    129:   PetscCall(PEPSetFromOptions(pep));

    131:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    132:              Compute all eigenvalues in interval and display info
    133:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    135:   PetscCall(PEPSetUp(pep));
    136:   PetscCall(PEPSTOARGetInertias(pep,&ns,&shifts,&inertias));
    137:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Inertias (after setup):\n"));
    138:   for (i=0;i<ns;i++) PetscCall(PetscPrintf(PETSC_COMM_WORLD," .. %g (%" PetscInt_FMT ")\n",(double)shifts[i],inertias[i]));
    139:   PetscCall(PetscFree(shifts));
    140:   PetscCall(PetscFree(inertias));

    142:   PetscCall(PEPSolve(pep));
    143:   PetscCall(PEPGetDimensions(pep,&nev,NULL,NULL));
    144:   PetscCall(PEPGetInterval(pep,&int0,&int1));
    145:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Found %" PetscInt_FMT " eigenvalues in interval [%g,%g]\n",nev,(double)int0,(double)int1));

    147:   if (showinertia) {
    148:     PetscCall(PEPSTOARGetInertias(pep,&ns,&shifts,&inertias));
    149:     PetscCall(PetscPrintf(PETSC_COMM_WORLD," Used %" PetscInt_FMT " shifts (inertia):\n",ns));
    150:     for (i=0;i<ns;i++) PetscCall(PetscPrintf(PETSC_COMM_WORLD," .. %g (%" PetscInt_FMT ")\n",(double)shifts[i],inertias[i]));
    151:     PetscCall(PetscFree(shifts));
    152:     PetscCall(PetscFree(inertias));
    153:   }

    155:   PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL));

    157:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    158:                     Clean up
    159:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    160:   PetscCall(PEPDestroy(&pep));
    161:   PetscCall(MatDestroy(&M));
    162:   PetscCall(MatDestroy(&C));
    163:   PetscCall(MatDestroy(&K));
    164:   PetscCall(SlepcFinalize());
    165:   return 0;
    166: }

    168: /*TEST

    170:    test:
    171:       requires: !single
    172:       args: -showinertia 0

    174: TEST*/