reflections Namespace Reference

Functions
template<unsigned int Precision>
void	generatereflection (ap::template_1d_array< amp::ampf< Precision > > &x, int n, amp::ampf< Precision > &tau)
template<unsigned int Precision>
void	applyreflectionfromtheleft (ap::template_2d_array< amp::ampf< Precision > > &c, amp::ampf< Precision > tau, const ap::template_1d_array< amp::ampf< Precision > > &v, int m1, int m2, int n1, int n2, ap::template_1d_array< amp::ampf< Precision > > &work)
template<unsigned int Precision>
void	applyreflectionfromtheright (ap::template_2d_array< amp::ampf< Precision > > &c, amp::ampf< Precision > tau, const ap::template_1d_array< amp::ampf< Precision > > &v, int m1, int m2, int n1, int n2, ap::template_1d_array< amp::ampf< Precision > > &work)

Function Documentation

applyreflectionfromtheleft()

template<unsigned int Precision>

void reflections::applyreflectionfromtheleft	(	ap::template_2d_array< amp::ampf< Precision > > &	c,
		amp::ampf< Precision >	tau,
		const ap::template_1d_array< amp::ampf< Precision > > &	v,
		int	m1,
		int	m2,
		int	n1,
		int	n2,
		ap::template_1d_array< amp::ampf< Precision > > &	work
	)

Definition at line 207 of file reflections.h.

    {
        amp::ampf<Precision> t;
        int i;
        int vm;
 
 
        if( tau==0 || n1>n2 || m1>m2 )
        {
            return;
        }
 
        //
        // w := C' * v
        //
        vm = m2-m1+1;
        for(i=n1; i<=n2; i++)
        {
            work(i) = 0;
        }
        for(i=m1; i<=m2; i++)
        {
            t = v(i+1-m1);
            ap::vadd(work.getvector(n1, n2), c.getrow(i, n1, n2), t);
        }
 
        //
        // C := C - tau * v * w'
        //
        for(i=m1; i<=m2; i++)
        {
            t = v(i-m1+1)*tau;
            ap::vsub(c.getrow(i, n1, n2), work.getvector(n1, n2), t);
        }
    }

applyreflectionfromtheright()

template<unsigned int Precision>

void reflections::applyreflectionfromtheright	(	ap::template_2d_array< amp::ampf< Precision > > &	c,
		amp::ampf< Precision >	tau,
		const ap::template_1d_array< amp::ampf< Precision > > &	v,
		int	m1,
		int	m2,
		int	n1,
		int	n2,
		ap::template_1d_array< amp::ampf< Precision > > &	work
	)

Definition at line 280 of file reflections.h.

    {
        amp::ampf<Precision> t;
        int i;
        int vm;
 
 
        if( tau==0 || n1>n2 || m1>m2 )
        {
            return;
        }
 
        //
        // w := C * v
        //
        vm = n2-n1+1;
        for(i=m1; i<=m2; i++)
        {
            t = ap::vdotproduct(c.getrow(i, n1, n2), v.getvector(1, vm));
            work(i) = t;
        }
 
        //
        // C := C - w * v'
        //
        for(i=m1; i<=m2; i++)
        {
            t = work(i)*tau;
            ap::vsub(c.getrow(i, n1, n2), v.getvector(1, vm), t);
        }
    }

generatereflection()

template<unsigned int Precision>

void reflections::generatereflection	(	ap::template_1d_array< amp::ampf< Precision > > &	x,
		int	n,
		amp::ampf< Precision > &	tau
	)

Definition at line 112 of file reflections.h.

    {
        int j;
        amp::ampf<Precision> alpha;
        amp::ampf<Precision> xnorm;
        amp::ampf<Precision> v;
        amp::ampf<Precision> beta;
        amp::ampf<Precision> mx;
 
 
 
        //
        // Executable Statements ..
        //
        if( n<=1 )
        {
            tau = 0;
            return;
        }
 
        //
        // XNORM = DNRM2( N-1, X, INCX )
        //
        alpha = x(1);
        mx = 0;
        for(j=2; j<=n; j++)
        {
            mx = amp::maximum<Precision>(amp::abs<Precision>(x(j)), mx);
        }
        xnorm = 0;
        if( mx!=0 )
        {
            for(j=2; j<=n; j++)
            {
                xnorm = xnorm+amp::sqr<Precision>(x(j)/mx);
            }
            xnorm = amp::sqrt<Precision>(xnorm)*mx;
        }
        if( xnorm==0 )
        {
 
            //
            // H  =  I
            //
            tau = 0;
            return;
        }
 
        //
        // general case
        //
        mx = amp::maximum<Precision>(amp::abs<Precision>(alpha), amp::abs<Precision>(xnorm));
        beta = -mx*amp::sqrt<Precision>(amp::sqr<Precision>(alpha/mx)+amp::sqr<Precision>(xnorm/mx));
        if( alpha<0 )
        {
            beta = -beta;
        }
        tau = (beta-alpha)/beta;
        v = 1/(alpha-beta);
        ap::vmul(x.getvector(2, n), v);
        x(1) = beta;
    }