Date: 2026-03-09T09:12:01+00:00

Actual source code: ex17.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[] = "Solves a polynomial eigenproblem P(l)x = 0 with matrices loaded from a file.\n\n"
     12:   "The command line options are:\n"
     13:   "-A <filename1,filename2, ...> , where <filename1,.. > = matrices A0 ... files in PETSc binary form.\n\n";

     15: #include <slepcpep.h>

     17: #define MAX_MATRICES 40

     19: int main(int argc,char **argv)
     20: {
     21:   Mat            A[MAX_MATRICES]; /* problem matrices */
     22:   PEP            pep;             /* polynomial eigenproblem solver context */
     23:   PetscReal      tol;
     24:   PetscInt       nev,maxit,its,nmat=MAX_MATRICES,i;
     25:   char*          filenames[MAX_MATRICES];
     26:   PetscViewer    viewer;
     27:   PetscBool      flg,terse;

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

     32:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     33:         Load the matrices that define the polynomial eigenproblem
     34:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     36:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nPolynomial eigenproblem stored in file.\n\n"));
     37: #if defined(PETSC_USE_COMPLEX)
     38:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Reading COMPLEX matrices from binary files...\n"));
     39: #else
     40:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Reading REAL matrices from binary files...\n"));
     41: #endif
     42:   PetscCall(PetscOptionsGetStringArray(NULL,NULL,"-A",filenames,&nmat,&flg));
     43:   PetscCheck(flg,PETSC_COMM_WORLD,PETSC_ERR_USER_INPUT,"Must indicate a comma-separated list of file names with the -A option");
     44:   for (i=0;i<nmat;i++) {
     45:     PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD,filenames[i],FILE_MODE_READ,&viewer));
     46:     PetscCall(MatCreate(PETSC_COMM_WORLD,&A[i]));
     47:     PetscCall(MatSetFromOptions(A[i]));
     48:     PetscCall(MatLoad(A[i],viewer));
     49:     PetscCall(PetscViewerDestroy(&viewer));
     50:   }
     51:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     52:                 Create the eigensolver and set various options
     53:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     55:   /*
     56:      Create eigensolver context
     57:   */
     58:   PetscCall(PEPCreate(PETSC_COMM_WORLD,&pep));

     60:   /*
     61:      Set matrices
     62:   */
     63:   PetscCall(PEPSetOperators(pep,nmat,A));
     64:   /*
     65:      Set solver parameters at runtime
     66:   */
     67:   PetscCall(PEPSetFromOptions(pep));

     69:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     70:                       Solve the eigensystem
     71:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     73:   PetscCall(PEPSolve(pep));
     74:   PetscCall(PEPGetIterationNumber(pep,&its));
     75:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Number of iterations of the method: %" PetscInt_FMT "\n",its));

     77:   /*
     78:      Optional: Get some information from the solver and display it
     79:   */
     80:   PetscCall(PEPGetDimensions(pep,&nev,NULL,NULL));
     81:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev));
     82:   PetscCall(PEPGetTolerances(pep,&tol,&maxit));
     83:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Stopping condition: tol=%.4g, maxit=%" PetscInt_FMT "\n",(double)tol,maxit));

     85:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     86:                     Display solution and clean up
     87:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     89:   /* show detailed info unless -terse option is given by user */
     90:   PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
     91:   if (terse) PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL));
     92:   else {
     93:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
     94:     PetscCall(PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD));
     95:     PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD));
     96:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
     97:   }
     98:   PetscCall(PEPDestroy(&pep));
     99:   for (i=0;i<nmat;i++) {
    100:     PetscCall(MatDestroy(&A[i]));
    101:     PetscCall(PetscFree(filenames[i]));
    102:   }
    103:   PetscCall(SlepcFinalize());
    104:   return 0;
    105: }

    107: /*TEST

    109:    test:
    110:       suffix: 1
    111:       args: -A ${SLEPC_DIR}/share/slepc/datafiles/matrices/speaker107k.petsc,${SLEPC_DIR}/share/slepc/datafiles/matrices/speaker107c.petsc,${SLEPC_DIR}/share/slepc/datafiles/matrices/speaker107m.petsc -pep_type {{toar qarnoldi linear}} -pep_nev 4 -pep_ncv 20 -pep_scale scalar -terse
    112:       requires: double !complex !defined(PETSC_USE_64BIT_INDICES)

    114: TEST*/