Actual source code: ex4.c

slepc-3.7.0 2016-05-16
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2016, Universitat Politecnica de Valencia, Spain

  6:    This file is part of SLEPc.

  8:    SLEPc is free software: you can redistribute it and/or modify it under  the
  9:    terms of version 3 of the GNU Lesser General Public License as published by
 10:    the Free Software Foundation.

 12:    SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY
 13:    WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS
 14:    FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for
 15:    more details.

 17:    You  should have received a copy of the GNU Lesser General  Public  License
 18:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
 19:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 20: */

 22: static char help[] = "Solves a standard eigensystem Ax=kx with the matrix loaded from a file.\n"
 23:   "This example works for both real and complex numbers.\n\n"
 24:   "The command line options are:\n"
 25:   "  -file <filename>, where <filename> = matrix file in PETSc binary form.\n\n";

 27: #include <slepceps.h>

 31: int main(int argc,char **argv)
 32: {
 33:   Mat            A;               /* operator matrix */
 34:   EPS            eps;             /* eigenproblem solver context */
 35:   EPSType        type;
 36:   PetscReal      tol;
 37:   PetscInt       nev,maxit,its;
 38:   char           filename[PETSC_MAX_PATH_LEN];
 39:   PetscViewer    viewer;
 40:   PetscBool      flg,terse;

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

 45:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 46:         Load the operator matrix that defines the eigensystem, Ax=kx
 47:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 49:   PetscPrintf(PETSC_COMM_WORLD,"\nEigenproblem stored in file.\n\n");
 50:   PetscOptionsGetString(NULL,NULL,"-file",filename,PETSC_MAX_PATH_LEN,&flg);
 51:   if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must indicate a file name with the -file option");

 53: #if defined(PETSC_USE_COMPLEX)
 54:   PetscPrintf(PETSC_COMM_WORLD," Reading COMPLEX matrix from a binary file...\n");
 55: #else
 56:   PetscPrintf(PETSC_COMM_WORLD," Reading REAL matrix from a binary file...\n");
 57: #endif
 58:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
 59:   MatCreate(PETSC_COMM_WORLD,&A);
 60:   MatSetFromOptions(A);
 61:   MatLoad(A,viewer);
 62:   PetscViewerDestroy(&viewer);

 64:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 65:                 Create the eigensolver and set various options
 66:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 68:   /*
 69:      Create eigensolver context
 70:   */
 71:   EPSCreate(PETSC_COMM_WORLD,&eps);

 73:   /*
 74:      Set operators. In this case, it is a standard eigenvalue problem
 75:   */
 76:   EPSSetOperators(eps,A,NULL);

 78:   /*
 79:      Set solver parameters at runtime
 80:   */
 81:   EPSSetFromOptions(eps);

 83:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 84:                       Solve the eigensystem
 85:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 87:   EPSSolve(eps);
 88:   EPSGetIterationNumber(eps,&its);
 89:   PetscPrintf(PETSC_COMM_WORLD," Number of iterations of the method: %D\n",its);

 91:   /*
 92:      Optional: Get some information from the solver and display it
 93:   */
 94:   EPSGetType(eps,&type);
 95:   PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type);
 96:   EPSGetDimensions(eps,&nev,NULL,NULL);
 97:   PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %D\n",nev);
 98:   EPSGetTolerances(eps,&tol,&maxit);
 99:   PetscPrintf(PETSC_COMM_WORLD," Stopping condition: tol=%.4g, maxit=%D\n",(double)tol,maxit);

101:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
102:                     Display solution and clean up
103:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

105:   /* show detailed info unless -terse option is given by user */
106:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
107:   if (terse) {
108:     EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
109:   } else {
110:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
111:     EPSReasonView(eps,PETSC_VIEWER_STDOUT_WORLD);
112:     EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
113:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
114:   }
115:   EPSDestroy(&eps);
116:   MatDestroy(&A);
117:   SlepcFinalize();
118:   return ierr;
119: }