Date: 2026-03-31T13:23:28+00:00

Actual source code: test26.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[] = "Illustrates the PGNHEP problem type.\n\n"
     12:   "Based on ex7.\n"
     13:   "The command line options are:\n"
     14:   "  -f1 <filename> -f2 <filename>, PETSc binary files containing A and B.\n\n";

     16: #include <slepceps.h>

     18: int main(int argc,char **argv)
     19: {
     20:   EPS               eps;
     21:   Mat               A,B;
     22:   PetscBool         flg;
     23:   PetscReal         tol=1000*PETSC_MACHINE_EPSILON;
     24:   char              filename[PETSC_MAX_PATH_LEN];
     25:   PetscViewer       viewer;

     27:   PetscFunctionBeginUser;
     28:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));
     29:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nPGNHEP problem loaded from file\n\n"));

     31:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     32:         Load the matrices that define the eigensystem, Ax=kBx
     33:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     35:   PetscCall(PetscOptionsGetString(NULL,NULL,"-f1",filename,sizeof(filename),&flg));
     36:   PetscCheck(flg,PETSC_COMM_WORLD,PETSC_ERR_USER_INPUT,"Must indicate a file name for matrix A with the -f1 option");

     38: #if defined(PETSC_USE_COMPLEX)
     39:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Reading COMPLEX matrices from binary files...\n"));
     40: #else
     41:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Reading REAL matrices from binary files...\n"));
     42: #endif
     43:   PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer));
     44:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
     45:   PetscCall(MatSetFromOptions(A));
     46:   PetscCall(MatLoad(A,viewer));
     47:   PetscCall(PetscViewerDestroy(&viewer));

     49:   PetscCall(PetscOptionsGetString(NULL,NULL,"-f2",filename,sizeof(filename),&flg));
     50:   if (flg) {
     51:     PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer));
     52:     PetscCall(MatCreate(PETSC_COMM_WORLD,&B));
     53:     PetscCall(MatSetFromOptions(B));
     54:     PetscCall(MatLoad(B,viewer));
     55:     PetscCall(PetscViewerDestroy(&viewer));
     56:   } else {
     57:     PetscCall(PetscPrintf(PETSC_COMM_WORLD," Matrix B was not provided, setting B=I\n\n"));
     58:     B = NULL;
     59:   }

     61:   /* This example is intended for a matrix pair (A,B) where B is symmetric positive definite;
     62:      If we load matrices bfw62a/bfw62b, scale both of them because bfw62b is negative definite */
     63:   PetscCall(PetscStrendswith(filename,"bfw62b.petsc",&flg));
     64:   if (flg) {
     65:     PetscCall(MatScale(A,-1.0));
     66:     PetscCall(MatScale(B,-1.0));
     67:   }

     69:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     70:                 Create the eigensolver and solve the problem
     71:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     73:   PetscCall(EPSCreate(PETSC_COMM_WORLD,&eps));
     74:   PetscCall(EPSSetOperators(eps,A,B));
     75:   PetscCall(EPSSetProblemType(eps,EPS_PGNHEP));
     76:   PetscCall(EPSSetTolerances(eps,tol,PETSC_CURRENT));
     77:   PetscCall(EPSSetFromOptions(eps));
     78:   PetscCall(EPSSolve(eps));

     80:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     81:                     Display solution and clean up
     82:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     84:   PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
     85:   PetscCall(EPSDestroy(&eps));
     86:   PetscCall(MatDestroy(&A));
     87:   PetscCall(MatDestroy(&B));
     88:   PetscCall(SlepcFinalize());
     89:   return 0;
     90: }

     92: /*TEST

     94:    testset:
     95:       args: -f1 ${SLEPC_DIR}/share/slepc/datafiles/matrices/bfw62a.petsc -f2 ${SLEPC_DIR}/share/slepc/datafiles/matrices/bfw62b.petsc -eps_largest_real -eps_nev 4
     96:       requires: double !complex !defined(PETSC_USE_64BIT_INDICES)
     97:       output_file: output/test26_1.out
     98:       test:
     99:          args: -eps_true_residual {{0 1}} -eps_two_sided {{0 1}} -eps_ncv 32
    100:          suffix: 1
    101:       test:
    102:          args: -eps_type arpack
    103:          suffix: 1_arpack
    104:          requires: arpack

    106:    testset:
    107:       args: -f1 ${DATAFILESPATH}/matrices/complex/mhd1280a.petsc -f2 ${DATAFILESPATH}/matrices/complex/mhd1280b.petsc -eps_smallest_real -eps_nev 4
    108:       requires: double complex datafilespath !defined(PETSC_USE_64BIT_INDICES)
    109:       output_file: output/test26_2.out
    110:       test:
    111:          args: -eps_two_sided {{0 1}}
    112:          suffix: 2
    113:       test:
    114:          args: -eps_type arpack
    115:          suffix: 2_arpack
    116:          requires: arpack

    118: TEST*/