Date: 2016-09-29T11:12:05+00:00

Actual source code: svddefault.c
slepc-3.7.3 2016-09-29
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      1: /*
      2:      This file contains some simple default routines for common operations.

      4:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      5:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      6:    Copyright (c) 2002-2016, Universitat Politecnica de Valencia, Spain

      8:    This file is part of SLEPc.

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

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

     19:    You  should have received a copy of the GNU Lesser General  Public  License
     20:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
     21:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     22: */

     24: #include <slepc/private/svdimpl.h>      /*I "slepcsvd.h" I*/

     28: /*
     29:   SVDConvergedRelative - Checks convergence relative to the eigenvalue.
     30: */
     31: PetscErrorCode SVDConvergedRelative(SVD svd,PetscReal sigma,PetscReal res,PetscReal *errest,void *ctx)
     32: {
     34:   *errest = res/sigma;
     35:   return(0);
     36: }

     40: /*
     41:   SVDConvergedAbsolute - Checks convergence absolutely.
     42: */
     43: PetscErrorCode SVDConvergedAbsolute(SVD svd,PetscReal sigma,PetscReal res,PetscReal *errest,void *ctx)
     44: {
     46:   *errest = res;
     47:   return(0);
     48: }

     52: /*@C
     53:    SVDStoppingBasic - Default routine to determine whether the outer singular value
     54:    solver iteration must be stopped.

     56:    Collective on SVD

     58:    Input Parameters:
     59: +  svd    - singular value solver context obtained from SVDCreate()
     60: .  its    - current number of iterations
     61: .  max_it - maximum number of iterations
     62: .  nconv  - number of currently converged singular triplets
     63: .  nsv    - number of requested singular triplets
     64: -  ctx    - context (not used here)

     66:    Output Parameter:
     67: .  reason - result of the stopping test

     69:    Notes:
     70:    A positive value of reason indicates that the iteration has finished successfully
     71:    (converged), and a negative value indicates an error condition (diverged). If
     72:    the iteration needs to be continued, reason must be set to SVD_CONVERGED_ITERATING
     73:    (zero).

     75:    SVDStoppingBasic() will stop if all requested singular values are converged, or if
     76:    the maximum number of iterations has been reached.

     78:    Use SVDSetStoppingTest() to provide your own test instead of using this one.

     80:    Level: advanced

     82: .seealso: SVDSetStoppingTest(), SVDConvergedReason, SVDGetConvergedReason()
     83: @*/
     84: PetscErrorCode SVDStoppingBasic(SVD svd,PetscInt its,PetscInt max_it,PetscInt nconv,PetscInt nsv,SVDConvergedReason *reason,void *ctx)
     85: {

     89:   *reason = SVD_CONVERGED_ITERATING;
     90:   if (nconv >= nsv) {
     91:     PetscInfo2(svd,"Singular value solver finished successfully: %D singular triplets converged at iteration %D\n",nconv,its);
     92:     *reason = SVD_CONVERGED_TOL;
     93:   } else if (its >= max_it) {
     94:     *reason = SVD_DIVERGED_ITS;
     95:     PetscInfo1(svd,"Singular value solver iteration reached maximum number of iterations (%D)\n",its);
     96:   }
     97:   return(0);
     98: }