@q $Id: product.cweb 431 2005-08-16 15:41:01Z kamenik $ @>
@q Copyright 2005, Ondra Kamenik @>

@ This is {\tt product.cpp} file.

@c
#include "product.h"
#include "symmetry.h"

@<|prodpit| empty constructor@>;
@<|prodpit| regular constructor@>;
@<|prodpit| copy constructor@>;
@<|prodpit| destructor@>;
@<|prodpit::operator==| code@>;
@<|prodpit::operator=| code@>;
@<|prodpit::operator++| code@>;
@<|prodpit::setPointAndWeight| code@>;
@<|prodpit::print| code@>;
@<|ProductQuadrature| constructor@>;
@<|ProductQuadrature::begin| code@>;
@<|ProductQuadrature::designLevelForEvals| code@>;

@ 
@<|prodpit| empty constructor@>=
prodpit::prodpit()
	: prodq(NULL), level(0), npoints(0), jseq(NULL),
	  end_flag(true), sig(NULL), p(NULL)
{
}

@ This constructs a product iterator corresponding to index $(j0,0\ldots,0)$.
@<|prodpit| regular constructor@>=
prodpit::prodpit(const ProductQuadrature& q, int j0, int l)
	: prodq(&q), level(l), npoints(q.uquad.numPoints(l)), jseq(new IntSequence(q.dimen(), 0)),
	  end_flag(false), sig(new ParameterSignal(q.dimen())), p(new Vector(q.dimen()))
{
	if (j0 < npoints) {
		(*jseq)[0] = j0;
		setPointAndWeight();
	} else {
		end_flag = true;
	}
}

@ Copy constructor, clear.
@<|prodpit| copy constructor@>=
prodpit::prodpit(const prodpit& ppit)
	: prodq(ppit.prodq), level(ppit.level), npoints(ppit.npoints),
	  end_flag(ppit.end_flag), w(ppit.w)
{
	if (ppit.jseq)
		jseq = new IntSequence(*(ppit.jseq));
	else
		jseq = NULL;
	if (ppit.sig)
		sig = new ParameterSignal(*(ppit.sig));
	else
		sig = NULL;
	if (ppit.p)
		p = new Vector(*(ppit.p));
	else
		p = NULL;
}

@ 
@<|prodpit| destructor@>=
prodpit::~prodpit()
{
	if (jseq)
		delete jseq;
	if (sig)
		delete sig;
	if (p)
		delete p;
}

@ 
@<|prodpit::operator==| code@>=
bool prodpit::operator==(const prodpit& ppit) const
{
	bool ret = true;
	ret = ret & prodq == ppit.prodq;
	ret = ret & end_flag == ppit.end_flag;
	ret = ret & ((jseq==NULL && ppit.jseq==NULL) ||
				 (jseq!=NULL && ppit.jseq!=NULL && *jseq == *(ppit.jseq)));
	return ret;
}

@ 
@<|prodpit::operator=| code@>=
const prodpit& prodpit::operator=(const prodpit& ppit)
{
	prodq = ppit.prodq;
	end_flag = ppit.end_flag;
	w = ppit.w;

	if (jseq)
		delete jseq;
	if (sig)
		delete sig;
	if (p)
		delete p;

	if (ppit.jseq)
		jseq = new IntSequence(*(ppit.jseq));
	else
		jseq = NULL;
	if (ppit.sig)
		sig = new ParameterSignal(*(ppit.sig));
	else
		sig = NULL;
	if (ppit.p)
		p = new Vector(*(ppit.p));
	else
		p = NULL;

	return *this;
}

@ 
@<|prodpit::operator++| code@>=
prodpit& prodpit::operator++()
{
	// todo: throw if |prodq==NULL| or |jseq==NULL| or |sig==NULL| or |end_flag==true|
	int i = prodq->dimen()-1;
	(*jseq)[i]++;
	while (i >= 0 && (*jseq)[i] == npoints) {
		(*jseq)[i] = 0;
		i--;
		if (i >= 0)
			(*jseq)[i]++;
	}
	sig->signalAfter(std::max(i,0));

	if (i == -1)
		end_flag = true;

	if (! end_flag)
		setPointAndWeight();

	return *this;
}


@ This calculates the weight and sets point coordinates from the indices.
@<|prodpit::setPointAndWeight| code@>=
void prodpit::setPointAndWeight()
{
	// todo: raise if |prodq==NULL| or |jseq==NULL| or |sig==NULL| or
	// |p==NULL| or |end_flag==true|
	w = 1.0;
	for (int i = 0; i < prodq->dimen(); i++) {
		(*p)[i] = (prodq->uquad).point(level, (*jseq)[i]);
		w* = (prodq->uquad).weight(level, (*jseq)[i]);
	}
}

@ Debug print.
@<|prodpit::print| code@>=
void prodpit::print() const
{
	printf("j=[");
	for (int i = 0; i < prodq->dimen(); i++)
		printf("%2d ", (*jseq)[i]);
	printf("] %+4.3f*(",w);
	for (int i = 0; i < prodq->dimen()-1; i++)
		printf("%+4.3f ", (*p)[i]);
	printf("%+4.3f)\n",(*p)[prodq->dimen()-1]);
}

@ 
@<|ProductQuadrature| constructor@>=
ProductQuadrature::ProductQuadrature(int d, const OneDQuadrature& uq)
	: QuadratureImpl<prodpit>(d), uquad(uq)
{
	// todo: check |d>=1|
}

@ This calls |prodpit| constructor to return an iterator which points
approximatelly at |ti|-th portion out of |tn| portions. First we find
out how many points are in the level, and then construct an interator
$(j0,0,\ldots,0)$ where $j0=$|ti*npoints/tn|.

@<|ProductQuadrature::begin| code@>=
prodpit ProductQuadrature::begin(int ti, int tn, int l) const
{
	// todo: raise is |l<dimen()|
	// todo: check |l<=uquad.numLevels()|
	int npoints = uquad.numPoints(l);
	return prodpit(*this, ti*npoints/tn, l);
}

@ This just starts at the first level and goes to a higher level as
long as a number of evaluations (which is $n_k^d$ for $k$ being the
level) is less than the given number of evaluations.

@<|ProductQuadrature::designLevelForEvals| code@>=
void ProductQuadrature::designLevelForEvals(int max_evals, int& lev, int& evals) const
{
	int last_evals;
	evals = 1;
	lev = 1;
	do {
		lev++;
		last_evals = evals;
		evals = numEvals(lev);
	} while (lev < uquad.numLevels()-2 && evals < max_evals);
	lev--;
	evals = last_evals;

}

@ End of {\tt product.cpp} file