lsst::afw::geom::Angle Class Reference

#include <Angle.h>

Public Member Functions
	Angle (double val, AngleUnit units=radians)
	Angle ()
	Angle (Angle const &other)
	operator double () const
double	asAngularUnits (AngleUnit const &units) const
double	asRadians () const
double	asDegrees () const
double	asHours () const
double	asArcminutes () const
double	asArcseconds () const
double	toUnitSphereDistanceSquared () const
void	wrap ()
void	wrapCtr ()
void	wrapNear (Angle const &refAng)
Angle &	operator*= (double const &d)
Angle &	operator*= (int const &d)
Angle &	operator+= (double const &d)
Angle &	operator+= (int const &d)
Angle &	operator-= (double const &d)
Angle &	operator-= (int const &d)
bool	operator== (const Angle &rhs)
bool	operator!= (const Angle &rhs)
bool	operator<= (const Angle &rhs)
bool	operator>= (const Angle &rhs)
bool	operator< (const Angle &rhs)
bool	operator> (const Angle &rhs)

Static Public Member Functions
static Angle	fromUnitSphereDistanceSquared (double d2)

Private Attributes
double	_val

Friends
class	AngleUnit

Detailed Description

A class representing an Angle

Angles may be manipulated like doubles, and automatically converted to doubles, but they may not be constructed from doubles without calling a constructor or multiplying by an AngleUnit

Definition at line 104 of file Angle.h.

Constructor & Destructor Documentation

lsst::afw::geom::Angle::Angle ( double  val, AngleUnit  units = radians  )

inlineexplicit

Construct an Angle with the specified value (interpreted in the given units)

Definition at line 108 of file Angle.h.

: _val(val*units._val) {}

lsst::afw::geom::Angle::Angle ( )

inline

Definition at line 109 of file Angle.h.

: _val(0) {}

lsst::afw::geom::Angle::Angle ( Angle const &  other )

inline

Copy constructor.

Definition at line 111 of file Angle.h.

: _val(other._val) {}

Member Function Documentation

double lsst::afw::geom::Angle::asAngularUnits ( AngleUnit const &  units ) const

inline

Convert an Angle to a float in radians Return an Angle's value as a double in the specified units (i.e. afwGeom::degrees)

Definition at line 118 of file Angle.h.

                                                        {
        return _val/units._val;
    }

double lsst::afw::geom::Angle::asArcminutes ( ) const

inline

Return an Angle's value as a double in arcminutes

Definition at line 128 of file Angle.h.

{ return asAngularUnits(arcminutes); }

double lsst::afw::geom::Angle::asArcseconds ( ) const

inline

Return an Angle's value as a double in arcseconds

Definition at line 130 of file Angle.h.

{ return asAngularUnits(arcseconds); }

double lsst::afw::geom::Angle::asDegrees ( ) const

inline

Return an Angle's value as a double in degrees

Definition at line 124 of file Angle.h.

{ return asAngularUnits(degrees); }

double lsst::afw::geom::Angle::asHours ( ) const

inline

Return an Angle's value as a double in hours

Definition at line 126 of file Angle.h.

{ return asAngularUnits(hours); }

double lsst::afw::geom::Angle::asRadians ( ) const

inline

Return an Angle's value as a double in radians

Definition at line 122 of file Angle.h.

{ return asAngularUnits(radians); }

static Angle lsst::afw::geom::Angle::fromUnitSphereDistanceSquared ( double  d2 )

inlinestatic

Definition at line 134 of file Angle.h.

                                                              {
                return (std::acos(1. - d2/2.)) * radians;
                // == 2.0 * asin(0.5 * sqrt(d2))
        }

lsst::afw::geom::Angle::operator double ( ) const

inline

Convert an Angle to a double in radians

Definition at line 113 of file Angle.h.

{ return _val; }

bool lsst::afw::geom::Angle::operator!= ( const Angle &  rhs )

inline

Definition at line 228 of file Angle.h.

:
    double _val;

Angle& lsst::afw::geom::Angle::operator*= ( double const &  d )

inline

Definition at line 213 of file Angle.h.

{     \

Angle& lsst::afw::geom::Angle::operator*= ( int const &  d )

inline

Definition at line 214 of file Angle.h.

{     \

Angle& lsst::afw::geom::Angle::operator+= ( double const &  d )

inline

Definition at line 215 of file Angle.h.

{     \

Angle& lsst::afw::geom::Angle::operator+= ( int const &  d )

inline

Definition at line 216 of file Angle.h.

{     \

Angle& lsst::afw::geom::Angle::operator-= ( double const &  d )

inline

Definition at line 217 of file Angle.h.

{     \

Angle& lsst::afw::geom::Angle::operator-= ( int const &  d )

inline

Definition at line 218 of file Angle.h.

{     \

bool lsst::afw::geom::Angle::operator< ( const Angle &  rhs )

inline

Definition at line 231 of file Angle.h.

:
    double _val;

bool lsst::afw::geom::Angle::operator<= ( const Angle &  rhs )

inline

Definition at line 229 of file Angle.h.

:
    double _val;

bool lsst::afw::geom::Angle::operator== ( const Angle &  rhs )

inline

Definition at line 227 of file Angle.h.

:
    double _val;

bool lsst::afw::geom::Angle::operator> ( const Angle &  rhs )

inline

Definition at line 232 of file Angle.h.

:
    double _val;

bool lsst::afw::geom::Angle::operator>= ( const Angle &  rhs )

inline

Definition at line 230 of file Angle.h.

:
    double _val;

double lsst::afw::geom::Angle::toUnitSphereDistanceSquared ( ) const

inline

Definition at line 132 of file Angle.h.

{ return 2. * (1. - std::cos(asRadians())); }

void lsst::afw::geom::Angle::wrap ( )

inline

Wraps this angle to the range [0, 2 pi)

Warning

The upper limit is only guaranteed for radians; the upper limit may be slightly squishy for other units, due to roundoff errors. Whether there are any violations is unknown; please update this comment if you can prove that the limits are or are not valid for all supported units.

Definition at line 146 of file Angle.h.

                    {
                _val = std::fmod(_val, TWOPI);
                // _val is now in the range (-TWOPI, TWOPI)
                if (_val < 0.0)
                        _val += TWOPI;
                // if _val is small enough, adding 2 pi gives 2 pi
                if (_val >= TWOPI)
                        _val = 0.0;
        }

void lsst::afw::geom::Angle::wrapCtr ( )

inline

Wrap this angle to the range [-pi, pi)

Warning

Exact limits are only guaranteed for radians; limits for other units may be slightly squishy, due to roundoff errors. Whether there are any violations is unknown; please update this comment if you can prove that the limits are or are not valid for all supported units.

Definition at line 162 of file Angle.h.

                       {
                _val = std::fmod(_val, TWOPI);
                // _val is now in the range [-TWOPI, TWOPI]
        if (_val < -PI) {
            _val += TWOPI;
            if (_val >= PI) {
                // handle roundoff error, however unlikely
                _val = -PI;
            }
        } else if (_val >= PI) {
            _val -= TWOPI;
            if (_val < -PI) {
                // handle roundoff error, however unlikely
                _val = -PI;
            }
        }
        }

void lsst::afw::geom::Angle::wrapNear ( Angle const &  refAng )

inline

Wrap this angle such that pi <= this - refAng < pi

Warning

Exact limits are only guaranteed for radians; limits for other units may be slightly squishy due to roundoff errors. There are known violations that are demonstrated in testWrap in tests/angle.py.

Parameters

refAng

reference angle to match

Definition at line 186 of file Angle.h.

          {
            // compute this = (this - refAng).wrapCtr() + refAng
            // which is correct except for roundoff error at the edges
            double refAngRad = refAng.asRadians();
            *this -= refAng;
            wrapCtr();
        _val += refAngRad;

        // roundoff can cause slightly out-of-range values; fix those
        if (_val - refAngRad >= PI) {
            _val -= TWOPI;
        }
        // maximum relative roundoff error for subtraction is 2 epsilon
        if (_val - refAngRad < -PI) {
            _val -= _val * 2.0 * std::numeric_limits<double>::epsilon();
        }
        }

Friends And Related Function Documentation

friend class AngleUnit

friend

Definition at line 105 of file Angle.h.

Member Data Documentation

double lsst::afw::geom::Angle::_val

private

Definition at line 237 of file Angle.h.

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

• /lsst/home/lsstsw/stack/Linux64/afw/master-gae20e2b580+3/include/lsst/afw/geom/Angle.h