Actual source code: test16.c

slepc-3.5.2 2014-10-10
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2014, 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[] = "Tests a user-defined convergence test.\n\n";

 24: #include <slepceps.h>


 29: /*
 30:   MyConvergedAbsolute - Bizarre convergence test that requires more accuracy
 31:   to positive eigenvalues compared to negative ones.
 32: */
 33: PetscErrorCode MyConvergedAbsolute(EPS eps,PetscScalar eigr,PetscScalar eigi,PetscReal res,PetscReal *errest,void *ctx)
 34: {
 36:   *errest = (PetscRealPart(eigr)<0.0)?res:100*res;
 37:   return(0);
 38: }

 42: int main(int argc,char **argv)
 43: {
 44:   Mat            A;           /* problem matrix */
 45:   EPS            eps;         /* eigenproblem solver context */
 46:   PetscScalar    value[2];
 47:   PetscInt       n=30,i,Istart,Iend,col[2];
 48:   PetscBool      FirstBlock=PETSC_FALSE,LastBlock=PETSC_FALSE;

 51:   SlepcInitialize(&argc,&argv,(char*)0,help);
 52:   PetscOptionsGetInt(NULL,"-n",&n,NULL);
 53:   PetscPrintf(PETSC_COMM_WORLD,"\nTridiagonal Eigenproblem, n=%D\n\n",n);

 55:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 56:      Compute the operator matrix that defines the eigensystem, Ax=kx
 57:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 59:   MatCreate(PETSC_COMM_WORLD,&A);
 60:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
 61:   MatSetFromOptions(A);
 62:   MatSetUp(A);

 64:   MatGetOwnershipRange(A,&Istart,&Iend);
 65:   if (Istart==0) FirstBlock=PETSC_TRUE;
 66:   if (Iend==n) LastBlock=PETSC_TRUE;
 67:   value[0]=-1.0; value[1]=-1.0;
 68:   for (i=(FirstBlock? Istart+1: Istart); i<(LastBlock? Iend-1: Iend); i++) {
 69:     col[0]=i-1; col[1]=i+1;
 70:     MatSetValues(A,1,&i,2,col,value,INSERT_VALUES);
 71:   }
 72:   if (LastBlock) {
 73:     i=n-1; col[0]=n-2;
 74:     MatSetValues(A,1,&i,1,col,value,INSERT_VALUES);
 75:   }
 76:   if (FirstBlock) {
 77:     i=0; col[0]=1;
 78:     MatSetValues(A,1,&i,1,col,value,INSERT_VALUES);
 79:   }

 81:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 82:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

 84:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 85:                         Create the eigensolver
 86:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 87:   EPSCreate(PETSC_COMM_WORLD,&eps);
 88:   EPSSetOperators(eps,A,NULL);
 89:   EPSSetProblemType(eps,EPS_HEP);
 90:   /* set user-defined convergence test */
 91:   EPSSetConvergenceTestFunction(eps,MyConvergedAbsolute,NULL,NULL);
 92:   EPSSetFromOptions(eps);

 94:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 95:                           Solve the problem
 96:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 97:   EPSSolve(eps);
 98:   EPSPrintSolution(eps,NULL);

100:   EPSDestroy(&eps);
101:   MatDestroy(&A);
102:   SlepcFinalize();
103:   return 0;
104: }