DGtal::Filtered2x2DetComputer< TDetComputer > Class Template Reference

Aim: Class that provides a way of computing the sign of the determinant of a 2x2 matrix from its four coefficients, ie. More...

#include <DGtal/geometry/tools/determinant/Filtered2x2DetComputer.h>

Public Types
typedef TDetComputer::ArgumentInteger	ArgumentInteger
typedef ArgumentInteger	Integer
typedef ArgumentInteger	argument_type
typedef TDetComputer::ResultInteger	ResultInteger
typedef ResultInteger	Value
typedef ResultInteger	result_type

Public Member Functions
	BOOST_CONCEPT_ASSERT ((C2x2DetComputer< TDetComputer >))
	BOOST_STATIC_ASSERT ((std::numeric_limits< ArgumentInteger >::is_iec559))
void	init (const ArgumentInteger &aA, const ArgumentInteger &aB)
ResultInteger	operator() (const ArgumentInteger &aX, const ArgumentInteger &aY) const
ResultInteger	operator() (const ArgumentInteger &aA, const ArgumentInteger &aB, const ArgumentInteger &aX, const ArgumentInteger &aY)
void	selfDisplay (std::ostream &out) const
bool	isValid () const

Private Attributes
ArgumentInteger	myA
ArgumentInteger	myB
TDetComputer	myDetComputer

Detailed Description

template<typename TDetComputer>
class DGtal::Filtered2x2DetComputer< TDetComputer >

Aim: Class that provides a way of computing the sign of the determinant of a 2x2 matrix from its four coefficients, ie.

\( \begin{vmatrix} a & x \\ b & y \end{vmatrix} \)

The coefficients must be integers, with an absolute value less than 2^53, of type 'double'.

It returns:

• a strictly positive value if \( ay - bx > 0\),
• a strictly negative value if \( ay - bx < 0 \),
• 0 if \( ay - bx = 0 \).

If the result of \( ay - bx \) is not null, the IEC-559 / IEEE-754 standard guarantees that the result is not zero (filtering step). Otherwise, we use another method to conclude.

This class is a model of C2x2DetComputer.

Template Parameters

TDetComputer

any model of C2x2DetComputer

Examples

geometry/tools/determinant/exampleInHalfPlane.cpp.

Definition at line 83 of file Filtered2x2DetComputer.h.

Member Typedef Documentation

argument_type

template<typename TDetComputer >

typedef ArgumentInteger DGtal::Filtered2x2DetComputer< TDetComputer >::argument_type

STL alias of type ArgumentInteger

Definition at line 104 of file Filtered2x2DetComputer.h.

ArgumentInteger

template<typename TDetComputer >

typedef TDetComputer::ArgumentInteger DGtal::Filtered2x2DetComputer< TDetComputer >::ArgumentInteger

Type of integer for the input coefficients of the 2x2 matrix

Definition at line 92 of file Filtered2x2DetComputer.h.

Integer

template<typename TDetComputer >

typedef ArgumentInteger DGtal::Filtered2x2DetComputer< TDetComputer >::Integer

DGtal alias of type ArgumentInteger

Definition at line 100 of file Filtered2x2DetComputer.h.

result_type

template<typename TDetComputer >

typedef ResultInteger DGtal::Filtered2x2DetComputer< TDetComputer >::result_type

STL alias of type ResultInteger

Definition at line 117 of file Filtered2x2DetComputer.h.

ResultInteger

template<typename TDetComputer >

typedef TDetComputer::ResultInteger DGtal::Filtered2x2DetComputer< TDetComputer >::ResultInteger

Type of integer for the returned determinant

Definition at line 109 of file Filtered2x2DetComputer.h.

Value

template<typename TDetComputer >

typedef ResultInteger DGtal::Filtered2x2DetComputer< TDetComputer >::Value

DGtal alias type of ResultInteger

Definition at line 113 of file Filtered2x2DetComputer.h.

Member Function Documentation

BOOST_CONCEPT_ASSERT()

template<typename TDetComputer >

DGtal::Filtered2x2DetComputer< TDetComputer >::BOOST_CONCEPT_ASSERT

(

(C2x2DetComputer< TDetComputer >)

)

BOOST_STATIC_ASSERT()

template<typename TDetComputer >

DGtal::Filtered2x2DetComputer< TDetComputer >::BOOST_STATIC_ASSERT

(

(std::numeric_limits< ArgumentInteger >::is_iec559)

)

init()

template<typename TDetComputer >

void DGtal::Filtered2x2DetComputer< TDetComputer >::init	(	const ArgumentInteger &	aA,
		const ArgumentInteger &	aB
	)

Initialisation.

Parameters

aA	0-component of the first column vector
aB	1-component of the first column vector

See also

operator()

isValid()

template<typename TDetComputer >

bool DGtal::Filtered2x2DetComputer< TDetComputer >::isValid

(

)

const

Checks the validity/consistency of the object.

Returns

'true' if the object is valid, 'false' otherwise.

operator()() [1/2]

template<typename TDetComputer >

ResultInteger DGtal::Filtered2x2DetComputer< TDetComputer >::operator()	(	const ArgumentInteger &	aA,
		const ArgumentInteger &	aB,
		const ArgumentInteger &	aX,
		const ArgumentInteger &	aY
	)

Operator.

Parameters

aA	0-component of the first column vector
aB	1-component of the first column vector
aX	0-component of the second column vector
aY	1-component of the second column vector

Returns

determinant of the 2x2 matrix that consists of the two above column vectors, ie. aA . aY - aB . aX

operator()() [2/2]

template<typename TDetComputer >

ResultInteger DGtal::Filtered2x2DetComputer< TDetComputer >::operator()	(	const ArgumentInteger &	aX,
		const ArgumentInteger &	aY
	)		const

Incremental operator.

Precondition

init must be called before

Parameters

aX	0-component of the second column vector
aY	1-component of the second column vector

Returns

the 2x2 matrix determinant, ie. myAX . aY - myBY . aX

selfDisplay()

template<typename TDetComputer >

void DGtal::Filtered2x2DetComputer< TDetComputer >::selfDisplay

(

std::ostream &

out

)

const

Writes/Displays the object on an output stream.

Parameters

out	the output stream where the object is written.

Field Documentation

myA

template<typename TDetComputer >

ArgumentInteger DGtal::Filtered2x2DetComputer< TDetComputer >::myA

private

Data member used to store the 0-component of the first column vector, ie. a.

Definition at line 176 of file Filtered2x2DetComputer.h.

myB

template<typename TDetComputer >

ArgumentInteger DGtal::Filtered2x2DetComputer< TDetComputer >::myB

private

Data member used to store the 1-component of the first column vector, ie. b.

Definition at line 181 of file Filtered2x2DetComputer.h.

myDetComputer

template<typename TDetComputer >

TDetComputer DGtal::Filtered2x2DetComputer< TDetComputer >::myDetComputer

mutableprivate

Object that can return (the sign of) the determinant, after the filtering.

Definition at line 186 of file Filtered2x2DetComputer.h.

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

• Filtered2x2DetComputer.h