diagmatrix.h

//-*- c++ -*-
//
// Copyright (C) 2009 Tom Drummond (twd20@cam.ac.uk),
// Ed Rosten (er258@cam.ac.uk)

//All rights reserved.
//
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//modification, are permitted provided that the following conditions
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//   notice, this list of conditions and the following disclaimer in the
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namespace TooN {

    namespace Internal
    {
        //Dummy struct for Diagonal operator
        template<int Size, typename Precision, typename Base>
        struct DiagMatrixOp;
    }

    template<int Size, typename Precision, typename Base>
    struct Operator<Internal::DiagMatrixOp<Size, Precision, Base> >
    {
        public:


        inline Operator() {}
        inline Operator(int size_in) : my_vector(size_in) {}
        inline Operator(Precision* data) : my_vector(data) {}
        inline Operator(Precision* data, int size_in) : my_vector(data,size_in) {}
        inline Operator(Precision* data_in, int size_in, int stride_in, Internal::Slicing)
            : my_vector(data_in, size_in, stride_in, Internal::Slicing() ) {}

        // constructors to allow return value optimisations
        // construction from 0-ary operator
        template <class Op>
        inline Operator(const Operator<Op>& op)
            : my_vector (op)
        {
            op.eval(my_vector);
        }
        
        // constructor from arbitrary vector
        template<int Size2, typename Precision2, typename Base2>
        inline Operator(const Vector<Size2,Precision2,Base2>& from)
            : my_vector(from.size())
        {
            my_vector=from;
        }


        template<int R, int C, class P, class B>
        void eval(Matrix<R,C,P,B>& m) const {
            SizeMismatch<Size, Size>::test(m.num_rows(), m.num_cols());
            m = Zeros;
            m.diagonal_slice() = my_vector;
        }

        Vector<Size,Precision,Base> my_vector;
    };

template<int Size=Dynamic, typename Precision=DefaultPrecision, typename Base=Internal::VBase>
struct DiagonalMatrix: public Operator<Internal::DiagMatrixOp<Size, Precision, Base> > {
public:
    
    inline DiagonalMatrix() {}
    inline DiagonalMatrix(int size_in) : Operator<Internal::DiagMatrixOp<Size, Precision, Base> >(size_in) {}
    inline DiagonalMatrix(Precision* data) : Operator<Internal::DiagMatrixOp<Size, Precision, Base> >(data) {}
    inline DiagonalMatrix(Precision* data, int size_in) : Operator<Internal::DiagMatrixOp<Size, Precision, Base> >(data,size_in) {}
    inline DiagonalMatrix(Precision* data_in, int size_in, int stride_in, Internal::Slicing)
        : Operator<Internal::DiagMatrixOp<Size, Precision, Base> >(data_in, size_in, stride_in, Internal::Slicing() ) {}

    // constructors to allow return value optimisations
    // construction from 0-ary operator
    template <class Op>
    inline DiagonalMatrix(const Operator<Op>& op)
        : Operator<Internal::DiagMatrixOp<Size, Precision, Base> > (op)
    {
        op.eval(this->my_vector);
    }
    
    // constructor from arbitrary vector
    template<int Size2, typename Precision2, typename Base2>
    inline DiagonalMatrix(const Vector<Size2,Precision2,Base2>& from)
        : Operator<Internal::DiagMatrixOp<Size, Precision, Base> >(from.size())
    {
        this->my_vector=from;
    }



    Precision& operator[](int i){return this->my_vector[i];}
    const Precision& operator[](int i) const {return this->my_vector[i];}
    
    typename Vector<Size, Precision, Base>::as_slice_type diagonal_slice() {
        return this->my_vector.as_slice();
    }

    const typename Vector<Size, Precision, Base>::as_slice_type diagonal_slice() const {
        return this->my_vector.as_slice();
    }

    DiagonalMatrix<Size, Precision> operator-() const
    {
        return -this->my_vector;
    }

    DiagonalMatrix<Size, Precision> inverse() const
    {
        Vector<Size, Precision> inv(this->my_vector.size());
        for(int i=0; i < inv.size(); i++)
            inv[i] = 1 / this->my_vector[i];
        return inv;
    }
};


template<int S1, typename P1, typename B1, int S2, typename P2, typename B2>
inline Vector<Internal::Sizer<S1,S2>::size, typename Internal::MultiplyType<P1,P2>::type>
operator*(const DiagonalMatrix<S1,P1,B1>& d, const Vector<S2,P2,B2>& v){
    return diagmult(d.my_vector,v);
}

template<int S1, typename P1, typename B1, int S2, typename P2, typename B2>
inline Vector<Internal::Sizer<S1,S2>::size, typename Internal::MultiplyType<P1,P2>::type>
operator*( const Vector<S1,P1,B1>& v, const DiagonalMatrix<S2,P2,B2>& d){
    return diagmult(v,d.my_vector);
}

// perhaps not the safest way to do this as we're returning the same operator used to normally make vectors
template<int S1, typename P1, typename B1, int S2, typename P2, typename B2>
inline DiagonalMatrix<Internal::Sizer<S1,S2>::size, typename Internal::MultiplyType<P1,P2>::type>
operator*( const DiagonalMatrix<S1,P1,B1>& d1, const DiagonalMatrix<S2,P2,B2>& d2){
    SizeMismatch<S1,S2>::test(d1.my_vector.size(),d2.my_vector.size());
    return Operator<Internal::VPairwise<Internal::Multiply,S1,P1,B1,S2,P2,B2> >(d1.my_vector,d2.my_vector);
}

template<int R, int C, int Size, typename P1, typename P2, typename B1, typename B2>
Matrix<R, C, typename Internal::MultiplyType<P1,P2>::type>
operator* (const Matrix<R, C, P1, B1>& m, const DiagonalMatrix<Size, P2, B2>& d){
    return diagmult(m,d.my_vector);
}

template<int R, int C, typename P1, typename B1, int Size, typename P2, typename B2> 
Matrix<R, C, typename Internal::MultiplyType<P1,P2>::type>
operator* (const DiagonalMatrix<Size,P1,B1>& d, const Matrix<R,C,P2,B2>& m)
{
    return diagmult(d.my_vector, m);
}

}