Date: 2022-03-31T15:29:16+00:00

Actual source code: ex4.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[] = "Solves a standard eigensystem Ax=kx with the matrix loaded from a file.\n"
     12:   "This example works for both real and complex numbers.\n\n"
     13:   "The command line options are:\n"
     14:   "  -file <filename>, where <filename> = matrix file in PETSc binary form.\n\n";

     16: #include <slepceps.h>

     18: int main(int argc,char **argv)
     19: {
     20:   Mat            A;               /* operator matrix */
     21:   EPS            eps;             /* eigenproblem solver context */
     22:   EPSType        type;
     23:   PetscReal      tol;
     24:   PetscInt       nev,maxit,its;
     25:   char           filename[PETSC_MAX_PATH_LEN];
     26:   PetscViewer    viewer;
     27:   PetscBool      flg,terse;

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

     31:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     32:         Load the operator matrix that defines the eigensystem, Ax=kx
     33:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     35:   PetscPrintf(PETSC_COMM_WORLD,"\nEigenproblem stored in file.\n\n");
     36:   PetscOptionsGetString(NULL,NULL,"-file",filename,sizeof(filename),&flg);

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

     50:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     51:                 Create the eigensolver and set various options
     52:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     54:   /*
     55:      Create eigensolver context
     56:   */
     57:   EPSCreate(PETSC_COMM_WORLD,&eps);

     59:   /*
     60:      Set operators. In this case, it is a standard eigenvalue problem
     61:   */
     62:   EPSSetOperators(eps,A,NULL);

     64:   /*
     65:      Set solver parameters at runtime
     66:   */
     67:   EPSSetFromOptions(eps);

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

     73:   EPSSolve(eps);
     74:   EPSGetIterationNumber(eps,&its);
     75:   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:   EPSGetType(eps,&type);
     81:   PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type);
     82:   EPSGetDimensions(eps,&nev,NULL,NULL);
     83:   PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev);
     84:   EPSGetTolerances(eps,&tol,&maxit);
     85:   PetscPrintf(PETSC_COMM_WORLD," Stopping condition: tol=%.4g, maxit=%" PetscInt_FMT "\n",(double)tol,maxit);

     87:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     88:                     Display solution and clean up
     89:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     91:   /* show detailed info unless -terse option is given by user */
     92:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
     93:   if (terse) EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
     94:   else {
     95:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
     96:     EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD);
     97:     EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
     98:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
     99:   }
    100:   EPSDestroy(&eps);
    101:   MatDestroy(&A);
    102:   SlepcFinalize();
    103:   return 0;
    104: }

    106: /*TEST

    108:    test:
    109:       suffix: 1
    110:       args: -file ${SLEPC_DIR}/share/slepc/datafiles/matrices/rdb200.petsc -eps_nev 4 -terse
    111:       requires: double !complex !defined(PETSC_USE_64BIT_INDICES)

    113:    testset:
    114:       args: -file ${DATAFILESPATH}/matrices/complex/qc324.petsc -eps_type ciss -terse
    115:       requires: double complex datafilespath !defined(PETSC_USE_64BIT_INDICES)
    116:       test:
    117:          suffix: ciss_1
    118:          args: -rg_type ellipse -rg_ellipse_center -.012-.08i -rg_ellipse_radius .05
    119:       test:
    120:          suffix: ciss_2
    121:          args: -rg_type interval -rg_interval_endpoints -0.062,.038,-.13,-.03 -eps_max_it 1

    123: TEST*/