Belos Package Browser (Single Doxygen Collection) Development
BelosOpAkx.hpp
Go to the documentation of this file.
00001 //@HEADER
00002 // ************************************************************************
00003 //
00004 //                 Belos: Block Linear Solvers Package
00005 //                  Copyright 2004 Sandia Corporation
00006 //
00007 // Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
00008 // the U.S. Government retains certain rights in this software.
00009 //
00010 // Redistribution and use in source and binary forms, with or without
00011 // modification, are permitted provided that the following conditions are
00012 // met:
00013 //
00014 // 1. Redistributions of source code must retain the above copyright
00015 // notice, this list of conditions and the following disclaimer.
00016 //
00017 // 2. Redistributions in binary form must reproduce the above copyright
00018 // notice, this list of conditions and the following disclaimer in the
00019 // documentation and/or other materials provided with the distribution.
00020 //
00021 // 3. Neither the name of the Corporation nor the names of the
00022 // contributors may be used to endorse or promote products derived from
00023 // this software without specific prior written permission.
00024 //
00025 // THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
00026 // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00027 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
00028 // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SANDIA CORPORATION OR THE
00029 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00030 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
00031 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00032 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00033 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00034 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00035 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00036 //
00037 // Questions? Contact Michael A. Heroux (maherou@sandia.gov)
00038 //
00039 // ************************************************************************
00040 //@HEADER
00041 
00042 #ifndef __Belos_OpAkx_hpp
00043 #define __Belos_OpAkx_hpp
00044 
00045 #include <BelosAkx.hpp>
00046 #include <BelosOperatorTraits.hpp>
00047 #include <Teuchos_OrdinalTraits.hpp>
00048 #include <Teuchos_SerialDenseVector.hpp>
00049 
00050 namespace Belos {
00051 
00070   template<class Scalar, class MV, class OP>
00071   class OpAkx : public Akx<Scalar, MV> {
00072   public:
00086     OpAkx (const Teuchos::RCP<const OP>& A, 
00087      const Teuchos::RCP<const OP>& M_left, 
00088      const Teuchos::RCP<const OP>& M_right,
00089      const int recommendedBasisLength) :
00090       A_ (A), 
00091       M_left_ (M_left), 
00092       M_right_ (M_right),
00093       recommendedBasisLength_ (validatedBasisLength (recommendedBasisLength))
00094     {}
00095   
00097     int maxCandidateBasisLength () const { 
00098       // We're not using a special matrix powers kernel implementation
00099       // here, just whatever operator(s) we were given, so we can
00100       // apply them as many times as we want.  Of course, this doesn't
00101       // account for memory or time constraints.
00102       return Teuchos::OrdinalTraits<int>::max(); 
00103     }
00104 
00106     int recommendedCandidateBasisLength () const {
00107       return recommendedBasisLength_;
00108     }
00109 
00110   protected:
00126     void 
00127     applyOp (const MV& v_prv, MV& v_cur) 
00128     {
00129       // We use v_scratch_ as scratch space, since
00130       // OperatorTraits::Apply() doesn't allow aliasing of the input
00131       // and output vectors when applying an operator.  We only
00132       // allocate v_scratch_ if necessary.
00133       if (! M_right_.is_null())
00134   {
00135     if (v_scratch_.is_null())
00136       v_scratch_ = MVT::Clone (v_cur);
00137     OPT::Apply (*M_right_, v_prv, *v_scratch_);
00138     OPT::Apply (*A_, *v_scratch_, v_cur);
00139     if (! M_left_.is_null())
00140       {
00141         MVT::Assign (v_cur, *v_scratch_);
00142         OPT::Apply (*M_left_, *v_scratch_, v_cur);
00143       }
00144   }
00145       else if (! M_left_.is_null())
00146   {
00147     if (v_scratch_.is_null())
00148       v_scratch_ = MVT::Clone (v_cur);
00149     OPT::Apply (*A_, v_prv, *v_scratch_);
00150     OPT::Apply (*M_left_, *v_scratch_, v_cur);
00151   }
00152       else
00153   OPT::Apply (*A_, v_prv, v_cur);
00154     }
00155 
00174     void
00175     applyFlexibleOp (const MV& v_prv, MV& z_cur, MV& v_cur)
00176     {
00177       TEUCHOS_TEST_FOR_EXCEPTION(! M_left_.is_null(), std::logic_error,
00178        "Flexible GMRES only works with a right "
00179        "preconditioner, not a left or split "
00180        "preconditioner.");
00181       if (! M_right_.is_null())
00182   { 
00183     OPT::Apply (*M_right_, v_prv, z_cur);
00184     OPT::Apply (*A_, z_cur, v_cur);
00185   }
00186       else
00187   { // In this case, the right preconditioner is the identity
00188     // operator, so we only have to copy v_prv into z_cur.
00189     MVT::Assign (v_prv, z_cur);
00190     OPT::Apply (*A_, z_cur, v_cur);
00191   }
00192     }
00193 
00194   private:
00196     int validatedBasisLength (const int len) const {
00197       if (len < 1)
00198   throw std::invalid_argument("Invalid recommended candidate basis length");
00199       else
00200   return len;
00201     }
00202 
00204     Teuchos::RCP<const OP> A_;
00206     Teuchos::RCP<const OP> M_left_;
00208     Teuchos::RCP<const OP> M_right_;
00219     Teuchos::RCP<const MV> v_scratch_;
00220 
00222     int recommendedBasisLength_
00223   };
00224 
00225 } // namespace Belos
00226 
00227 #endif // __Belos_OpAkx_hpp
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Defines