lsst::geom::polynomials::Scaling1d Class Reference

A 1-d affine transform that can be used to map one interval to another. More...

#include <Scaling1d.h>

Public Member Functions
	Scaling1d (double scale, double shift) noexcept
	Construct from the given multiplicative scale and additive shift. More...
	Scaling1d (Scaling1d const &) noexcept=default
	Default copy constructor. More...
	Scaling1d (Scaling1d &&) noexcept=default
	Default move constructor. More...
Scaling1d &	operator= (Scaling1d const &) noexcept=default
	Default copy assignment. More...
Scaling1d &	operator= (Scaling1d &&) noexcept=default
	Default move assignment. More...
double	applyForward (double x) const noexcept
	Apply the transform in the forward direction. More...
double	applyInverse (double y) const noexcept
	Apply the inverse of the forward transform;. More...
double	getScale () const noexcept
	Return the multiplicative scaling. More...
double	getShift () const noexcept
	Return the additive shift. More...
Scaling1d	inverted () const noexcept
	Invert the transform. More...
Scaling1d	then (Scaling1d const &second) const noexcept
	Compose two transforms. More...

Detailed Description

A 1-d affine transform that can be used to map one interval to another.

The transform is represented as an additive shift followed by a multiplicative scaling.

Note

This class (and especially its 2-d counterpart, Scaling2d) has a lot in common with geom::AffineTransform, and ideally they should share code and be highly interoperable. Doing that well would require a larger-scale rethink of geom, however, and at present we don't actually have a use case for that interoperability, so it's something we should keep in mind for the future, not a high priority for the present.

Exception Safety

All operations on Scaling1d are noexcept.

See also

makeUnitRangeScaling1d

Definition at line 46 of file Scaling1d.h.

Constructor & Destructor Documentation

Scaling1d() [1/3]

lsst::geom::polynomials::Scaling1d::Scaling1d ( double  scale, double  shift  )

inlinenoexcept

Construct from the given multiplicative scale and additive shift.

Definition at line 50 of file Scaling1d.h.

                                                  :
        _scale(scale),
        _shift(shift)
    {}

Scaling1d() [2/3]

lsst::geom::polynomials::Scaling1d::Scaling1d ( Scaling1d const &  )

defaultnoexcept

Default copy constructor.

Scaling1d() [3/3]

lsst::geom::polynomials::Scaling1d::Scaling1d ( Scaling1d &&  )

defaultnoexcept

Default move constructor.

Member Function Documentation

applyForward()

double lsst::geom::polynomials::Scaling1d::applyForward ( double  x ) const

inlinenoexcept

Apply the transform in the forward direction.

Result is defined to be (x + getShift()) * getScale().

Definition at line 72 of file Scaling1d.h.

                                                 {
        return (x + getShift())*getScale();
    }

applyInverse()

double lsst::geom::polynomials::Scaling1d::applyInverse ( double  y ) const

inlinenoexcept

Apply the inverse of the forward transform;.

Definition at line 79 of file Scaling1d.h.

                                                 {
        return y/_scale - _shift;
    }

getScale()

double lsst::geom::polynomials::Scaling1d::getScale ( ) const

inlinenoexcept

Return the multiplicative scaling.

Definition at line 84 of file Scaling1d.h.

{ return _scale; }

getShift()

double lsst::geom::polynomials::Scaling1d::getShift ( ) const

inlinenoexcept

Return the additive shift.

Definition at line 87 of file Scaling1d.h.

{ return _shift; }

inverted()

Scaling1d lsst::geom::polynomials::Scaling1d::inverted ( ) const

inlinenoexcept

Invert the transform.

If r = t.inverted(), then r.applyForward(x) is equivalent to t.applyInverse(x) and r.applyInverse(y) is equivalent to t.applyForward(y).

Definition at line 96 of file Scaling1d.h.

                                        {
        return Scaling1d(1.0/_scale, -_shift*_scale);
    }

operator=() [1/2]

Scaling1d& lsst::geom::polynomials::Scaling1d::operator= ( Scaling1d &&  )

defaultnoexcept

Default move assignment.

operator=() [2/2]

Scaling1d& lsst::geom::polynomials::Scaling1d::operator= ( Scaling1d const &  )

defaultnoexcept

Default copy assignment.

then()

Scaling1d lsst::geom::polynomials::Scaling1d::then ( Scaling1d const &  second ) const

inlinenoexcept

Compose two transforms.

If r = a.then(b), then r.applyForward(x) is equivalent to b.applyForward(a.applyForward(x)) and r.applyInverse(y) is equivalent to a.applyInverse(b.applyInverse(y)).

Definition at line 107 of file Scaling1d.h.

                                                            {
        return Scaling1d(getScale()*second.getScale(),
                                 getShift() + second.getShift()/getScale());
    }

---

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

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-0.7.0/Linux64/geom/22.0.1-6-g8d3140d+720564cf76/include/lsst/geom/polynomials/Scaling1d.h