Map from a spherical system to a cartesian system using standard FITS sky coordinate projections. More...

#include <WcsMap.h>

Inheritance diagram for ast::WcsMap:

Public Types
using	ObjectPtr = std::unique_ptr<AstObject, Deleter>
	unique pointer holding an AST raw pointer

Public Member Functions
	WcsMap (int ncoord, WcsType type, int lonax, int latax, std::string const &options="")
	Create a WcsMap.

virtual	~WcsMap ()

	WcsMap (WcsMap const &)=default
	Copy constructor: make a deep copy.

	WcsMap (WcsMap &&)=default

WcsMap &	operator= (WcsMap const &)=delete

WcsMap &	operator= (WcsMap &&)=default

std::shared_ptr< WcsMap >	copy () const
	Return a deep copy of this object.

double	getNatLat () const
	get NatLat: native latitude of the reference point of a FITS-WCS projection.

double	getNatLon () const
	get NatLon: native longitude of the reference point of a FITS-WCS projection.

double	getPVi_m (int i, int m) const
	Get PVi_m for one value of i and m: a FITS-WCS projection parameter.

int	getPVMax (int axis) const
	Get PVMax(axis) for one axis: maximum number of FITS-WCS projection parameters.

std::pair< int, int >	getWcsAxis () const
	Get WcsAxis(lonlat) FITS-WCS projection axis for longitude, latitude.

WcsType	getWcsType () const
	Get WcsType: FITS-WCS projection type.

int	getNIn () const
	Get NIn: the number of input axes.

int	getNOut () const
	Get NOut: the number of output axes.

bool	getIsSimple () const
	Get IsSimple: has the mapping been simplified?

bool	isInverted () const
	Is this an inverted mapping?

bool	getIsLinear () const
	Get IsLinear: is the Mapping linear?

bool	getReport () const
	Get Report: report transformed coordinates to stdout?

bool	hasForward () const
	Is the forward transform available?

bool	hasInverse () const
	Is the inverse transform available?

std::shared_ptr< Mapping >	inverted () const
	Get an inverse mapping.

Array2D	linearApprox (PointD const &lbnd, PointD const &ubnd, double tol) const
	Compute a linear approximation to the forward transformation.

SeriesMap	then (Mapping const &next) const
	Return a series compound mapping this(first(input)) containing shallow copies of the original.

ParallelMap	under (Mapping const &next) const
	Return a parallel compound mapping containing shallow copies of the original.

double	rate (PointD const &at, int ax1, int ax2) const
	Evaluate the rate of change of the Mapping with respect to a specified input, at a specified position.

void	setReport (bool report)
	Set Report: report transformed coordinates to stdout?

std::shared_ptr< Mapping >	simplified () const
	Return a simplied version of the mapping (which may be a compound Mapping such as a CmpMap).

void	applyForward (ConstArray2D const &from, Array2D const &to) const
	Perform a forward transformation on 2-D array, putting the results into a pre-allocated 2-D array.

Array2D	applyForward (ConstArray2D const &from) const
	Perform a forward transformation on a 2-D array, returning the results as a new array.

std::vector< double >	applyForward (std::vector< double > const &from) const
	Perform a forward transformation on a vector, returning the results as a new vector.

void	applyInverse (ConstArray2D const &from, Array2D const &to) const
	Perform an inverse transformation on a 2-D array, putting the results into a pre-allocated 2-D array.

Array2D	applyInverse (ConstArray2D const &from) const
	Perform an inverse transformation on a 2-D array, returning the results as a new 2-D array.

std::vector< double >	applyInverse (std::vector< double > const &from) const
	Perform an inverse transformation on a vector, returning the results as a new vector.

void	tranGridForward (PointI const &lbnd, PointI const &ubnd, double tol, int maxpix, Array2D const &to) const
	Transform a grid of points in the forward direction.

Array2D	tranGridForward (PointI const &lbnd, PointI const &ubnd, double tol, int maxpix, int nPts) const
	Transform a grid of points in the inverse direction, returning the results as a new Array2D.

void	tranGridInverse (PointI const &lbnd, PointI const &ubnd, double tol, int maxpix, Array2D const &to) const
	Transform a grid of points in the inverse direction.

Array2D	tranGridInverse (PointI const &lbnd, PointI const &ubnd, double tol, int maxpix, int nPts) const
	Transform a grid of points in the inverse direction.

bool	operator== (Object const &rhs) const
	Return True if this and `rhs` are the equal.

bool	operator!= (Object const &rhs) const
	Return True if this and `rhs` are not equal.

void	clear (std::string const &attrib)
	Clear the values of a specified set of attributes for an Object.

bool	hasAttribute (std::string const &attrib) const
	Does this object have an attribute with the specified name?

std::string	getClassName () const
	Get Class: the name of the class (e.g.

std::string	getID () const
	Get ID: object identification string that is not copied.

std::string	getIdent () const
	Get Ident: object identification string that is copied.

int	getNObject () const
	Get NObject: number of AST objects in existence of the same type as the underlying AST class.

int	getObjSize () const
	Get ObjSize: the in-memory size of the AST object in bytes.

int	getRefCount () const
	Get RefCount: number of active pointers to the underlying AST object.

bool	getUseDefs () const
	Get UseDefs: allow use of default values for Object attributes?

void	lock (bool wait)
	Lock this object for exclusive use by the calling thread.

bool	same (Object const &other) const
	Does this contain the same AST object as another?

void	setID (std::string const &id)
	Set ID: object identification string that is not copied.

void	setIdent (std::string const &ident)
	Set Ident: object identification string that is copied.

void	setUseDefs (bool usedefs)
	Set UseDefs: allow use of default values for Object attributes?

void	show (std::ostream &os, bool showComments=true) const
	Print a textual description the object to an ostream.

std::string	show (bool showComments=true) const
	Return a textual description the object as a string.

bool	test (std::string const &attrib) const
	Has this attribute been explicitly set (and not subsequently cleared)?

void	unlock (bool report=false)
	Unlock this object previously locked using lock, so that other threads can use this object.


AstObject const *	getRawPtr () const
	Get the raw AST pointer.

AstObject *	getRawPtr ()
	Get the raw AST pointer.

Static Public Member Functions
static std::shared_ptr< Object >	fromString (std::string const &str)
	Construct an Object from a string, using astFromString.

template<typename Class >
static std::shared_ptr< Class >	fromAstObject (AstObject *rawObj, bool copy)
	Given a bare AST object pointer return a shared pointer to an ast::Object of the correct type.

Protected Member Functions
virtual std::shared_ptr< Object >	copyPolymorphic () const override
	Return a deep copy of this object.

	WcsMap (AstWcsMap *rawptr)
	Construct a WcsMap from a raw AST pointer.

template<typename Class >
std::shared_ptr< Class >	decompose (int i, bool copy) const
	Return a deep copy of one of the two component mappings.

template<typename T , typename AstT >
std::shared_ptr< T >	copyImpl () const
	Implementation of deep copy.

bool	getB (std::string const &attrib) const
	Get the value of an attribute as a bool.

std::string const	getC (std::string const &attrib) const
	Get the value of an attribute as a string.

double	getD (std::string const &attrib) const
	Get the value of an attribute as a double.

float	getF (std::string const &attrib) const
	Get the value of an attribute as a float.

int	getI (std::string const &attrib) const
	Get the value of an attribute as an int.

long int	getL (std::string const &attrib) const
	Get the value of an attribute as a long int.

void	set (std::string const &setting)
	Assign a set of attribute values, over-riding any previous values.

void	setB (std::string const &attrib, bool value)
	Set the value of an attribute as a bool.

void	setC (std::string const &attrib, std::string const &value)
	Set the value of an attribute as a string.

void	setD (std::string const &attrib, double value)
	Set the value of an attribute as a double.

void	setF (std::string const &attrib, float value)
	Set the value of an attribute as a float.

void	setI (std::string const &attrib, int value)
	Set the value of an attribute as an int.

void	setL (std::string const &attrib, long int value)
	Set the value of an attribute as a long int.

Static Protected Member Functions
template<typename ShimT , typename AstT >
static std::shared_ptr< ShimT >	makeShim (AstObject *p)
	Functor to make an astshim instance from a raw AST pointer of the corresponding type.

Friends
class	Object

Detailed Description

Map from a spherical system to a cartesian system using standard FITS sky coordinate projections.

WcsMap is used to represent sky coordinate projections as described in the FITS world coordinate system (FITS-WCS) paper II "Representations of Celestial Coordinates in FITS" by M. Calabretta and E.W. Griesen. This paper defines a set of functions, or sky projections, which transform longitude-latitude pairs representing spherical celestial coordinates into corresponding pairs of Cartesian coordinates (and vice versa).

A WcsMap is a specialised form of Mapping which implements these sky projections and applies them to a specified pair of coordinates. All the projections in the FITS-WCS paper are supported, plus the now deprecated "TAN with polynomial correction terms" projection which is refered to here by the code "TPN". Using the FITS-WCS terminology, the transformation is between "native spherical" and "projection plane" coordinates (also called "intermediate world coordinates". These coordinates may, optionally, be embedded in a space with more than two dimensions, the remaining coordinates being copied unchanged. Note, however, that for consistency with other AST facilities, a WcsMap handles coordinates that represent angles in radians (rather than the degrees used by FITS-WCS).

The type of FITS-WCS projection to be used and the coordinates (axes) to which it applies are specified when a WcsMap is first created. The projection type may subsequently be determined using the WcsType attribute and the coordinates on which it acts may be determined using the WcsAxis(lonlat) attribute.

Each WcsMap also allows up to 100 "projection parameters" to be associated with each axis. These specify the precise form of the projection, and are accessed using PVi_m attribute, where "i" is the integer axis index (starting at 1), and "m" is an integer "parameter index" in the range 0 to 99. The number of projection parameters required by each projection, and their meanings, are dependent upon the projection type (most projections either do not use any projection parameters, or use parameters 1 and 2 associated with the latitude axis). Before creating a WcsMap you should consult the FITS-WCS paper for details of which projection parameters are required, and which have defaults. When creating the WcsMap, you must explicitly set values for all those required projection parameters which do not have defaults defined in this paper.

Attributes

NatLat: native latitude of the reference point of a FITS-WCS projection.
NatLon: native longitude of the reference point of a FITS-WCS projection.
PVi_m: FITS-WCS projection parameters.
PVMax: maximum number of FITS-WCS projection parameters.
WcsAxis(lonlat): FITS-WCS projection axes.
WcsType: FITS-WCS projection type.

Notes

The forward transformation of a WcsMap converts between FITS-WCS "native spherical" and "relative physical" coordinates, while the inverse transformation converts in the opposite direction.
If any set of coordinates cannot be transformed (for example, many projections do not cover the entire celestial sphere), then a WcsMap will yield coordinate values of nan.

Definition at line 146 of file WcsMap.h.

Member Typedef Documentation

◆ ObjectPtr

using ast::Object::ObjectPtr = std::unique_ptr<AstObject, Deleter>

inherited

unique pointer holding an AST raw pointer

Definition at line 59 of file Object.h.

Constructor & Destructor Documentation

◆ WcsMap() [1/4]

ast::WcsMap::WcsMap	(	int	ncoord,
		WcsType	type,
		int	lonax,
		int	latax,
		std::string const &	options = "" )

inlineexplicit

Create a WcsMap.

Parameters

[in]	ncoord	The number of coordinate values for each point to be transformed (i.e. the number of dimensions of the space in which the points will reside). This must be at least 2. The same number is applicable to both input and output points.
[in]	type	The type of FITS-WCS projection to apply, as a WcsType enum such as WcsType::TAN (for a tangent plane projection). The enum constant name give the projection type code (in upper case) as used in the FITS-WCS "CTYPEi" keyword. You should consult the FITS-WCS paper for a list of the available projections. The additional code of WcsType::TPN can be supplied which represents a TAN projection with polynomial correction terms as defined in an early draft of the FITS-WCS paper.
[in]	lonax	Index of the longitude axis. This should lie in the range 1 to `ncoord`.
[in]	latax	Index of the latitude axis. This should lie in the range 1 to `ncoord`.
[in]	options	Pointer to a null-terminated string containing an optional comma-separated list of attribute assignments to be used for initialising the new WcsMap. The syntax used is identical to that for the astSet function and may include "printf" format specifiers identified by "%" symbols in the normal way. If the sky projection to be implemented requires projection parameter values to be set, then this should normally be done here via the PVi_m attribute (see the "Examples" section). Setting values for these parameters is mandatory if they do not have default values (as defined in the FITS-WCS paper).

Warning: The validity of any projection parameters given via the PVi_m PVi_m parameter in the "options" string is not checked at construction. However, their validity is checked when the resulting WcsMap is used to transform coordinates, and an error will result if the projection parameters do not satisfy all the required constraints (as defined in the FITS-WCS paper).

Examples

auto wcsmap = ast::WcsMap(2, WcsType::MER, 1, 2, "")

Create a WcsMap that implements a FITS-WCS Mercator projection on pairs of coordinates, with coordinates 1 and 2 representing the longitude and latitude respectively. Note that the FITS-WCS Mercator projection does not require any projection parameters.
auto wcsmap = ast::WcsMap(3, WcsType::COE, 2, 3, "PV3_1=40.0")

Create a WcsMap that implements a FITS-WCS conical equal area projection. The WcsMap acts on points in a 3-dimensional space; coordinates 2 and 3 represent longitude and latitude respectively, while the values of coordinate 1 are copied unchanged. Projection parameter 1 associatyed with the latitude axis (corresponding to FITS keyword "PV3_1") is required and has no default, so is set explicitly to 40.0 degrees. Projection parameter 2 (corresponding to FITS keyword "PV3_2") is required but has a default of zero, so need not be specified.

Definition at line 209 of file WcsMap.h.

            : Mapping(reinterpret_cast<AstMapping *>(
                      astWcsMap(ncoord, static_cast<int>(type), lonax, latax, "%s", options.c_str()))) {
        assertOK();
    }

◆ ~WcsMap()

virtual ast::WcsMap::~WcsMap ( )

inlinevirtual

Definition at line 215 of file WcsMap.h.

215{}

◆ WcsMap() [2/4]

ast::WcsMap::WcsMap ( WcsMap const & )

default

Copy constructor: make a deep copy.

◆ WcsMap() [3/4]

ast::WcsMap::WcsMap ( WcsMap && )

default

◆ WcsMap() [4/4]

ast::WcsMap::WcsMap ( AstWcsMap * rawptr )

inlineexplicitprotected

Construct a WcsMap from a raw AST pointer.

Definition at line 264 of file WcsMap.h.

                                       : Mapping(reinterpret_cast<AstMapping *>(rawptr)) {
        if (!astIsAWcsMap(getRawPtr())) {
            std::ostringstream os;
            os << "this is a " << getClassName() << ", which is not a WcsMap";
            throw std::invalid_argument(os.str());
        }
    }

Member Function Documentation

◆ applyForward() [1/3]

Array2D ast::Mapping::applyForward ( ConstArray2D const & from ) const

inlineinherited

Perform a forward transformation on a 2-D array, returning the results as a new array.

Parameters

[in] from input coordinates, with dimensions (nPts, nIn)

Returns: the results as a new array with dimensions (nPts, nOut)

Definition at line 268 of file Mapping.h.

                                                         {
        Array2D to = ndarray::allocate(getNOut(), from.getSize<1>());
        _tran(from, true, to);
        return to;
    }

◆ applyForward() [2/3]

void ast::Mapping::applyForward	(	ConstArray2D const &	from,
		Array2D const &	to ) const

inlineinherited

Perform a forward transformation on 2-D array, putting the results into a pre-allocated 2-D array.

Parameters

[in]	from	input coordinates, with dimensions (nPts, nIn)
[out]	to	transformed coordinates, with dimensions (nPts, nOut)

Definition at line 260 of file Mapping.h.

260{ _tran(from, true, to); }

◆ applyForward() [3/3]

std::vector< double > ast::Mapping::applyForward ( std::vector< double > const & from ) const

inlineinherited

Perform a forward transformation on a vector, returning the results as a new vector.

Parameters

[in] from input coordinates as a vector, with axes adjacent, e.g. x0, y0, x1, y1...xn, yn

Returns: the results as a new vector

Definition at line 280 of file Mapping.h.

                                                                        {
        auto fromArr = arrayFromVector(from, getNIn());
        std::vector<double> to(fromArr.getSize<1>() * getNOut());
        auto toArr = arrayFromVector(to, getNOut());
        _tran(fromArr, true, toArr);
        return to;
    }

◆ applyInverse() [1/3]

Array2D ast::Mapping::applyInverse ( ConstArray2D const & from ) const

inlineinherited

Perform an inverse transformation on a 2-D array, returning the results as a new 2-D array.

Parameters

[in] from output coordinates, with dimensions (nPts, nOut)

Returns: the results as a new array with dimensions (nPts, nIn)

Definition at line 302 of file Mapping.h.

                                                         {
        Array2D to = ndarray::allocate(getNIn(), from.getSize<1>());
        _tran(from, false, to);
        return to;
    }

◆ applyInverse() [2/3]

void ast::Mapping::applyInverse	(	ConstArray2D const &	from,
		Array2D const &	to ) const

inlineinherited

Perform an inverse transformation on a 2-D array, putting the results into a pre-allocated 2-D array.

Parameters

[in]	from	input coordinates, with dimensions (nPts, nOut)
[out]	to	transformed coordinates, with dimensions (nPts, nIn)

Definition at line 294 of file Mapping.h.

294{ _tran(from, false, to); }

◆ applyInverse() [3/3]

std::vector< double > ast::Mapping::applyInverse ( std::vector< double > const & from ) const

inlineinherited

Perform an inverse transformation on a vector, returning the results as a new vector.

Parameters

[in] from input coordinates as a vector, with axes adjacent, e.g. x0, y0, x1, y1...xn, yn

Returns: the results as a new vector

Definition at line 314 of file Mapping.h.

                                                                        {
        auto fromArr = arrayFromVector(from, getNOut());
        std::vector<double> to(fromArr.getSize<1>() * getNIn());
        auto toArr = arrayFromVector(to, getNIn());
        _tran(fromArr, false, toArr);
        return to;
    }

◆ clear()

void ast::Object::clear ( std::string const & attrib )

inlineinherited

Clear the values of a specified set of attributes for an Object.

Clearing an attribute cancels any value that has previously been explicitly set for it, so that the standard default attribute value will subsequently be used instead. This also causes the astTest function to return the value zero for the attribute, indicating that no value has been set.

Definition at line 119 of file Object.h.

                                        {
        astClear(getRawPtr(), attrib.c_str());
        assertOK();
    }

◆ copy()

std::shared_ptr< WcsMap > ast::WcsMap::copy ( ) const

inline

Return a deep copy of this object.

Definition at line 224 of file WcsMap.h.

224{ return std::static_pointer_cast<WcsMap>(copyPolymorphic()); }

ast::WcsMap::copyPolymorphic

virtual std::shared_ptr< Object > copyPolymorphic() const override

Return a deep copy of this object.

Definition WcsMap.h:259

◆ copyImpl()

template<typename T , typename AstT >

std::shared_ptr< T > ast::Object::copyImpl ( ) const

inlineprotectedinherited

Implementation of deep copy.

Should be called to implement copyPolymorphic by all derived classes.

Definition at line 320 of file Object.h.

                                      {
        auto *rawptr = reinterpret_cast<AstT *>(astCopy(getRawPtr()));
        auto retptr = std::shared_ptr<T>(new T(rawptr));
        assertOK();
        return retptr;
    }

◆ copyPolymorphic()

virtual std::shared_ptr< Object > ast::WcsMap::copyPolymorphic ( ) const

inlineoverrideprotectedvirtual

Return a deep copy of this object.

This is called by copy.

Each subclass must override this method. The standard implementation is:

return copyImpl<astshim_class, ast_class>();

for example Frame implements this as:

return copyImpl<Frame, AstFrame>();

Reimplemented from ast::Mapping.

Definition at line 259 of file WcsMap.h.

                                                                   {
        return copyImpl<WcsMap, AstWcsMap>();
    }

◆ decompose()

template<typename Class >

template std::shared_ptr< Mapping > ast::Mapping::decompose	(	int	i,
		bool	copy ) const

protectedinherited

Return a deep copy of one of the two component mappings.

This is intended to be exposed by classes that need it (e.g. CmpMap, CmpFrame and TranMap) as operator[].

Template Parameters

Class astshim class of returned object, typically Mapping or Frame.

Parameters

[in]	i	Index: 0 for the first mapping, 1 for the second
[in]	copy	If true make a deep copy, else a shallow copy

Exceptions

std::invalid_argument	if `i` is not 0 or 1.
std::runtime_error	if this mapping is not a compound mapping.

Definition at line 64 of file Mapping.cc.

                                                              {
    if ((i < 0) || (i > 1)) {
        std::ostringstream os;
        os << "i =" << i << "; must be 0 or 1";
        throw std::invalid_argument(os.str());
    }
    // Report pre-existing problems now so our later test for "not a compound object" is accurate
    assertOK();
 
    AstMapping *rawMap1;
    AstMapping *rawMap2;
    int series, invert1, invert2;
    astDecompose(getRawPtr(), &rawMap1, &rawMap2, &series, &invert1, &invert2);
    assertOK();
 
    if (!rawMap2) {
        // Not a compound object; free rawMap1 (rawMap2 is null, so no need to free it) and throw an exception
        astAnnul(reinterpret_cast<AstObject *>(rawMap1));
        std::ostringstream os;
        os << "This " << getClassName() << " is not a compound object";
        throw std::runtime_error(os.str());
    }
 
    // Make a deep copy of the returned object and free the shallow copies
    AstMapping *retRawMap;
    int invert;
    if (i == 0) {
        retRawMap = reinterpret_cast<AstMapping *>(astCopy(reinterpret_cast<AstObject *>(rawMap1)));
        invert = invert1;
    } else {
        retRawMap = reinterpret_cast<AstMapping *>(astCopy(reinterpret_cast<AstObject *>(rawMap2)));
        invert = invert2;
    }
    astAnnul(reinterpret_cast<AstObject *>(rawMap1));
    astAnnul(reinterpret_cast<AstObject *>(rawMap2));
    assertOK();
 
    // If the mapping's internal invert flag does not match the value used when the CmpMap was made
    // then invert the mapping. Note that it is not possible to create such objects in astshim
    // but it is possible to read in objects created by other software.
    if (invert != astGetI(retRawMap, "Invert")) {
        astInvert(retRawMap);
        assertOK();
    }
 
    return Object::fromAstObject<Class>(reinterpret_cast<AstObject *>(retRawMap), copy);
}

◆ fromAstObject()

template<typename Class >

template std::shared_ptr< Object > ast::Object::fromAstObject< Object >	(	AstObject *	rawObj,
		bool	copy )

staticinherited

Given a bare AST object pointer return a shared pointer to an ast::Object of the correct type.

The returned object takes ownership of the pointer. This is almost always what you want, for instance astDecompose returns shallow copies of the internal pointers.

Template Parameters

Class The class of the returned shared pointer. (The actual class will be the correct class of rawPtr.)

Parameters

[in]	rawObj	A bare AST object pointer
[in]	copy	If True then make a deep copy of the pointer (and free the original)

Definition at line 138 of file Object.cc.

                                                                       {
    AstObject *rawObjCopy = rawObj;
    if (copy) {
        rawObjCopy = reinterpret_cast<AstObject *>(astCopy(rawObj));
        astAnnul(rawObj);
    }
    assertOK(rawObjCopy);
 
    // Make the appropriate ast shim object and dynamically cast to the desired output type
    auto retObjectBeforeCast = Object::_basicFromAstObject(rawObjCopy);
    auto retObject = std::dynamic_pointer_cast<Class>(retObjectBeforeCast);
    if (!retObject) {
        std::ostringstream os;
        os << "The component is of type " << retObject->getClassName()
           << ", which could not be cast to the desired type " << typeid(Class).name();
        throw std::runtime_error(os.str());
    }
    return retObject;
}

◆ fromString()

static std::shared_ptr< Object > ast::Object::fromString ( std::string const & str )

inlinestaticinherited

Construct an Object from a string, using astFromString.

Definition at line 88 of file Object.h.

                                                                  {
        auto *rawPtr = reinterpret_cast<AstObject *>(astFromString(str.c_str()));
        assertOK(rawPtr);
        return Object::_basicFromAstObject(rawPtr);
    }

◆ getB()

bool ast::Object::getB ( std::string const & attrib ) const

inlineprotectedinherited

Get the value of an attribute as a bool.

If possible, the attribute value is converted to the type you request.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 348 of file Object.h.

                                             {
        bool val = astGetI(getRawPtr(), attrib.c_str());
        assertOK();
        return val;
    }

◆ getC()

std::string const ast::Object::getC ( std::string const & attrib ) const

inlineprotectedinherited

Get the value of an attribute as a string.

If possible, the attribute value is converted to the type you request.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 361 of file Object.h.

                                                        {
        char const *rawval = astGetC(getRawPtr(), attrib.c_str());
        assertOK();
        return std::string(rawval);
    }

◆ getClassName()

std::string ast::Object::getClassName ( ) const

inlineinherited

Get Class: the name of the class (e.g.

ZoomMap)

Note: if AST returns "CmpMap" then the name will be changed to "SeriesMap" or "ParallelMap", as appropriate.

Definition at line 139 of file Object.h.

139{ return detail::getClassName(getRawPtr()); }

ast::detail::getClassName

std::string getClassName(AstObject const *rawObj)

Get the AST class name, changing CmpMap to SeriesMap or ParallelMap as appropriate.

Definition utils.cc:37

◆ getD()

double ast::Object::getD ( std::string const & attrib ) const

inlineprotectedinherited

Get the value of an attribute as a double.

If possible, the attribute value is converted to the type you request.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 374 of file Object.h.

                                               {
        double val = astGetD(getRawPtr(), attrib.c_str());
        assertOK();
        return val;
    }

◆ getF()

float ast::Object::getF ( std::string const & attrib ) const

inlineprotectedinherited

Get the value of an attribute as a float.

If possible, the attribute value is converted to the type you request.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 387 of file Object.h.

                                              {
        float val = astGetF(getRawPtr(), attrib.c_str());
        assertOK();
        return val;
    }

◆ getI()

int ast::Object::getI ( std::string const & attrib ) const

protectedinherited

Get the value of an attribute as an int.

If possible, the attribute value is converted to the type you request.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 178 of file Object.cc.

                                              {
    int val = astGetI(getRawPtr(), attrib.c_str());
    assertOK();
    return val;
}

◆ getID()

std::string ast::Object::getID ( ) const

inlineinherited

Get ID: object identification string that is not copied.

Definition at line 142 of file Object.h.

142{ return getC("ID"); }

ast::Object::getC

std::string const getC(std::string const &attrib) const

Get the value of an attribute as a string.

Definition Object.h:361

◆ getIdent()

std::string ast::Object::getIdent ( ) const

inlineinherited

Get Ident: object identification string that is copied.

Definition at line 145 of file Object.h.

145{ return getC("Ident"); }

◆ getIsLinear()

bool ast::Mapping::getIsLinear ( ) const

inlineinherited

Get IsLinear: is the Mapping linear?

Definition at line 100 of file Mapping.h.

100{ return getB("IsLinear"); }

ast::Object::getB

bool getB(std::string const &attrib) const

Get the value of an attribute as a bool.

Definition Object.h:348

◆ getIsSimple()

bool ast::Mapping::getIsSimple ( ) const

inlineinherited

Get IsSimple: has the mapping been simplified?

Definition at line 87 of file Mapping.h.

87{ return getI("IsSimple"); }

ast::Object::getI

int getI(std::string const &attrib) const

Get the value of an attribute as an int.

Definition Object.cc:178

◆ getL()

long int ast::Object::getL ( std::string const & attrib ) const

inlineprotectedinherited

Get the value of an attribute as a long int.

If possible, the attribute value is converted to the type you request.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 409 of file Object.h.

                                                 {
        long int val = astGetL(getRawPtr(), attrib.c_str());
        assertOK();
        return val;
    }

◆ getNatLat()

double ast::WcsMap::getNatLat ( ) const

inline

get NatLat: native latitude of the reference point of a FITS-WCS projection.

Definition at line 227 of file WcsMap.h.

227{ return getD("NatLat"); }

ast::Object::getD

double getD(std::string const &attrib) const

Get the value of an attribute as a double.

Definition Object.h:374

◆ getNatLon()

double ast::WcsMap::getNatLon ( ) const

inline

get NatLon: native longitude of the reference point of a FITS-WCS projection.

Definition at line 230 of file WcsMap.h.

230{ return getD("NatLon"); }

◆ getNIn()

int ast::Mapping::getNIn ( ) const

inlineinherited

Get NIn: the number of input axes.

Definition at line 77 of file Mapping.h.

77{ return getI("NIn"); }

◆ getNObject()

int ast::Object::getNObject ( ) const

inlineinherited

Get NObject: number of AST objects in existence of the same type as the underlying AST class.

Warning: Intended only for debugging astshim.

Definition at line 153 of file Object.h.

153{ return getI("NObject"); }

◆ getNOut()

int ast::Mapping::getNOut ( ) const

inlineinherited

Get NOut: the number of output axes.

Definition at line 82 of file Mapping.h.

82{ return getI("NOut"); }

◆ getObjSize()

int ast::Object::getObjSize ( ) const

inlineinherited

Get ObjSize: the in-memory size of the AST object in bytes.

Definition at line 156 of file Object.h.

156{ return getI("ObjSize"); }

◆ getPVi_m()

double ast::WcsMap::getPVi_m	(	int	i,
		int	m ) const

inline

Get PVi_m for one value of i and m: a FITS-WCS projection parameter.

Parameters

[in]	i	Axis index, starting at 1
[in]	m	Parameter number, in range 1 to PVMax

Definition at line 238 of file WcsMap.h.

                                        {
        std::stringstream os;
        os << "PV" << i << "_" << m;
        return getD(os.str());
    }

◆ getPVMax()

int ast::WcsMap::getPVMax ( int axis ) const

inline

Get PVMax(axis) for one axis: maximum number of FITS-WCS projection parameters.

Definition at line 245 of file WcsMap.h.

245{ return getI(detail::formatAxisAttr("PVMax", axis)); }

ast::detail::formatAxisAttr

std::string formatAxisAttr(std::string const &name, int axis)

Format an axis-specific attribute by appending the axis index.

Definition utils.h:79

◆ getRawPtr() [1/2]

AstObject * ast::Object::getRawPtr ( )

inlineinherited

Get the raw AST pointer.

Intended for internal use only, but cannot be made protected without endless "friend class" declarations.

Definition at line 294 of file Object.h.

294{ return &*_objPtr; };

◆ getRawPtr() [2/2]

AstObject const * ast::Object::getRawPtr ( ) const

inlineinherited

Get the raw AST pointer.

Intended for internal use only, but cannot be made protected without endless "friend class" declarations.

Definition at line 292 of file Object.h.

292{ return &*_objPtr; };

◆ getRefCount()

int ast::Object::getRefCount ( ) const

inlineinherited

Get RefCount: number of active pointers to the underlying AST object.

Warning: Intended only for debugging astshim.

Definition at line 163 of file Object.h.

163{ return getI("RefCount"); }

◆ getReport()

bool ast::Mapping::getReport ( ) const

inlineinherited

Get Report: report transformed coordinates to stdout?

Definition at line 105 of file Mapping.h.

105{ return getB("Report"); }

◆ getUseDefs()

bool ast::Object::getUseDefs ( ) const

inlineinherited

Get UseDefs: allow use of default values for Object attributes?

Definition at line 166 of file Object.h.

166{ return getB("UseDefs"); }

◆ getWcsAxis()

std::pair< int, int > ast::WcsMap::getWcsAxis ( ) const

inline

Get WcsAxis(lonlat) FITS-WCS projection axis for longitude, latitude.

Definition at line 250 of file WcsMap.h.

                                         {
        return std::make_pair(getI(detail::formatAxisAttr("WcsAxis", 1)),
                              getI(detail::formatAxisAttr("WcsAxis", 2)));
    }

◆ getWcsType()

WcsType ast::WcsMap::getWcsType ( ) const

inline

Get WcsType: FITS-WCS projection type.

Definition at line 256 of file WcsMap.h.

256{ return static_cast<WcsType>(getI("WcsType")); }

ast::WcsType

WcsType

WCS types that give the projection type code (in upper case) as used in the FITS-WCS "CTYPEi" keyword...

Definition WcsMap.h:48

◆ hasAttribute()

bool ast::Object::hasAttribute ( std::string const & attrib ) const

inlineinherited

Does this object have an attribute with the specified name?

Definition at line 127 of file Object.h.

                                                     {
        bool ret = astHasAttribute(getRawPtr(), attrib.c_str());
        assertOK();
        return ret;
    }

◆ hasForward()

bool ast::Mapping::hasForward ( ) const

inlineinherited

Is the forward transform available?

Note: This gets the TranForward attribute, but is named hasForward instead of getTranForward for clarity, since it does not return a transform.

Definition at line 114 of file Mapping.h.

114{ return getB("TranForward"); }

◆ hasInverse()

bool ast::Mapping::hasInverse ( ) const

inlineinherited

Is the inverse transform available?

Note: This gets the TranInverse attribute, but is named hasInverse instead of getTranInverse for clarity, since it does not return a transform.

Definition at line 123 of file Mapping.h.

123{ return getB("TranInverse"); }

◆ inverted()

std::shared_ptr< Mapping > ast::Mapping::inverted ( ) const

inherited

Get an inverse mapping.

An inverse mapping is a deep copy of a mapping whose Invert attribute has been toggled, as indicated by isInverted. This swaps the meaning of "input" and "output", and of "forward" and "inverse". Thus it swaps the behavior of applyForward and applyInverse, getNIn and getNOut, hasForward and hasInverse and so on.

Note that the inverse mapping contains exactly the same model coefficients as the original, but they are used by applyInverse instead of applyForward. Thus for example if a ZoomMap has a zoom factor of 4.0 then its inverse also reports a zoom factor of 4.0 (despite behaving like an uninverted ZoomMap with zoom factor of 0.25).

Definition at line 41 of file Mapping.cc.

                                               {
    auto rawCopy = reinterpret_cast<AstMapping *>(astCopy(getRawPtr()));
    astInvert(rawCopy);
    assertOK(reinterpret_cast<AstObject *>(rawCopy));
    // use false because the pointer has already been copied
    return Object::fromAstObject<Mapping>(reinterpret_cast<AstObject *>(rawCopy), false);
}

◆ isInverted()

bool ast::Mapping::isInverted ( ) const

inlineinherited

Is this an inverted mapping?

Note: this gets the Invert attribute. This method is not called getInvert because that sounds like it might return the inverse.

Definition at line 95 of file Mapping.h.

95{ return getB("Invert"); }

◆ linearApprox()

Array2D ast::Mapping::linearApprox	(	PointD const &	lbnd,
		PointD const &	ubnd,
		double	tol ) const

inherited

Compute a linear approximation to the forward transformation.

Parameters

[in]	lbnd	Input point defining the lower bounds of the box over which the linear approximation is computed.
[in]	ubnd	Input point defining the upper bounds of the box over which the linear approximation is computed.
[in]	tol	The maximum permitted deviation from linearity, expressed as apositive Cartesian displacement in the output coordinate space. If a linear fit to the forward transformation of the Mapping deviates from the true transformation by more than this amount at any point which is tested, then raise an exception.

Returns

The co-efficients of the linear approximation to the specified transformation, as an 1 + nIn x nOut array. The first index is [constant, gradiant for input 1, gradiant for input 2...] and the second index is [output 1, output 2, ...]. For example, if the Mapping has 2 inputs and 3 outputs then the coefficients are:

X_out = fit[0, 0] + fit[1, 0] X_in + fit[2, 0] Y_in
Y_out = fit[0, 1] + fit[1, 1] X_in + fit[2, 1] Y_in
Z_out = fit[0, 2] + fit[1, 2] X_in + fit[2, 2] Y_in

Exceptions

std::runtime_error if the forward transformation cannot be modeled to within the specified tol.

Definition at line 49 of file Mapping.cc.

                                                                                      {
    int const nIn = getNIn();
    int const nOut = getNOut();
    detail::assertEqual(lbnd.size(), "lbnd.size", static_cast<std::size_t>(nIn), "nIn");
    detail::assertEqual(ubnd.size(), "ubnd.size", static_cast<std::size_t>(nIn), "nIn");
    Array2D fit = ndarray::allocate(ndarray::makeVector(1 + nIn, nOut));
    int isOK = astLinearApprox(getRawPtr(), lbnd.data(), ubnd.data(), tol, fit.getData());
    assertOK();
    if (!isOK) {
        throw std::runtime_error("Mapping not sufficiently linear");
    }
    return fit;
}

◆ lock()

void ast::Object::lock ( bool wait )

inlineinherited

Lock this object for exclusive use by the calling thread.

The thread-safe public interface to AST is designed so that an error is reported if any thread attempts to use an Object that it has not previously locked for its own exclusive use using this function. When an Object is created, it is initially locked by the thread that creates it, so newly created objects do not need to be explicitly locked. However, if an Object pointer is passed to another thread, the original thread must first unlock it (using astUnlock) and the new thread must then lock it (using astLock) before the new thread can use the Object.

Parameters

[in] wait If the Object is curently locked by another thread then this function will either report an error or block. If a non-zero value is supplied for "wait", the calling thread waits until the object is available for it to use. Otherwise, an error is reported and the function returns immediately without locking the Object.

Notes

The Locked object will belong to the current AST context.
This function returns without action if the Object is already locked by the calling thread.
If simultaneous use of the same object is required by two or more threads, Object::copy should be used to to produce a deep copy of the Object for each thread. Each copy should then be unlocked by the parent thread (i.e. the thread that created the copy), and then locked by the child thread (i.e. the thread that wants to use the copy).
This function returns without action if the AST library has been built without POSIX thread support (i.e. the "-with-pthreads" option was not specified when running the "configure" script).

Definition at line 202 of file Object.h.

                         {
        astLock(getRawPtr(), static_cast<int>(wait));
        assertOK();
    }

◆ makeShim()

template<typename ShimT , typename AstT >

static std::shared_ptr< ShimT > ast::Object::makeShim ( AstObject * p )

inlinestaticprotectedinherited

Functor to make an astshim instance from a raw AST pointer of the corresponding type.

Template Parameters

ShimT	Output astshim class
AstT	Output AST class

Definition at line 310 of file Object.h.

                                                       {
        return std::shared_ptr<ShimT>(new ShimT(reinterpret_cast<AstT *>(p)));
    }

◆ operator!=()

bool ast::Object::operator!= ( Object const & rhs ) const

inlineinherited

Return True if this and rhs are not equal.

See operator== for details

Definition at line 82 of file Object.h.

82 {

83 return !(*this == rhs); };

◆ operator=() [1/2]

WcsMap & ast::WcsMap::operator= ( WcsMap && )

default

◆ operator=() [2/2]

WcsMap & ast::WcsMap::operator= ( WcsMap const & )

delete

◆ operator==()

bool ast::Object::operator== ( Object const & rhs ) const

inherited

Return True if this and rhs are the equal.

For two objects be equal, they both must have the same attributes and all contained objects must be equal.

Definition at line 85 of file Object.cc.

                                               {
    auto thisStr = this->show(false);
    auto rhsStr = rhs.show(false);
    return rhsStr == thisStr;
}

◆ rate()

double ast::Mapping::rate	(	PointD const &	at,
		int	ax1,
		int	ax2 ) const

inlineinherited

Evaluate the rate of change of the Mapping with respect to a specified input, at a specified position.

The result is estimated by interpolating the function using a fourth order polynomial in the neighbourhood of the specified position. The size of the neighbourhood used is chosen to minimise the RMS residual per unit length between the interpolating polynomial and the supplied Mapping function. This method produces good accuracy but can involve evaluating the Mapping 100 or more times.

Parameters

[in]	at	The input position at which the rate of change is to be evaluated.
[in]	ax1	The index of the output for which the rate of change is to be found (1 for first output).
[in]	ax2	The index of the input which is to be varied in order to find the rate of change (1 for the first input).

Returns: The rate of change of Mapping output ax1 with respect to input ax2, evaluated at at, or nan if the value cannot be calculated.

Definition at line 215 of file Mapping.h.

                                                          {
        detail::assertEqual(at.size(), "at.size", static_cast<std::size_t>(getNIn()), "nIn");
        double result = astRate(getRawPtr(), const_cast<double *>(at.data()), ax1, ax2);
        assertOK();
        return result;
    }

◆ same()

bool ast::Object::same ( Object const & other ) const

inlineinherited

Does this contain the same AST object as another?

This is a test of identity, not of equality.

Definition at line 212 of file Object.h.

212{ return astSame(getRawPtr(), other.getRawPtr()); }

◆ set()

void ast::Object::set ( std::string const & setting )

inlineprotectedinherited

Assign a set of attribute values, over-riding any previous values.

The attributes and their new values are specified via a character string, which should contain a comma-separated list of the form: "attribute_1 = value_1, attribute_2 = value_2, ... " where "attribute_n" specifies an attribute name, and the value to the right of each " =" sign should be a suitable textual representation of the value to be assigned. This value will be interpreted according to the attribute's data type.

Notes

Attribute names are not case sensitive and may be surrounded by white space
Attribute names are not case sensitive and may be surrounded by white space.
White space may also surround attribute values, where it will generally be ignored (except for string-valued attributes where it is significant and forms part of the value to be assigned).
To include a literal comma or percent sign in the value assigned to an attribute, the whole attribute value should be enclosed in quotation markes.

Exceptions

std::runtime_error if the attribute is read-only

Definition at line 436 of file Object.h.

                                       {
        astSet(getRawPtr(), "%s", setting.c_str());
        assertOK();
    }

◆ setB()

void ast::Object::setB	(	std::string const &	attrib,
		bool	value )

inlineprotectedinherited

Set the value of an attribute as a bool.

If possible, the type you provide is converted to the actual type of the attribute.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 448 of file Object.h.

                                                   {
        astSetI(getRawPtr(), attrib.c_str(), value);
        assertOK();
    }

◆ setC()

void ast::Object::setC	(	std::string const &	attrib,
		std::string const &	value )

inlineprotectedinherited

Set the value of an attribute as a string.

If possible, the type you provide is converted to the actual type of the attribute.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 460 of file Object.h.

                                                               {
        astSetC(getRawPtr(), attrib.c_str(), value.c_str());
        assertOK();
    }

◆ setD()

void ast::Object::setD	(	std::string const &	attrib,
		double	value )

inlineprotectedinherited

Set the value of an attribute as a double.

If possible, the type you provide is converted to the actual type of the attribute.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 472 of file Object.h.

                                                     {
        astSetD(getRawPtr(), attrib.c_str(), value);
        assertOK();
    }

◆ setF()

void ast::Object::setF	(	std::string const &	attrib,
		float	value )

inlineprotectedinherited

Set the value of an attribute as a float.

If possible, the type you provide is converted to the actual type of the attribute.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 484 of file Object.h.

                                                    {
        astSetF(getRawPtr(), attrib.c_str(), value);
        assertOK();
    }

◆ setI()

void ast::Object::setI	(	std::string const &	attrib,
		int	value )

inlineprotectedinherited

Set the value of an attribute as an int.

If possible, the type you provide is converted to the actual type of the attribute.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 496 of file Object.h.

                                                  {
        astSetI(getRawPtr(), attrib.c_str(), value);
        assertOK();
    }

◆ setID()

void ast::Object::setID ( std::string const & id )

inlineinherited

Set ID: object identification string that is not copied.

Definition at line 215 of file Object.h.

215{ setC("ID", id); }

ast::Object::setC

void setC(std::string const &attrib, std::string const &value)

Set the value of an attribute as a string.

Definition Object.h:460

◆ setIdent()

void ast::Object::setIdent ( std::string const & ident )

inlineinherited

Set Ident: object identification string that is copied.

Definition at line 218 of file Object.h.

218{ setC("Ident", ident); }

◆ setL()

void ast::Object::setL	(	std::string const &	attrib,
		long int	value )

inlineprotectedinherited

Set the value of an attribute as a long int.

If possible, the type you provide is converted to the actual type of the attribute.

Exceptions

std::runtime_error if the attribute does not exist or the value cannot be converted

Definition at line 508 of file Object.h.

                                                       {
        astSetL(getRawPtr(), attrib.c_str(), value);
        assertOK();
    }

◆ setReport()

void ast::Mapping::setReport ( bool report )

inlineinherited

Set Report: report transformed coordinates to stdout?

Definition at line 225 of file Mapping.h.

225{ setB("Report", report); }

ast::Object::setB

void setB(std::string const &attrib, bool value)

Set the value of an attribute as a bool.

Definition Object.h:448

◆ setUseDefs()

void ast::Object::setUseDefs ( bool usedefs )

inlineinherited

Set UseDefs: allow use of default values for Object attributes?

Definition at line 221 of file Object.h.

221{ setB("UseDefs", usedefs); }

◆ show() [1/2]

std::string ast::Object::show ( bool showComments = true ) const

inherited

Return a textual description the object as a string.

Parameters

[in] showComments Show comments?

Definition at line 165 of file Object.cc.

                                              {
    std::ostringstream os;
    show(os, showComments);
    return os.str();
}

◆ show() [2/2]

void ast::Object::show	(	std::ostream &	os,
		bool	showComments = true ) const

inherited

Print a textual description the object to an ostream.

Parameters

[in,out]	os	The stream to which to write the string representation.
[in]	showComments	Show comments?

Definition at line 158 of file Object.cc.

                                                         {
    Stream stream(nullptr, &os);
    Channel ch(stream, showComments ? "" : "Comment=0");
    ch.write(*this);
    assertOK();
}

◆ simplified()

std::shared_ptr< Mapping > ast::Mapping::simplified ( ) const

inlineinherited

Return a simplied version of the mapping (which may be a compound Mapping such as a CmpMap).

Simplification eliminates redundant computational steps and merges separate steps which can be performed more efficiently in a single operation. As a simple example, a Mapping which multiplied coordinates by 5, and then multiplied the result by 10, could be simplified to a single step which multiplied by 50. Similarly, a Mapping which multiplied by 5, and then divided by 5, could be reduced to a simple copying operation.

This function should typically be applied to Mappings which have undergone substantial processing or have been formed by merging other Mappings. It is of potential benefit, for example, in reducing execution time if applied before using a Mapping to transform a large number of coordinates.

Note: If the supplied Mapping is a FrameSet, the returned Mapping will be a deep copy of the supplied FrameSet in which all the inter-Frame Mappings have been simplified. Mappings that have a set value for their ref Object_Ident "Ident" attribute are unchanged by simplification. This is so that their individual identity is preserved. This restriction does not apply to the simplification of Frames. The returned mapping is always independent of the original (a deep copy), unlike astSimplify.

Definition at line 248 of file Mapping.h.

                                              {
        AstObject *rawSimpMap = reinterpret_cast<AstObject *>(astSimplify(getRawPtr()));
        assertOK(rawSimpMap);
        return Object::fromAstObject<Mapping>(rawSimpMap, true);
    }

◆ test()

bool ast::Object::test ( std::string const & attrib ) const

inlineinherited

Has this attribute been explicitly set (and not subsequently cleared)?

Warning: Unlike the underlying astTest function, throws an exception if an error results

Notes

Attribute names are not case sensitive and may be surrounded by white space.
As you might expect, the returned value for a read-only attribute is always false.

Exceptions

std::runtime_error if an error results.

Definition at line 250 of file Object.h.

                                             {
        bool res = astTest(getRawPtr(), attrib.c_str());
        assertOK();
        return res;
    }

◆ then()

SeriesMap ast::Mapping::then ( Mapping const & next ) const

inherited

Return a series compound mapping this(first(input)) containing shallow copies of the original.

Parameters

[in] next the mapping whose input is the output of this mapping

Exceptions

std::invalid_argument if the number of input axes of next does not match the number of output axes of this mapping.

Warning: The contained mappings are shallow copies (just like AST); if you want deep copies then make them manually.

Definition at line 37 of file Mapping.cc.

37{ return SeriesMap(*this, next); }

◆ tranGridForward() [1/2]

void ast::Mapping::tranGridForward	(	PointI const &	lbnd,
		PointI const &	ubnd,
		double	tol,
		int	maxpix,
		Array2D const &	to ) const

inlineinherited

Transform a grid of points in the forward direction.

Parameters

[in]	lbnd	The coordinates of the centre of the first pixel in the input grid along each dimension, size = nIn
[in]	ubnd	The coordinates of the centre of the last pixel in the input grid along each dimension, size = nIn
[in]	tol	The maximum tolerable geometrical distortion which may be introduced as a result of approximating non-linear Mappings by a set of piece-wise linear transformations. This should be expressed as a displacement within the output coordinate system of the Mapping.

If piece-wise linear approximation is not required, a value of zero may be given. This will ensure that the Mapping is used without any approximation, but may increase execution time.

If the value is too high, discontinuities between the linear approximations used in adjacent panel will be higher. If this is a problem, reduce the tolerance value used.

Parameters

[in]	maxpix	A value which specifies an initial scale size (in input grid points) for the adaptive algorithm which approximates non-linear Mappings with piece-wise linear transformations. Normally, this should be a large value (larger than any dimension of the region of the input grid being used). In this case, a first attempt to approximate the Mapping by a linear transformation will be made over the entire input region. If a smaller value is used, the input region will first be divided into sub-regions whose size does not exceed " maxpix" grid points in any dimension. Only at this point will attempts at approximation commence. This value may occasionally be useful in preventing false convergence of the adaptive algorithm in cases where the Mapping appears approximately linear on large scales, but has irregularities (e.g. holes) on smaller scales. A value of, say, 50 to 100 grid points can also be employed as a safeguard in general-purpose software, since the effect on performance is minimal. If too small a value is given, it will have the effect of inhibiting linear approximation altogether (equivalent to setting " tol" to zero). Although this may degrade performance, accurate results will still be obtained.
[in]	to	Computed points, with dimensions (nPts, nOut), where nPts the desired number of points

Definition at line 358 of file Mapping.h.

                                                  {
        _tranGrid(lbnd, ubnd, tol, maxpix, true, to);
    }

◆ tranGridForward() [2/2]

Array2D ast::Mapping::tranGridForward	(	PointI const &	lbnd,
		PointI const &	ubnd,
		double	tol,
		int	maxpix,
		int	nPts ) const

inlineinherited

Transform a grid of points in the inverse direction, returning the results as a new Array2D.

See the overload of tranGridForward that outputs the data as the last argument for more information

Definition at line 369 of file Mapping.h.

                                                                                                            {
        Array2D to = ndarray::allocate(nPts, getNOut());
        _tranGrid(lbnd, ubnd, tol, maxpix, true, to);
        return to;
    }

◆ tranGridInverse() [1/2]

void ast::Mapping::tranGridInverse	(	PointI const &	lbnd,
		PointI const &	ubnd,
		double	tol,
		int	maxpix,
		Array2D const &	to ) const

inlineinherited

Transform a grid of points in the inverse direction.

See tranGridForward for the arguments, swapping nIn and nOut

Definition at line 380 of file Mapping.h.

                                                  {
        _tranGrid(lbnd, ubnd, tol, maxpix, false, to);
    }

◆ tranGridInverse() [2/2]

Array2D ast::Mapping::tranGridInverse	(	PointI const &	lbnd,
		PointI const &	ubnd,
		double	tol,
		int	maxpix,
		int	nPts ) const

inlineinherited

Transform a grid of points in the inverse direction.

See tranGridForward for the arguments, swapping nIn and nOut

Definition at line 390 of file Mapping.h.

                                                                                                            {
        Array2D to = ndarray::allocate(nPts, getNIn());
        _tranGrid(lbnd, ubnd, tol, maxpix, false, to);
        return to;
    }

◆ under()

ParallelMap ast::Mapping::under ( Mapping const & next ) const

inherited

Return a parallel compound mapping containing shallow copies of the original.

The resulting mapping has getNIn() + next.getNIn() inputs and getNOut() + next.getNOut() outputs. The first getNIn() axes of input are transformed by this mapping, producing the first getNOut() axes of output. The remaining axes of input are processed by next, resulting in the remaining axes of output.

The name comes the way vectors are sometimes shown for matrix multiplication: vertically, with the first axis at the bottom and the last axis at the top.

Parameters

[in] next the mapping that processes the final next.getNin() axes of input to produce the final next.getNout() axes of output.

Warning: The contained mappings are shallow copies (just like AST); if you want deep copies then make them manually.

Definition at line 39 of file Mapping.cc.

39{ return ParallelMap(*this, next); }

◆ unlock()

void ast::Object::unlock ( bool report = false )

inlineinherited

Unlock this object previously locked using lock, so that other threads can use this object.

See lock for further details.

Parameters

[in] report If true, an error will be reported if the supplied Object, or any Object contained within the supplied Object, is not currently locked by the running thread. If false, such Objects will be left unchanged, and no error will be reported.

Notes

This function attempts to execute even if AST's global error status is set, but no further error report will be made if it subsequently fails under these circumstances.
All unlocked Objects are excluded from AST context handling until they are re-locked using astLock.
This function returns without action if the Object is not currently locked by any thread. If it is locked by the running thread, it is unlocked. If it is locked by another thread, an error will be reported if "error" is non-zero.
This function returns without action if the AST library has been built without POSIX thread support (i.e. the "-with-pthreads" option was not specified when running the "configure" script).

Definition at line 280 of file Object.h.

                                     {
        astUnlock(getRawPtr(), static_cast<int>(report));
        assertOK();
    }

Friends And Related Symbol Documentation

◆ Object

friend class Object

friend

Definition at line 147 of file WcsMap.h.

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

/j/snowflake/release/lsstsw/stack/lsst-scipipe-9.0.0/Linux64/astshim/g3156d2b45e+41e33cbcdc/include/astshim/WcsMap.h

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Member Functions

Friends

Detailed Description

Attributes

Notes

Member Typedef Documentation

◆ ObjectPtr

Constructor & Destructor Documentation

◆ WcsMap() [1/4]

Examples

◆ ~WcsMap()

◆ WcsMap() [2/4]

◆ WcsMap() [3/4]

◆ WcsMap() [4/4]

Member Function Documentation

◆ applyForward() [1/3]

◆ applyForward() [2/3]

◆ applyForward() [3/3]

◆ applyInverse() [1/3]

◆ applyInverse() [2/3]

◆ applyInverse() [3/3]

◆ clear()

◆ copy()

◆ copyImpl()

◆ copyPolymorphic()

◆ decompose()

◆ fromAstObject()

◆ fromString()

◆ getB()

◆ getC()

◆ getClassName()

◆ getD()

◆ getF()

◆ getI()

◆ getID()

◆ getIdent()

◆ getIsLinear()

◆ getIsSimple()

◆ getL()

◆ getNatLat()

◆ getNatLon()

◆ getNIn()

◆ getNObject()

◆ getNOut()

◆ getObjSize()

◆ getPVi_m()

◆ getPVMax()

◆ getRawPtr() [1/2]

◆ getRawPtr() [2/2]

◆ getRefCount()

◆ getReport()

◆ getUseDefs()

◆ getWcsAxis()

◆ getWcsType()

◆ hasAttribute()

◆ hasForward()

◆ hasInverse()

◆ inverted()

◆ isInverted()

◆ linearApprox()

◆ lock()

Notes

◆ makeShim()

◆ operator!=()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ operator==()

◆ rate()

◆ same()

◆ set()

Notes

◆ setB()

◆ setC()

◆ setD()

◆ setF()

◆ setI()