Actual source code: mfnsolve.c

  1: /*
  2:       MFN routines related to the solution process.

  4:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  5:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  6:    Copyright (c) 2002-2013, 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/mfnimpl.h>   /*I "slepcmfn.h" I*/

 28: /*@
 29:    MFNSolve - Solves the matrix function problem. Given a vector b, the
 30:    vector x = f(alpha*A)*b is returned.

 32:    Collective on MFN

 34:    Input Parameters:
 35: +  mfn - matrix function context obtained from MFNCreate()
 36: -  b   - the right hand side vector

 38:    Output Parameter:
 39: .  x   - the solution

 41:    Options Database Keys:
 42: +  -mfn_view - print information about the solver used
 43: .  -mfn_view_mat binary - save the matrix to the default binary viewer
 44: .  -mfn_view_rhs binary - save right hand side vector to the default binary viewer
 45: -  -mfn_view_solution binary - save computed solution vector to the default binary viewer

 47:    Notes:
 48:    The matrix A is specified with MFNSetOperator().
 49:    The function f is specified with MFNSetFunction().
 50:    The scalar alpha is specified with MFNSetScaleFactor().

 52:    Level: beginner

 54: .seealso: MFNCreate(), MFNSetUp(), MFNDestroy(), MFNSetTolerances(),
 55:           MFNSetOperator(), MFNSetFunction(), MFNSetScaleFactor()
 56: @*/
 57: PetscErrorCode MFNSolve(MFN mfn,Vec b,Vec x)
 58: {
 59:   PetscErrorCode    ierr;
 60:   PetscBool         flg;
 61:   PetscViewer       viewer;
 62:   PetscViewerFormat format;


 71:   /* call setup */
 72:   MFNSetUp(mfn);
 73:   mfn->its = 0;

 75:   MFNMonitor(mfn,mfn->its,0);

 77:   /* call solver */
 78:   PetscLogEventBegin(MFN_Solve,mfn,b,x,0);
 79:   (*mfn->ops->solve)(mfn,b,x);
 80:   PetscLogEventEnd(MFN_Solve,mfn,b,x,0);

 82:   if (!mfn->reason) SETERRQ(PetscObjectComm((PetscObject)mfn),PETSC_ERR_PLIB,"Internal error, solver returned without setting converged reason");

 84:   if (mfn->errorifnotconverged && mfn->reason < 0) SETERRQ(PetscObjectComm((PetscObject)mfn),PETSC_ERR_NOT_CONVERGED,"MFNSolve has not converged");

 86:   /* various viewers */
 87:   MatViewFromOptions(mfn->A,((PetscObject)mfn)->prefix,"-mfn_view_mat");
 88:   VecViewFromOptions(b,((PetscObject)mfn)->prefix,"-mfn_view_rhs");
 89:   VecViewFromOptions(x,((PetscObject)mfn)->prefix,"-mfn_view_solution");

 91:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)mfn),((PetscObject)mfn)->prefix,"-mfn_view",&viewer,&format,&flg);
 92:   if (flg && !PetscPreLoadingOn) {
 93:     PetscViewerPushFormat(viewer,format);
 94:     MFNView(mfn,viewer);
 95:     PetscViewerPopFormat(viewer);
 96:     PetscViewerDestroy(&viewer);
 97:   }
 98:   return(0);
 99: }

103: /*@
104:    MFNGetIterationNumber - Gets the current iteration number. If the
105:    call to MFNSolve() is complete, then it returns the number of iterations
106:    carried out by the solution method.

108:    Not Collective

110:    Input Parameter:
111: .  mfn - the matrix function context

113:    Output Parameter:
114: .  its - number of iterations

116:    Level: intermediate

118:    Note:
119:    During the i-th iteration this call returns i-1. If MFNSolve() is
120:    complete, then parameter "its" contains either the iteration number at
121:    which convergence was successfully reached, or failure was detected.
122:    Call MFNGetConvergedReason() to determine if the solver converged or
123:    failed and why.

125: .seealso: MFNGetConvergedReason(), MFNSetTolerances()
126: @*/
127: PetscErrorCode MFNGetIterationNumber(MFN mfn,PetscInt *its)
128: {
132:   *its = mfn->its;
133:   return(0);
134: }

138: /*@C
139:    MFNGetConvergedReason - Gets the reason why the MFNSolve() iteration was
140:    stopped.

142:    Not Collective

144:    Input Parameter:
145: .  mfn - the matrix function context

147:    Output Parameter:
148: .  reason - negative value indicates diverged, positive value converged

150:    Possible values for reason:
151: +  MFN_CONVERGED_TOL - converged up to tolerance
152: .  MFN_DIVERGED_ITS - required more than its to reach convergence
153: -  MFN_DIVERGED_BREAKDOWN - generic breakdown in method

155:    Note:
156:    Can only be called after the call to MFNSolve() is complete.

158:    Level: intermediate

160: .seealso: MFNSetTolerances(), MFNSolve(), MFNConvergedReason, MFNSetErrorIfNotConverged()
161: @*/
162: PetscErrorCode MFNGetConvergedReason(MFN mfn,MFNConvergedReason *reason)
163: {
167:   *reason = mfn->reason;
168:   return(0);
169: }