lsst::jointcal::StarMatchList Class Reference

#include <StarMatch.h>

Inheritance diagram for lsst::jointcal::StarMatchList:

Public Member Functions
void	refineTransform (double nSigmas)
	removes pairs beyond nSigmas in distance (where the sigma scale is set by the fit) and iterates until stabilization of the number of pairs.
void	applyTransform (StarMatchList &transformed, const AstrometryTransform *priorTransform, const AstrometryTransform *posteriorTransform=nullptr) const
	enables to get a transformed StarMatchList.
	StarMatchList ()
std::shared_ptr< const AstrometryTransform >	getTransform () const
	carries out a fit with outlier rejection
double	getDist2 () const
	access to the sum of squared residuals of the last call to refineTransform.
double	getChi2 () const
	access to the chi2 of the last call to refineTransform.
int	getTransformOrder () const
	returns the order of the used transform
void	swap ()
	swaps elements 1 and 2 of each starmatch in std::list.
double	computeResidual () const
	returns the average 1d Residual (last call to refineTransform)
unsigned	removeAmbiguities (const AstrometryTransform &transform, int which=3)
	cleans up the std::list of pairs for pairs that share one of their stars, keeping the closest one.
void	setTransform (const AstrometryTransform *transform)
	sets a transform between the 2 std::lists and deletes the previous or default one. No fit.
void	setTransform (const AstrometryTransform &transform)
void	setTransform (std::shared_ptr< AstrometryTransform > transform)
void	setTransformOrder (int order)
	set transform according to the given order.
std::unique_ptr< AstrometryTransform >	inverseTransform ()
	returns the inverse transform (swap, fit(refineTransform) , and swap).
void	setDistance (const AstrometryTransform &transform)
	Sets the distance (residual) field of all std::list elements. Mandatory before sorting on distances.
void	cutTail (int nKeep)
	deletes the tail of the match std::list
int	recoveredNumber (double mindist) const
	count the number of elements for which distance is < mindist
void	printTransform (std::ostream &stream=std::cout) const
	print the matching transformation quality (transform, chi2, residual)
	~StarMatchList ()=default
	StarMatchList (const StarMatchList &)=delete
void	operator= (const StarMatchList &)=delete
StarMatch	pop_front (StarMatch ... args)
StarMatch	push_back (StarMatch ... args)
StarMatch	splice (StarMatch ... args)
StarMatch	crbegin (StarMatch ... args)
StarMatch	erase (StarMatch ... args)
StarMatch	emplace_front (StarMatch ... args)
StarMatch	insert (StarMatch ... args)
StarMatch	reverse (StarMatch ... args)
StarMatch	back (StarMatch ... args)
StarMatch	end (StarMatch ... args)
StarMatch	remove (StarMatch ... args)
StarMatch	emplace_back (StarMatch ... args)
StarMatch	pop_back (StarMatch ... args)
StarMatch	cbegin (StarMatch ... args)
StarMatch	front (StarMatch ... args)
StarMatch	unique (StarMatch ... args)
StarMatch	size (StarMatch ... args)
StarMatch	resize (StarMatch ... args)
StarMatch	push_front (StarMatch ... args)
StarMatch	rbegin (StarMatch ... args)
StarMatch	crend (StarMatch ... args)
StarMatch	assign (StarMatch ... args)
StarMatch	sort (StarMatch ... args)
StarMatch	merge (StarMatch ... args)
StarMatch	empty (StarMatch ... args)
StarMatch	remove_if (StarMatch ... args)
StarMatch	cend (StarMatch ... args)
StarMatch	swap (StarMatch ... args)
StarMatch	max_size (StarMatch ... args)
StarMatch	rend (StarMatch ... args)
StarMatch	get_allocator (StarMatch ... args)
StarMatch	clear (StarMatch ... args)
StarMatch	emplace (StarMatch ... args)
StarMatch	begin (StarMatch ... args)

Public Attributes
StarMatch	elements
	STL member.

Detailed Description

Definition at line 150 of file StarMatch.h.

Constructor & Destructor Documentation

StarMatchList() [1/2]

lsst::jointcal::StarMatchList::StarMatchList ( )

inline

Definition at line 160 of file StarMatch.h.

: _order(0), _chi2(0){};

~StarMatchList()

lsst::jointcal::StarMatchList::~StarMatchList ( )

default

StarMatchList() [2/2]

lsst::jointcal::StarMatchList::StarMatchList ( const StarMatchList & )

delete

Member Function Documentation

applyTransform()

void lsst::jointcal::StarMatchList::applyTransform	(	StarMatchList &	transformed,
		const AstrometryTransform *	priorTransform,
		const AstrometryTransform *	posteriorTransform = nullptr ) const

enables to get a transformed StarMatchList.

Only positions are transformed, not attached stars. const routine: "this" remains unchanged.

Definition at line 212 of file StarMatch.cc.

                                                                                        {
    transformed.clear();
    AstrometryTransformIdentity id;
    const AstrometryTransform &T1 = (priorTransform) ? *priorTransform : id;
    const AstrometryTransform &T2 = (posteriorTransform) ? *posteriorTransform : id;
 
    for (auto const &starMatch : *this) {
        FatPoint p1;
        T1.transformPosAndErrors(starMatch.point1, p1);
        FatPoint p2;
        T2.transformPosAndErrors(starMatch.point2, p2);
        transformed.push_back(StarMatch(p1, p2, starMatch.s1, starMatch.s2));
    }
}

computeResidual()

double lsst::jointcal::StarMatchList::computeResidual

(

)

const

returns the average 1d Residual (last call to refineTransform)

Definition at line 134 of file StarMatch.cc.

                                            {
    int deno = (2. * size() - _transform->getNpar());
    return (deno > 0) ? sqrt(_dist2 / deno) : -1;  // is -1 a good idea?
}

cutTail()

void lsst::jointcal::StarMatchList::cutTail

(

int

nKeep

)

deletes the tail of the match std::list

Definition at line 189 of file StarMatch.cc.

                                     {
    iterator si;
    int count = 0;
    for (si = begin(); si != end() && count < nKeep; ++count, ++si)
        ;
    erase(si, end());
}

getChi2()

double lsst::jointcal::StarMatchList::getChi2 ( ) const

inline

access to the chi2 of the last call to refineTransform.

Definition at line 171 of file StarMatch.h.

{ return _chi2; }

getDist2()

double lsst::jointcal::StarMatchList::getDist2 ( ) const

inline

access to the sum of squared residuals of the last call to refineTransform.

Definition at line 168 of file StarMatch.h.

{ return _dist2; }

getTransform()

std::shared_ptr< const AstrometryTransform > lsst::jointcal::StarMatchList::getTransform ( ) const

inline

carries out a fit with outlier rejection

enables to access the fitted transformation.

Definition at line 165 of file StarMatch.h.

{ return _transform; }

getTransformOrder()

int lsst::jointcal::StarMatchList::getTransformOrder ( ) const

inline

returns the order of the used transform

Definition at line 174 of file StarMatch.h.

{ return _order; }

inverseTransform()

std::unique_ptr< AstrometryTransform > lsst::jointcal::StarMatchList::inverseTransform

(

)

returns the inverse transform (swap, fit(refineTransform) , and swap).

The caller should delete the returned pointer.

Definition at line 172 of file StarMatch.cc.

                                                                   {
    if (!_transform) return nullptr;
 
    auto old_transform = _transform->clone();
    double old_chi2 = _chi2;
 
    swap();
    setTransformOrder(_order);
    refineTransform(3.);  // keep same order
    auto inverted_transform = _transform->clone();
    setTransform(old_transform.get());
    swap();
    _chi2 = old_chi2;
 
    return inverted_transform;
}

operator=()

void lsst::jointcal::StarMatchList::operator= ( const StarMatchList & )

delete

printTransform()

void lsst::jointcal::StarMatchList::printTransform

(

std::ostream &

stream = std::cout

)

const

print the matching transformation quality (transform, chi2, residual)

Definition at line 228 of file StarMatch.cc.

                                                           {
    stream << " ================================================================" << std::endl
           << " Transformation between lists of order " << getTransformOrder() << std::endl
           << *_transform  //<< endl
           << " Chi2 = " << getChi2() << "  Residual = " << computeResidual() << std::endl
           << "  Number in the list = " << size() << std::endl
           << " ================================================================" << std::endl;
}

recoveredNumber()

int lsst::jointcal::StarMatchList::recoveredNumber

(

double

mindist

)

const

count the number of elements for which distance is < mindist

Definition at line 203 of file StarMatch.cc.

                                                       {
    int n = 0;
    AstrometryTransformIdentity identity;
    for (auto const &starMatch : *this) {
        if (starMatch.computeDistance(identity) < mindist) n++;
    }
    return (n);
}

refineTransform()

void lsst::jointcal::StarMatchList::refineTransform

(

double

nSigmas

)

removes pairs beyond nSigmas in distance (where the sigma scale is set by the fit) and iterates until stabilization of the number of pairs.

If the transform is not assigned, it will be set to a AstrometryTransformLinearear. User can set an other type/order using setTransform() before call.

Definition at line 92 of file StarMatch.cc.

                                                  {
    double cut;
    unsigned nremoved;
    if (!_transform) _transform.reset(new AstrometryTransformLinear);
    do {
        int nused = size();
        if (nused <= 2) {
            _chi2 = -1;
            break;
        }
        _chi2 = _transform->fit(*this);
        /* convention of the fitted routines :
           -  chi2 = 0 means zero degrees of freedom
                (this was not enforced in AstrometryTransform{Lin,Quad,Cub} ...)
           -  chi2 = -1 means ndof <0 (and hence no possible fit)
           --> in either case, refinement is over
           The fact that chi2 = 0 was not enforced when necessary means
           that in this (rare) case, we were discarding matches at random....
           With AstrometryTransformPolynomial::fit, this is no longer the case.
        */
        if (_chi2 <= 0) return;
        unsigned npair = int(size());
        if (npair == 0) break;  // should never happen
 
        // compute some chi2 statistics
        std::vector<double> chi2_array(npair);
        unsigned count = 0;
        for (auto &starMatch : *this)
            chi2_array[count++] = starMatch.chi2 = starMatch.computeChi2(*_transform);
 
        std::sort(chi2_array.begin(), chi2_array.end());
        double median = (npair & 1) ? chi2_array[npair / 2]
                                    : (chi2_array[npair / 2 - 1] + chi2_array[npair / 2]) * 0.5;
 
        // discard outliers : the cut is understood as a "distance" cut
        cut = sq(nSigmas) * median;
        nremoved = chi2_cleanup(*this, cut, *_transform);
    } while (nremoved);
    _dist2 = computeDist2(*this, *_transform);
}

removeAmbiguities()

unsigned lsst::jointcal::StarMatchList::removeAmbiguities	(	const AstrometryTransform &	transform,
		int	which = 3 )

cleans up the std::list of pairs for pairs that share one of their stars, keeping the closest one.

The distance is computed using transform. which = 1 (2) removes ambiguities on the first (second) term of the match. which=3 does both.

Definition at line 143 of file StarMatch.cc.

                                                                                         {
    if (!which) return 0;
    setDistance(transform);
    int initial_count = size();
    if (which & 1) {
        sort(compareStar1);
        unique(sameStar1);
    }
    if (which & 2) {
        sort(compareStar2);
        unique(sameStar2);
    }
    return (initial_count - size());
}

setDistance()

void lsst::jointcal::StarMatchList::setDistance

(

const AstrometryTransform &

transform

)

Sets the distance (residual) field of all std::list elements. Mandatory before sorting on distances.

Definition at line 139 of file StarMatch.cc.

                                                                    {
    for (auto &smi : *this) smi.setDistance(transform);  // c'est compact
}

setTransform() [1/3]

void lsst::jointcal::StarMatchList::setTransform ( const AstrometryTransform & transform )

inline

Definition at line 190 of file StarMatch.h.

{ _transform = transform.clone(); }

setTransform() [2/3]

void lsst::jointcal::StarMatchList::setTransform ( const AstrometryTransform * transform )

inline

sets a transform between the 2 std::lists and deletes the previous or default one. No fit.

Definition at line 188 of file StarMatch.h.

{ _transform = transform->clone(); }

setTransform() [3/3]

void lsst::jointcal::StarMatchList::setTransform ( std::shared_ptr< AstrometryTransform > transform )

inline

Definition at line 191 of file StarMatch.h.

{ _transform = std::move(transform); }

setTransformOrder()

void lsst::jointcal::StarMatchList::setTransformOrder

(

int

order

)

set transform according to the given order.

Definition at line 158 of file StarMatch.cc.

                                               {
    if (order == 0)
        setTransform(std::make_shared<AstrometryTransformLinearShift>());
    else if (order == 1)
        setTransform(std::make_shared<AstrometryTransformLinear>());
    else
        setTransform(AstrometryTransformPolynomial(order));
    // might consider throwing if order does not make sense (e.g. >10)
    _order = order;
}

swap()

void lsst::jointcal::StarMatchList::swap

(

)

swaps elements 1 and 2 of each starmatch in std::list.

Definition at line 197 of file StarMatch.cc.

                         {
    for (auto &starMatch : *this) {
        starMatch.swap();
    }
}

Member Data Documentation

elements

StarMatch std::list< StarMatch >::elements

inherited

STL member.

---

The documentation for this class was generated from the following files:

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-9.0.0/Linux64/jointcal/g82479be7b0+d730eedb7d/include/lsst/jointcal/StarMatch.h
• /j/snowflake/release/lsstsw/stack/lsst-scipipe-9.0.0/Linux64/jointcal/g82479be7b0+d730eedb7d/src/StarMatch.cc