gsConjugateGradient.h

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#pragma once
 
#include <gsSolver/gsIterativeSolver.h>
 
namespace gismo
{
 
template<class T = real_t>
class gsConjugateGradient : public gsIterativeSolver<T>
{
public:
    typedef gsIterativeSolver<T> Base;
 
    typedef gsMatrix<T>  VectorType;
 
    typedef typename Base::LinOpPtr LinOpPtr;
 
    typedef memory::shared_ptr<gsConjugateGradient> Ptr;
    typedef memory::unique_ptr<gsConjugateGradient> uPtr;
 
    template< typename OperatorType >
    explicit gsConjugateGradient( const OperatorType& mat,
                                  const LinOpPtr& precond = LinOpPtr() )
    : Base(mat, precond), m_calcEigenvals(false) {}
 
    template< typename OperatorType >
    static uPtr make( const OperatorType& mat, const LinOpPtr& precond = LinOpPtr() )
    { return uPtr( new gsConjugateGradient(mat, precond) ); }
 
    static gsOptionList defaultOptions()
    {
        gsOptionList opt = Base::defaultOptions();
        opt.addSwitch("CalcEigenvalues", "Additionally to solving the system,"
                      " CG computes the eigenvalues of the Lanczos matrix", false );
        return opt;
    }
 
    gsConjugateGradient& setOptions(const gsOptionList& opt)
    {
        Base::setOptions(opt);
        m_calcEigenvals = opt.askSwitch("CalcEigenvalues", m_calcEigenvals);
        return *this;
    }
 
    bool initIteration( const VectorType& rhs, VectorType& x );
    bool step( VectorType& x );
 
    void setCalcEigenvalues( bool flag )     { m_calcEigenvals = flag ;}
 
    T getConditionNumber();
 
    void getEigenvalues( VectorType& eigs );
 
    std::ostream &print(std::ostream &os) const
    {
        os << "gsConjugateGradient\n";
        return os;
    }
 
private:
    using Base::m_mat;
    using Base::m_precond;
    using Base::m_max_iters;
    using Base::m_tol;
    using Base::m_num_iter;
    using Base::m_rhs_norm;
    using Base::m_error;
 
 
    VectorType m_res;
    VectorType m_update;
    VectorType m_tmp;
    T m_abs_new;
 
    bool m_calcEigenvals;
 
    std::vector<T> m_delta, m_gamma;
};
 
} // namespace gismo
 
#ifndef GISMO_BUILD_LIB
#include GISMO_HPP_HEADER(gsConjugateGradient.hpp)
#endif