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Public Member Functions | List of all members
lsst::jointcal::AstrometryTransform Class Referenceabstract

a virtual (interface) class for geometric transformations. More...

#include <AstrometryTransform.h>

Inheritance diagram for lsst::jointcal::AstrometryTransform:
lsst::jointcal::AstrometryTransformComposition lsst::jointcal::AstrometryTransformIdentity lsst::jointcal::AstrometryTransformInverse lsst::jointcal::AstrometryTransformPolynomial lsst::jointcal::AstrometryTransformSkyWcs lsst::jointcal::BaseTanWcs lsst::jointcal::TanRaDecToPixel lsst::jointcal::UserTransform

Public Member Functions

virtual void apply (double xIn, double yIn, double &xOut, double &yOut) const =0
 
void apply (Point const &in, Point &out) const
 applies the tranfo to in and writes into out. Is indeed virtual.
 
Point apply (Point const &in) const
 All these apply(..) shadow the virtual one in derived classes, unless one writes "using AstrometryTransform::apply".
 
Frame apply (Frame const &inputframe, bool inscribed) const
 Transform a bounding box, taking either the inscribed or circumscribed box.
 
virtual void print (std::ostream &out) const =0
 prints the transform coefficients to stream.
 
std::string __str__ () const
 
virtual double fit (StarMatchList const &starMatchList)=0
 fits a transform to a std::list of Point pairs (p1,p2, the Point fields in StarMatch).
 
void transformStar (FatPoint &in) const
 
virtual double getJacobian (Point const &point) const
 returns the local jacobian.
 
virtual std::unique_ptr< AstrometryTransformclone () const =0
 returns a copy (allocated by new) of the transformation.
 
virtual std::unique_ptr< AstrometryTransformcomposeAndReduce (AstrometryTransform const &right) const
 Return a reduced composition of newTransform = this(right()), or nullptr if it cannot be reduced.
 
virtual double getJacobian (double x, double y) const
 returns the local jacobian.
 
virtual void computeDerivative (Point const &where, AstrometryTransformLinear &derivative, double step=0.01) const
 Computes the local Derivative of a transform, w.r.t.
 
virtual AstrometryTransformLinear linearApproximation (Point const &where, double step=0.01) const
 linear (local) approximation.
 
virtual void transformPosAndErrors (const FatPoint &in, FatPoint &out) const
 
virtual void transformErrors (Point const &where, const double *vIn, double *vOut) const
 transform errors (represented as double[3] in order V(xx),V(yy),Cov(xy))
 
virtual std::unique_ptr< AstrometryTransforminverseTransform (double precision, const Frame &region) const
 returns an inverse transform. Numerical if not overloaded.
 
void getParams (double *params) const
 params should be at least Npar() long
 
void offsetParams (Eigen::VectorXd const &delta)
 
virtual double paramRef (Eigen::Index i) const
 
virtual double & paramRef (Eigen::Index i)
 
virtual void paramDerivatives (Point const &where, double *dx, double *dy) const
 Derivative w.r.t parameters.
 
virtual std::unique_ptr< AstrometryTransformroughInverse (const Frame &region) const
 Rough inverse.
 
virtual std::size_t getNpar () const
 returns the number of parameters (to compute chi2's)
 
virtual std::shared_ptr< ast::MappingtoAstMap (jointcal::Frame const &domain) const
 Create an equivalent AST mapping for this transformation, including an analytic inverse if possible.
 
void write (const std::string &fileName) const
 
virtual void write (std::ostream &stream) const
 
virtual ~AstrometryTransform ()=default
 

Detailed Description

a virtual (interface) class for geometric transformations.

We implement here One AstrometryTransform interface class, and actual derived classes. Composition in the usual (mathematical) sense is provided using compose(), and some classes (e.g. AstrometryTransformLinear) handle a * operator. Generic inversion by iteration exists, but it is at least 10 times slower than the corresponding "direct transformation". If a transform has an analytical inverse, then providing inverseTransform is obviously a very good idea. Before resorting to inverseTransform, consider using StarMatchList::inverseTransform(). AstrometryTransformLinear::inverted() and TanPixelToRaDec::inverted() exist. The classes also provide derivation and linear approximation.

Definition at line 65 of file AstrometryTransform.h.

Constructor & Destructor Documentation

◆ ~AstrometryTransform()

virtual lsst::jointcal::AstrometryTransform::~AstrometryTransform ( )
virtualdefault

Member Function Documentation

◆ __str__()

std::string lsst::jointcal::AstrometryTransform::__str__ ( ) const
inline

Definition at line 94 of file AstrometryTransform.h.

94 {
96 print(s);
97 return s.str();
98 }
virtual void print(std::ostream &out) const =0
prints the transform coefficients to stream.

◆ apply() [1/4]

virtual void lsst::jointcal::AstrometryTransform::apply ( double xIn,
double yIn,
double & xOut,
double & yOut ) const
pure virtual

◆ apply() [2/4]

Frame lsst::jointcal::AstrometryTransform::apply ( Frame const & inputframe,
bool inscribed ) const

Transform a bounding box, taking either the inscribed or circumscribed box.

Parameters
[in]inputframeThe frame to be transformed.
[in]inscribedReturn the inscribed (true) or circumscribed (false) box.
Returns
The transformed frame.

Definition at line 77 of file AstrometryTransform.cc.

77 {
78 // 2 opposite corners
79 double xtmin1, xtmax1, ytmin1, ytmax1;
80 apply(inputframe.xMin, inputframe.yMin, xtmin1, ytmin1);
81 apply(inputframe.xMax, inputframe.yMax, xtmax1, ytmax1);
82 Frame fr1(std::min(xtmin1, xtmax1), std::min(ytmin1, ytmax1), std::max(xtmin1, xtmax1),
83 std::max(ytmin1, ytmax1));
84 // 2 other corners
85 double xtmin2, xtmax2, ytmin2, ytmax2;
86 apply(inputframe.xMin, inputframe.yMax, xtmin2, ytmax2);
87 apply(inputframe.xMax, inputframe.yMin, xtmax2, ytmin2);
88 Frame fr2(std::min(xtmin2, xtmax2), std::min(ytmin2, ytmax2), std::max(xtmin2, xtmax2),
89 std::max(ytmin2, ytmax2));
90
91 if (inscribed) return fr1 * fr2;
92 return fr1 + fr2;
93}
virtual void apply(double xIn, double yIn, double &xOut, double &yOut) const =0
T max(T... args)
T min(T... args)

◆ apply() [3/4]

Point lsst::jointcal::AstrometryTransform::apply ( Point const & in) const
inline

All these apply(..) shadow the virtual one in derived classes, unless one writes "using AstrometryTransform::apply".

Definition at line 75 of file AstrometryTransform.h.

75 {
76 double xout, yout;
77 apply(in.x, in.y, xout, yout);
78 return Point(xout, yout);
79 }

◆ apply() [4/4]

void lsst::jointcal::AstrometryTransform::apply ( Point const & in,
Point & out ) const
inline

applies the tranfo to in and writes into out. Is indeed virtual.

Definition at line 71 of file AstrometryTransform.h.

71{ apply(in.x, in.y, out.x, out.y); }

◆ clone()

virtual std::unique_ptr< AstrometryTransform > lsst::jointcal::AstrometryTransform::clone ( ) const
pure virtual

◆ composeAndReduce()

std::unique_ptr< AstrometryTransform > lsst::jointcal::AstrometryTransform::composeAndReduce ( AstrometryTransform const & right) const
virtual

Return a reduced composition of newTransform = this(right()), or nullptr if it cannot be reduced.

"Reduced" in this context means that they are capable of being merged into a single transform, for example, for two polynomials:

\[ f(x) = 1 + x^2, g(x) = -1 + 3x \]

we would have h = f.composeAndReduce(g) == 2 - 6x + 9x^2.

To be overloaded by derived classes if they can properly reduce the composition.

Parameters
rightThe transform to apply first.
Returns
The new reduced and composed AstrometryTransform, or nullptr if no such reduction is possible.

Reimplemented in lsst::jointcal::AstrometryTransformPolynomial, lsst::jointcal::TanPixelToRaDec, and lsst::jointcal::AstrometryTransformIdentity.

Definition at line 95 of file AstrometryTransform.cc.

96 { // by default no way to compose
98}

◆ computeDerivative()

void lsst::jointcal::AstrometryTransform::computeDerivative ( Point const & where,
AstrometryTransformLinear & derivative,
double step = 0.01 ) const
virtual

Computes the local Derivative of a transform, w.r.t.

the Derivative is represented by a AstrometryTransformLinear, in which (hopefully), the offset terms are zero.

position.

Step is used for numerical derivation.

Derivative should transform a vector of offsets into a vector of offsets.

Reimplemented in lsst::jointcal::AstrometryTransformIdentity, lsst::jointcal::AstrometryTransformPolynomial, and lsst::jointcal::AstrometryTransformLinear.

Definition at line 119 of file AstrometryTransform.cc.

120 {
121 double x = where.x;
122 double y = where.y;
123 double xp0, yp0;
124 apply(x, y, xp0, yp0);
125
126 double xp, yp;
127 apply(x + step, y, xp, yp);
128 derivative.a11() = (xp - xp0) / step;
129 derivative.a21() = (yp - yp0) / step;
130 apply(x, y + step, xp, yp);
131 derivative.a12() = (xp - xp0) / step;
132 derivative.a22() = (yp - yp0) / step;
133 derivative.dx() = 0;
134 derivative.dy() = 0;
135}
int const step
int y
Definition SpanSet.cc:48

◆ fit()

virtual double lsst::jointcal::AstrometryTransform::fit ( StarMatchList const & starMatchList)
pure virtual

◆ getJacobian() [1/2]

double lsst::jointcal::AstrometryTransform::getJacobian ( double x,
double y ) const
virtual

returns the local jacobian.

Definition at line 100 of file AstrometryTransform.cc.

100 {
101 double x2, y2;
102 double eps = x * 0.01;
103 if (eps == 0) eps = 0.01;
104 apply(x, y, x2, y2);
105 double dxdx, dydx;
106 apply(x + eps, y, dxdx, dydx);
107 dxdx -= x2;
108 dydx -= y2;
109 double dxdy, dydy;
110 apply(x, y + eps, dxdy, dydy);
111 dxdy -= x2;
112 dydy -= y2;
113 return ((dxdx * dydy - dxdy * dydx) / (eps * eps));
114}

◆ getJacobian() [2/2]

virtual double lsst::jointcal::AstrometryTransform::getJacobian ( Point const & point) const
inlinevirtual

returns the local jacobian.

Definition at line 110 of file AstrometryTransform.h.

110{ return getJacobian(point.x, point.y); }
virtual double getJacobian(Point const &point) const
returns the local jacobian.

◆ getNpar()

virtual std::size_t lsst::jointcal::AstrometryTransform::getNpar ( ) const
inlinevirtual

◆ getParams()

void lsst::jointcal::AstrometryTransform::getParams ( double * params) const

params should be at least Npar() long

Definition at line 217 of file AstrometryTransform.cc.

217 {
218 std::size_t npar = getNpar();
219 for (std::size_t i = 0; i < npar; ++i) params[i] = paramRef(i);
220}
virtual std::size_t getNpar() const
returns the number of parameters (to compute chi2's)
virtual double paramRef(Eigen::Index i) const

◆ inverseTransform()

std::unique_ptr< AstrometryTransform > lsst::jointcal::AstrometryTransform::inverseTransform ( double precision,
const Frame & region ) const
virtual

returns an inverse transform. Numerical if not overloaded.

precision and region refer to the "input" side of this, and hence to the output side of the returned AstrometryTransform.

Reimplemented in lsst::jointcal::TanPixelToRaDec, lsst::jointcal::TanSipPixelToRaDec, lsst::jointcal::TanRaDecToPixel, lsst::jointcal::AstrometryTransformLinear, and lsst::jointcal::AstrometryTransformInverse.

Definition at line 304 of file AstrometryTransform.cc.

305 {
306 return std::unique_ptr<AstrometryTransform>(new AstrometryTransformInverse(this, precision, region));
307}

◆ linearApproximation()

AstrometryTransformLinear lsst::jointcal::AstrometryTransform::linearApproximation ( Point const & where,
double step = 0.01 ) const
virtual

linear (local) approximation.

Reimplemented in lsst::jointcal::AstrometryTransformIdentity, and lsst::jointcal::AstrometryTransformLinear.

Definition at line 137 of file AstrometryTransform.cc.

138 {
139 Point outwhere = apply(where);
140 AstrometryTransformLinear der;
141 computeDerivative(where, der, step);
142 return AstrometryTransformLinearShift(outwhere.x, outwhere.y) * der *
143 AstrometryTransformLinearShift(-where.x, -where.y);
144}
virtual void computeDerivative(Point const &where, AstrometryTransformLinear &derivative, double step=0.01) const
Computes the local Derivative of a transform, w.r.t.

◆ offsetParams()

void lsst::jointcal::AstrometryTransform::offsetParams ( Eigen::VectorXd const & delta)

Definition at line 222 of file AstrometryTransform.cc.

222 {
223 std::size_t npar = getNpar();
224 for (std::size_t i = 0; i < npar; ++i) paramRef(i) += delta[i];
225}

◆ paramDerivatives()

void lsst::jointcal::AstrometryTransform::paramDerivatives ( Point const & where,
double * dx,
double * dy ) const
virtual

Derivative w.r.t parameters.

Derivatives should be al least 2*NPar long. first Npar, for x, last Npar for y.

Reimplemented in lsst::jointcal::AstrometryTransformPolynomial.

Definition at line 237 of file AstrometryTransform.cc.

237 {
238 throw LSST_EXCEPT(pex::exceptions::InvalidParameterError,
239 "AstrometryTransform::paramDerivatives() should never be called ");
240}
#define LSST_EXCEPT(type,...)
Create an exception with a given type.
Definition Exception.h:48

◆ paramRef() [1/2]

double & lsst::jointcal::AstrometryTransform::paramRef ( Eigen::Index i)
virtual

Reimplemented in lsst::jointcal::AstrometryTransformPolynomial.

Definition at line 232 of file AstrometryTransform.cc.

232 {
233 throw LSST_EXCEPT(pex::exceptions::InvalidParameterError,
234 "AstrometryTransform::paramRef should never be called ");
235}

◆ paramRef() [2/2]

double lsst::jointcal::AstrometryTransform::paramRef ( Eigen::Index i) const
virtual

Reimplemented in lsst::jointcal::AstrometryTransformPolynomial.

Definition at line 227 of file AstrometryTransform.cc.

227 {
228 throw LSST_EXCEPT(pex::exceptions::InvalidParameterError,
229 std::string("AstrometryTransform::paramRef should never be called "));
230}

◆ print()

virtual void lsst::jointcal::AstrometryTransform::print ( std::ostream & out) const
pure virtual

◆ roughInverse()

std::unique_ptr< AstrometryTransform > lsst::jointcal::AstrometryTransform::roughInverse ( const Frame & region) const
virtual

Rough inverse.

Stored by the numerical inverter to guess starting point for the trials. Just here to enable overloading.

Reimplemented in lsst::jointcal::AstrometryTransformInverse, lsst::jointcal::TanPixelToRaDec, and lsst::jointcal::TanRaDecToPixel.

Definition at line 196 of file AstrometryTransform.cc.

196 {
197 // "in" and "out" refer to the inverse direction.
198 Point centerOut = region.getCenter();
199 Point centerIn = apply(centerOut);
200 AstrometryTransformLinear der;
201 computeDerivative(centerOut, der, std::sqrt(region.getArea()) / 5.);
202 der = der.inverted();
203 der = AstrometryTransformLinearShift(centerOut.x, centerOut.y) * der *
204 AstrometryTransformLinearShift(-centerIn.x, -centerIn.y);
205 return std::unique_ptr<AstrometryTransform>(new AstrometryTransformLinear(der));
206}
T sqrt(T... args)

◆ toAstMap()

virtual std::shared_ptr< ast::Mapping > lsst::jointcal::AstrometryTransform::toAstMap ( jointcal::Frame const & domain) const
inlinevirtual

Create an equivalent AST mapping for this transformation, including an analytic inverse if possible.

Parameters
domainThe domain of the transform, to help find an inverse.
Returns
An AST Mapping that represents this transformation.

Reimplemented in lsst::jointcal::AstrometryTransformIdentity, and lsst::jointcal::AstrometryTransformPolynomial.

Definition at line 189 of file AstrometryTransform.h.

189 {
190 throw std::logic_error("toAstMap is not implemented for this class.");
191 }

◆ transformErrors()

void lsst::jointcal::AstrometryTransform::transformErrors ( Point const & where,
const double * vIn,
double * vOut ) const
virtual

transform errors (represented as double[3] in order V(xx),V(yy),Cov(xy))

Definition at line 163 of file AstrometryTransform.cc.

163 {
164 AstrometryTransformLinear der;
165 computeDerivative(where, der, 0.01);
166 double a11 = der.A11();
167 double a22 = der.A22();
168 double a21 = der.A21();
169 double a12 = der.A12();
170
171 /* (a11 a12) (vxx vxy)
172 M = ( ) and V = ( )
173 (a21 a22) (xvy vyy)
174
175 Vxx = Vin[0], vyy = Vin[1], Vxy = Vin[2];
176 we want to compute M*V*tp(M)
177 A lin alg light package would be perfect...
178 */
179 int xx = 0;
180 int yy = 1;
181 int xy = 2;
182 // M*V :
183
184 double b11 = a11 * vIn[xx] + a12 * vIn[xy];
185 double b22 = a21 * vIn[xy] + a22 * vIn[yy];
186 double b12 = a11 * vIn[xy] + a12 * vIn[yy];
187 double b21 = a21 * vIn[xx] + a22 * vIn[xy];
188
189 // (M*V) * tp(M)
190
191 vOut[xx] = b11 * a11 + b12 * a12;
192 vOut[xy] = b11 * a21 + b12 * a22;
193 vOut[yy] = b21 * a21 + b22 * a22;
194}

◆ transformPosAndErrors()

void lsst::jointcal::AstrometryTransform::transformPosAndErrors ( const FatPoint & in,
FatPoint & out ) const
virtual

Reimplemented in lsst::jointcal::TanRaDecToPixel, and lsst::jointcal::AstrometryTransformPolynomial.

Definition at line 146 of file AstrometryTransform.cc.

146 {
147 FatPoint res; // in case in and out are the same address...
148 res = apply(in);
149 AstrometryTransformLinear der;
150 // could save a call here, since Derivative needs the transform of where that we already have
151 // 0.01 may not be a very good idea in all cases. May be we should provide a way of altering that.
152 computeDerivative(in, der, 0.01);
153 double a11 = der.A11();
154 double a22 = der.A22();
155 double a21 = der.A21();
156 double a12 = der.A12();
157 res.vx = a11 * (a11 * in.vx + 2 * a12 * in.vxy) + a12 * a12 * in.vy;
158 res.vy = a21 * a21 * in.vx + a22 * a22 * in.vy + 2. * a21 * a22 * in.vxy;
159 res.vxy = a21 * a11 * in.vx + a22 * a12 * in.vy + (a21 * a12 + a11 * a22) * in.vxy;
160 out = res;
161}

◆ transformStar()

void lsst::jointcal::AstrometryTransform::transformStar ( FatPoint & in) const
inline

Definition at line 107 of file AstrometryTransform.h.

107{ transformPosAndErrors(in, in); }
virtual void transformPosAndErrors(const FatPoint &in, FatPoint &out) const

◆ write() [1/2]

void lsst::jointcal::AstrometryTransform::write ( const std::string & fileName) const

Definition at line 247 of file AstrometryTransform.cc.

247 {
248 ofstream s(fileName.c_str());
249 write(s);
250 bool ok = !s.fail();
251 s.close();
252 if (!ok)
253 throw LSST_EXCEPT(pex::exceptions::InvalidParameterError,
254 "AstrometryTransform::write, something went wrong for file " + fileName);
255}
T c_str(T... args)
void write(const std::string &fileName) const

◆ write() [2/2]

void lsst::jointcal::AstrometryTransform::write ( std::ostream & stream) const
virtual

Reimplemented in lsst::jointcal::AstrometryTransformIdentity, and lsst::jointcal::AstrometryTransformPolynomial.

Definition at line 257 of file AstrometryTransform.cc.

257 {
258 throw LSST_EXCEPT(
259 pex::exceptions::InvalidParameterError,
260 "AstrometryTransform::write(ostream), should never be called. MEans that it is missing in some "
261 "derived class ");
262}

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