Date: 2022-03-31T15:29:17+00:00

Actual source code: ex43.c
slepc-3.17.0 2022-03-31
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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[] = "Generalized eigenproblem, illustrates setting MUMPS options.\n\n"
     12:   "The problem is Ax = lambda Bx, with:\n"
     13:   "   A = Laplacian operator in 2-D\n"
     14:   "   B = diagonal matrix with all values equal to 4\n\n"
     15:   "The command line options are:\n"
     16:   "  -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
     17:   "  -m <m>, where <m> = number of grid subdivisions in y dimension.\n\n";

     19: #include <slepceps.h>

     21: int main(int argc,char **argv)
     22: {
     23:   Mat            A,B;
     24: #if defined(PETSC_HAVE_MUMPS)
     25:   Mat            K;
     26: #endif
     27:   EPS            eps;
     28:   EPSType        type;
     29:   ST             st;
     30:   KSP            ksp;
     31:   PC             pc;
     32:   PetscInt       N,n=10,m=12,Istart,Iend,II,nev,i,j;
     33:   PetscBool      flag,terse;

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

     37:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
     38:   PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag);
     39:   N = n*m;
     40:   PetscPrintf(PETSC_COMM_WORLD,"\nGeneralized Eigenproblem, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m);

     42:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     43:      Compute the matrices that define the eigensystem, Ax=kBx
     44:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     46:   MatCreate(PETSC_COMM_WORLD,&A);
     47:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N);
     48:   MatSetFromOptions(A);
     49:   MatSetUp(A);

     51:   MatCreate(PETSC_COMM_WORLD,&B);
     52:   MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,N,N);
     53:   MatSetFromOptions(B);
     54:   MatSetUp(B);

     56:   MatGetOwnershipRange(A,&Istart,&Iend);
     57:   for (II=Istart;II<Iend;II++) {
     58:     i = II/n; j = II-i*n;
     59:     if (i>0) MatSetValue(A,II,II-n,-1.0,INSERT_VALUES);
     60:     if (i<m-1) MatSetValue(A,II,II+n,-1.0,INSERT_VALUES);
     61:     if (j>0) MatSetValue(A,II,II-1,-1.0,INSERT_VALUES);
     62:     if (j<n-1) MatSetValue(A,II,II+1,-1.0,INSERT_VALUES);
     63:     MatSetValue(A,II,II,4.0,INSERT_VALUES);
     64:     MatSetValue(B,II,II,4.0,INSERT_VALUES);
     65:   }

     67:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
     68:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
     69:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
     70:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);

     72:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     73:                 Create the eigensolver and set various options
     74:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     76:   /*
     77:      Create eigensolver context
     78:   */
     79:   EPSCreate(PETSC_COMM_WORLD,&eps);

     81:   /*
     82:      Set operators. In this case, it is a generalized eigenvalue problem
     83:   */
     84:   EPSSetOperators(eps,A,B);
     85:   EPSSetProblemType(eps,EPS_GNHEP);

     87:   /*
     88:      Set some solver options
     89:   */
     90:   EPSSetTarget(eps,1.3);
     91:   EPSSetDimensions(eps,2,PETSC_DEFAULT,PETSC_DEFAULT);
     92:   EPSGetST(eps,&st);
     93:   STSetType(st,STSINVERT);

     95:   STGetKSP(st,&ksp);
     96:   KSPSetType(ksp,KSPPREONLY);
     97:   KSPGetPC(ksp,&pc);
     98:   PCSetType(pc,PCLU);

    100:   /*
    101:      Set MUMPS options if available
    102:   */
    103: #if defined(PETSC_HAVE_MUMPS)
    104:   PCFactorSetMatSolverType(pc,MATSOLVERMUMPS);
    105:   /* the next line is required to force the creation of the ST operator and its passing to KSP */
    106:   STGetOperator(st,NULL);
    107:   PCFactorSetUpMatSolverType(pc);
    108:   PCFactorGetMatrix(pc,&K);
    109:   MatMumpsSetIcntl(K,14,50);
    110:   MatMumpsSetCntl(K,3,1e-12);
    111: #endif

    113:   /*
    114:      Let the user change settings at runtime
    115:   */
    116:   EPSSetFromOptions(eps);

    118:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    119:                       Solve the eigensystem
    120:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    122:   EPSSolve(eps);

    124:   /*
    125:      Optional: Get some information from the solver and display it
    126:   */
    127:   EPSGetType(eps,&type);
    128:   PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type);
    129:   EPSGetDimensions(eps,&nev,NULL,NULL);
    130:   PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev);

    132:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    133:                     Display solution and clean up
    134:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    136:   /* show detailed info unless -terse option is given by user */
    137:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
    138:   if (terse) EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
    139:   else {
    140:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
    141:     EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD);
    142:     EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
    143:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
    144:   }
    145:   EPSDestroy(&eps);
    146:   MatDestroy(&A);
    147:   MatDestroy(&B);
    148:   SlepcFinalize();
    149:   return 0;
    150: }

    152: /*TEST

    154:    testset:
    155:       args: -terse
    156:       output_file: output/ex43_1.out
    157:       test:
    158:          suffix: 1
    159:       test:
    160:          suffix: 2
    161:          nsize: 2
    162:          args: -st_pc_factor_mat_solver_type mumps
    163:          requires: mumps

    165: TEST*/