Fit2D.h

Classes

Fit2D -- Fit 2-D objects to 2-D Lattices or Arrays (full description)

class Fit2D

Types

enum Types

GAUSSIAN = 0

DISK = 1

LEVEL = 2

nTypes

enum ErrorTypes

OK = 0
ok

NOCONVERGE = 1
Did not converge

FAILED = 2
Solution failed

NOGOOD = 3
There were no unmasked points

NOMODELS = 4
No models set

nErrorTypes
Number of conditions

Interface

Public Members

explicit Fit2D(LogIO& logger)

~Fit2D()

Fit2D(const Fit2D& other)

Fit2D& operator=(const Fit2D& other)

uInt addModel (Fit2D::Types type, const Vector<Double>& parameters, const Vector<Bool>& parameterMask)

uInt addModel(Fit2D::Types type, const Vector<Double>& parameters)

static Vector<Bool> convertMask (const String fixedmask, Fit2D::Types type)

void setIncludeRange (Double minVal, Double maxVal)

void setExcludeRange (Double minVal, Double maxVal)

void resetRange()

static uInt nParameters (Fit2D::Types type)

uInt nModels() const

Vector<Double> estimate(Fit2D::Types type, const MaskedLattice<Float>& data)

Vector<Double> estimate(Fit2D::Types type, const Lattice<Float>& data)

Vector<Double> estimate(Fit2D::Types type, const Array<Float>& data)

Vector<Double> estimate(Fit2D::Types type, const Array<Float>& data, const Array<Bool>& mask)

Fit2D::ErrorTypes fit(const MaskedLattice<Float>& data, const Lattice<Float>& sigma)

Fit2D::ErrorTypes fit(const Lattice<Float>& data, const Lattice<Float>& sigma)

Fit2D::ErrorTypes fit(const Array<Float>& data, const Array<Float>& sigma)

Fit2D::ErrorTypes fit(const Array<Float>& data, const Array<Bool>& mask, const Array<Float>& sigma)

Fit2D::ErrorTypes residual(Array<Float>& resid, const Array<Float>& data)

Fit2D::ErrorTypes residual(Array<Float>& resid, const MaskedLattice<Float>& data)

Fit2D::ErrorTypes residual(Array<Float>& resid, const Lattice<Float>& data)

String errorMessage () const

Vector<Double> availableSolution () const

Vector<Double> availableSolution (uInt which) const

Vector<Double> availableErrors() const

Vector<Double> availableErrors(uInt which) const

uInt numberIterations() const

Double chiSquared () const

uInt numberPoints () const

static String type(Fit2D::Types type)

static Fit2D::Types type(const String& type)

Fit2D::Types type(uInt which)

static Double paToGauss2D (Double pa)

static Double paFromGauss2D (Double pa)

Private Members

Fit2D::ErrorTypes fitData(const Vector<Double>& values, const Matrix<Double>& pos, const Vector<Double>& sigma)

Vector<Double> availableSolution (uInt& iStart, uInt which) const

Vector<Double> availableErrors (uInt& iStart, uInt which) const

Vector<Double> getParams(uInt which) const

void setParams(const Vector<Double>& params, uInt which)

Bool includeIt (Float value, const Vector<Float>& range, Int includeIt) const

Bool selectData (Matrix<Double>& pos, Vector<Double>& values, Vector<Double>& weights, const Array<Float>& pixels, const Array<Bool>& mask, const Array<Float>& sigma)

void piRange (Double& pa) const

Description

Prerequisite

Synopsis

This class allows you to fit different types of 2-D models to either Lattices or Arrays. These must be 2 dimensional; for Lattices, the appropriate 2-D Lattice can be made with the SubLattice class.

You may fit more than one model simultaneously to the data. Models are added with the addModel method. With this method, you also specify the initial guesses of the parameters of the model. Any parameters involving coordinates are expected in zero-relative absolute pixel coordinates (e.g. the centre of a model). Additionally with the addModel method, you may specify which parameters are to be held fixed during the fitting process. This is done with the parameterMask Vector which is in the same order as the parameter Vector. A value of True indicates the parameter will be fitted for. Presently, when you say fix the minor axis, you really end up fixing the axial ratio (internals). I don't have a solution for this presently.

For Gaussians, the parameter Vector (input or output) consists, in order, of the peak, x location, y location, FWHM of major axis, FWHM of minor axis, and position angle of the major axis (in radians). The position angle is positive +x to +y in the pixel coordinate system ([0,0] in center of image) and in the range -2pi to 2pi. When the solution is recovered, the position angle will be in the range 0 to pi.

Example

To Do

template it
Speed up some Array calculations indexed with IPositions
Don't handle Lattices simply by getting pixels into Arrays
make an addModel interface taking functionals

Member Description

enum Types

Enum describing the different models you can fit

enum ErrorTypes

Enum describing output error conditions

explicit Fit2D(LogIO& logger)

Constructor

~Fit2D()

Destructor

Fit2D(const Fit2D& other)

Copy constructor. Uses copy semantics except for the logger for which a reference copy is made

Fit2D& operator=(const Fit2D& other)

Assignment operator. Uses copy semantics except for the logger for which a reference copy is made

uInt addModel (Fit2D::Types type, const Vector<Double>& parameters, const Vector<Bool>& parameterMask)
uInt addModel(Fit2D::Types type, const Vector<Double>& parameters)

Add a model to the list to be simultaneously fit and return its index. Specify the initial guesses for the model and a mask indicating whether the parameter is fixed (False) during the fit or not. Returns the the model number added (0, 1, 2 etc)

static Vector<Bool> convertMask (const String fixedmask, Fit2D::Types type)

Convert mask from a string to a vector. The string gives the parameters to keep fixed in the fit (f (flux), x (x position), y (y position), a (FWHM major axis), b (FWHM minor axis), p (position angle)

void setIncludeRange (Double minVal, Double maxVal)
void setExcludeRange (Double minVal, Double maxVal)
void resetRange()

Set a pixel selection range. When the fit is done, only pixels in the specified range are included/excluded. Only the last call of either of these will be active.

static uInt nParameters (Fit2D::Types type)

Return number of parameters for this type of model

uInt nModels() const

Recover number of models

Vector<Double> estimate(Fit2D::Types type, const MaskedLattice<Float>& data)
Vector<Double> estimate(Fit2D::Types type, const Lattice<Float>& data)
Vector<Double> estimate(Fit2D::Types type, const Array<Float>& data)
Vector<Double> estimate(Fit2D::Types type, const Array<Float>& data, const Array<Bool>& mask)

Determine an initial estimate for the solution of the specified model type to the given data - no compound models are allowable in this function. If you have specified an include or exclude pixel range to the fitter, that will be honoured. This function does not interact with the addModel function. Returns a zero length vector if it fails to make an estimate.

Fit2D::ErrorTypes fit(const MaskedLattice<Float>& data, const Lattice<Float>& sigma)
Fit2D::ErrorTypes fit(const Lattice<Float>& data, const Lattice<Float>& sigma)
Fit2D::ErrorTypes fit(const Array<Float>& data, const Array<Float>& sigma)
Fit2D::ErrorTypes fit(const Array<Float>& data, const Array<Bool>& mask, const Array<Float>& sigma)

Do the fit. Returns an enum value to tell you what happened if the fit failed for some reasons. A message can also be found with function errorMessage if the fit was not successful. For Array(i,j) i is x and j is y

Fit2D::ErrorTypes residual(Array<Float>& resid, const Array<Float>& data)
Fit2D::ErrorTypes residual(Array<Float>& resid, const MaskedLattice<Float>& data)
Fit2D::ErrorTypes residual(Array<Float>& resid, const Lattice<Float>& data)

Find the residuals to the fit.

String errorMessage () const

If function fit failed, you will find a message here saying why it failed

Vector<Double> availableSolution () const
Vector<Double> availableSolution (uInt which) const

Recover solution for either all model components or a specific one. These functions will return an empty vector if there is no valid solution. All available parameters (fixed and adjustable) are included in the solution vectors.

Vector<Double> availableErrors() const
Vector<Double> availableErrors(uInt which) const

The errors. All available parameters (fixed and adjustable) are included in the error vectors. Unsolved for parameters will have error 0.

uInt numberIterations() const

The number of iterations that the fitter finished with

Double chiSquared () const

The chi squared of the fit. Returns 0 if fit has been done.

uInt numberPoints () const

The number of points used for the last fit

static String type(Fit2D::Types type)

Return type as a string

static Fit2D::Types type(const String& type)

Return string type as enum (min match)

Fit2D::Types type(uInt which)

Find type of specific model

static Double paToGauss2D (Double pa)

Convert p.a. (radians) from positive +x -> +y (Fit2D) to positive +y -> -x (Gaussian2D)

static Double paFromGauss2D (Double pa)

Convert p.a. (radians) from positive +y -> -x (Gaussian2D) to positive +x -> +y (Fit2D)

Fit2D::ErrorTypes fitData(const Vector<Double>& values, const Matrix<Double>& pos, const Vector<Double>& sigma)

Vector<Double> availableSolution (uInt& iStart, uInt which) const
Vector<Double> availableErrors (uInt& iStart, uInt which) const

Returns available (adjustable + fixed) solution for model of interest and tells you where it began in the full solution vector Does no axial ratio nor position angle conversions from direct fit solution vector

Vector<Double> getParams(uInt which) const

void setParams(const Vector<Double>& params, uInt which)

Bool includeIt (Float value, const Vector<Float>& range, Int includeIt) const

Bool selectData (Matrix<Double>& pos, Vector<Double>& values, Vector<Double>& weights, const Array<Float>& pixels, const Array<Bool>& mask, const Array<Float>& sigma)