Date: 2022-08-09T09:05:50+00:00

Actual source code: test8.c
slepc-3.17.2 2022-08-09
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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: static char help[] = "Test interface functions of polynomial JD.\n\n"
     12:   "This is based on ex16.c. The command line options are:\n"
     13:   "  -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
     14:   "  -m <m>, where <m> = number of grid subdivisions in y dimension.\n\n";

     16: #include <slepcpep.h>

     18: int main(int argc,char **argv)
     19: {
     20:   Mat             M,C,K,A[3];      /* problem matrices */
     21:   PEP             pep;             /* polynomial eigenproblem solver context */
     22:   PetscInt        N,n=10,m,Istart,Iend,II,i,j,midx;
     23:   PetscReal       restart,fix;
     24:   PetscBool       flag,reuse;
     25:   PEPJDProjection proj;

     27:   SlepcInitialize(&argc,&argv,(char*)0,help);

     29:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
     30:   PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag);
     31:   if (!flag) m=n;
     32:   N = n*m;
     33:   PetscPrintf(PETSC_COMM_WORLD,"\nQuadratic Eigenproblem, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m);

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

     39:   /* K is the 2-D Laplacian */
     40:   MatCreate(PETSC_COMM_WORLD,&K);
     41:   MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,N,N);
     42:   MatSetFromOptions(K);
     43:   MatSetUp(K);
     44:   MatGetOwnershipRange(K,&Istart,&Iend);
     45:   for (II=Istart;II<Iend;II++) {
     46:     i = II/n; j = II-i*n;
     47:     if (i>0) MatSetValue(K,II,II-n,-1.0,INSERT_VALUES);
     48:     if (i<m-1) MatSetValue(K,II,II+n,-1.0,INSERT_VALUES);
     49:     if (j>0) MatSetValue(K,II,II-1,-1.0,INSERT_VALUES);
     50:     if (j<n-1) MatSetValue(K,II,II+1,-1.0,INSERT_VALUES);
     51:     MatSetValue(K,II,II,4.0,INSERT_VALUES);
     52:   }
     53:   MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
     54:   MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);

     56:   /* C is the 1-D Laplacian on horizontal lines */
     57:   MatCreate(PETSC_COMM_WORLD,&C);
     58:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,N,N);
     59:   MatSetFromOptions(C);
     60:   MatSetUp(C);
     61:   MatGetOwnershipRange(C,&Istart,&Iend);
     62:   for (II=Istart;II<Iend;II++) {
     63:     i = II/n; j = II-i*n;
     64:     if (j>0) MatSetValue(C,II,II-1,-1.0,INSERT_VALUES);
     65:     if (j<n-1) MatSetValue(C,II,II+1,-1.0,INSERT_VALUES);
     66:     MatSetValue(C,II,II,2.0,INSERT_VALUES);
     67:   }
     68:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
     69:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

     71:   /* M is a diagonal matrix */
     72:   MatCreate(PETSC_COMM_WORLD,&M);
     73:   MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,N,N);
     74:   MatSetFromOptions(M);
     75:   MatSetUp(M);
     76:   MatGetOwnershipRange(M,&Istart,&Iend);
     77:   for (II=Istart;II<Iend;II++) MatSetValue(M,II,II,(PetscReal)(II+1),INSERT_VALUES);
     78:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
     79:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);

     81:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     82:                 Create the eigensolver and set various options
     83:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     85:   PEPCreate(PETSC_COMM_WORLD,&pep);
     86:   A[0] = K; A[1] = C; A[2] = M;
     87:   PEPSetOperators(pep,3,A);
     88:   PEPSetType(pep,PEPJD);

     90:   /*
     91:      Test interface functions of JD solver
     92:   */
     93:   PEPJDGetRestart(pep,&restart);
     94:   PetscPrintf(PETSC_COMM_WORLD," Restart parameter before changing = %g",(double)restart);
     95:   PEPJDSetRestart(pep,0.3);
     96:   PEPJDGetRestart(pep,&restart);
     97:   PetscPrintf(PETSC_COMM_WORLD," ... changed to %g\n",(double)restart);

     99:   PEPJDGetFix(pep,&fix);
    100:   PetscPrintf(PETSC_COMM_WORLD," Fix parameter before changing = %g",(double)fix);
    101:   PEPJDSetFix(pep,0.001);
    102:   PEPJDGetFix(pep,&fix);
    103:   PetscPrintf(PETSC_COMM_WORLD," ... changed to %g\n",(double)fix);

    105:   PEPJDGetReusePreconditioner(pep,&reuse);
    106:   PetscPrintf(PETSC_COMM_WORLD," Reuse preconditioner flag before changing = %d",(int)reuse);
    107:   PEPJDSetReusePreconditioner(pep,PETSC_TRUE);
    108:   PEPJDGetReusePreconditioner(pep,&reuse);
    109:   PetscPrintf(PETSC_COMM_WORLD," ... changed to %d\n",(int)reuse);

    111:   PEPJDGetProjection(pep,&proj);
    112:   PetscPrintf(PETSC_COMM_WORLD," Projection type before changing = %d",(int)proj);
    113:   PEPJDSetProjection(pep,PEP_JD_PROJECTION_ORTHOGONAL);
    114:   PEPJDGetProjection(pep,&proj);
    115:   PetscPrintf(PETSC_COMM_WORLD," ... changed to %d\n",(int)proj);

    117:   PEPJDGetMinimalityIndex(pep,&midx);
    118:   PetscPrintf(PETSC_COMM_WORLD," Minimality index before changing = %" PetscInt_FMT,midx);
    119:   PEPJDSetMinimalityIndex(pep,2);
    120:   PEPJDGetMinimalityIndex(pep,&midx);
    121:   PetscPrintf(PETSC_COMM_WORLD," ... changed to %" PetscInt_FMT "\n",midx);

    123:   PEPSetFromOptions(pep);

    125:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    126:                       Solve the eigensystem
    127:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    129:   PEPSolve(pep);
    130:   PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
    131:   PEPDestroy(&pep);
    132:   MatDestroy(&M);
    133:   MatDestroy(&C);
    134:   MatDestroy(&K);
    135:   SlepcFinalize();
    136:   return 0;
    137: }

    139: /*TEST

    141:    test:
    142:       args: -n 12 -pep_nev 2 -pep_ncv 21 -pep_conv_abs

    144: TEST*/