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lsst::sphgeom::Interval< Derived, Scalar > Class Template Reference

Interval represents a closed interval of the real numbers by its upper and lower bounds. More...

#include <Interval.h>

Public Member Functions

 Interval ()
 This constructor creates an empty interval. More...
 
 Interval (Scalar x)
 This constructor creates a closed interval containing only x. More...
 
 Interval (Scalar x, Scalar y)
 This constructor creates an interval from the given endpoints. More...
 
bool operator== (Interval const &i) const
 Two closed intervals are equal if their endpoints are the same, or both are empty. More...
 
bool operator!= (Interval const &i) const
 
bool operator== (Scalar x) const
 A closed interval is equal to a point x if both endpoints equal x. More...
 
bool operator!= (Scalar x) const
 
Scalar getA () const
 getA returns the lower endpoint of this interval. More...
 
Scalar getB () const
 getB returns the upper endpoint of this interval. More...
 
bool isEmpty () const
 isEmpty returns true if this interval does not contain any points. More...
 
Scalar getCenter () const
 getCenter returns the center of this interval. More...
 
Scalar getSize () const
 getSize returns the size (length, width) of this interval. More...
 
IntervaldilateBy (Scalar x)
 For positive x, dilateBy morphologically dilates this interval by [-x,x], which is equivalent to the taking the Minkowski sum with [-x,x]. More...
 
IntervalerodeBy (Scalar x)
 
Derived dilatedBy (Scalar x) const
 
Derived erodedBy (Scalar x) const
 
bool contains (Scalar x) const
 
bool contains (Interval const &x) const
 
bool isDisjointFrom (Scalar x) const
 
bool isDisjointFrom (Interval const &x) const
 
bool intersects (Scalar x) const
 
bool intersects (Interval const &x) const
 
bool isWithin (Scalar x) const
 
bool isWithin (Interval const &x) const
 
Relationship relate (Scalar x) const
 
Relationship relate (Interval const &x) const
 
IntervalclipTo (Scalar x)
 
IntervalclipTo (Interval const &x)
 
Derived clippedTo (Scalar x) const
 
Derived clippedTo (Interval const &x) const
 
IntervalexpandTo (Scalar x)
 
IntervalexpandTo (Interval const &x)
 
Derived expandedTo (Scalar x) const
 
Derived expandedTo (Interval const &x) const
 

Detailed Description

template<typename Derived, typename Scalar>
class lsst::sphgeom::Interval< Derived, Scalar >

Interval represents a closed interval of the real numbers by its upper and lower bounds.

It is parameterized by the Scalar type, which must be constructible from a double.

An interval with identical upper and lower bounds contains a single point, and is equal to that scalar bound.

An interval with an upper bound less than its lower bound is empty (contains no points), as are intervals with NaN as either bound.

Definition at line 48 of file Interval.h.

Constructor & Destructor Documentation

◆ Interval() [1/3]

template<typename Derived , typename Scalar >
lsst::sphgeom::Interval< Derived, Scalar >::Interval ( )
inline

This constructor creates an empty interval.

Definition at line 51 of file Interval.h.

51 : _a(1.0), _b(0.0) {}

◆ Interval() [2/3]

template<typename Derived , typename Scalar >
lsst::sphgeom::Interval< Derived, Scalar >::Interval ( Scalar  x)
inlineexplicit

This constructor creates a closed interval containing only x.

Definition at line 54 of file Interval.h.

54 : _a(x), _b(x) {}

◆ Interval() [3/3]

template<typename Derived , typename Scalar >
lsst::sphgeom::Interval< Derived, Scalar >::Interval ( Scalar  x,
Scalar  y 
)
inline

This constructor creates an interval from the given endpoints.

Definition at line 57 of file Interval.h.

57 : _a(x), _b(y) {}

Member Function Documentation

◆ clippedTo() [1/2]

template<typename Derived , typename Scalar >
Derived lsst::sphgeom::Interval< Derived, Scalar >::clippedTo ( Interval< Derived, Scalar > const &  x) const
inline

clippedTo returns the intersection of this interval and x.

Definition at line 185 of file Interval.h.

185  {
186  return Interval(*this).clipTo(x);
187  }

◆ clippedTo() [2/2]

template<typename Derived , typename Scalar >
Derived lsst::sphgeom::Interval< Derived, Scalar >::clippedTo ( Scalar  x) const
inline

clippedTo returns the intersection of this interval and x.

Definition at line 183 of file Interval.h.

183 { return Interval(*this).clipTo(x); }

◆ clipTo() [1/2]

template<typename Derived , typename Scalar >
Interval& lsst::sphgeom::Interval< Derived, Scalar >::clipTo ( Interval< Derived, Scalar > const &  x)
inline

clipTo shrinks this interval until all its points are in x.

Definition at line 170 of file Interval.h.

170  {
171  if (x.isEmpty()) {
172  *this = x;
173  } else if (!isEmpty()) {
174  _a = std::max(_a, x._a);
175  _b = std::min(_b, x._b);
176  }
177  return *this;
178  }

◆ clipTo() [2/2]

template<typename Derived , typename Scalar >
Interval& lsst::sphgeom::Interval< Derived, Scalar >::clipTo ( Scalar  x)
inline

clipTo shrinks this interval until all its points are in x.

Definition at line 159 of file Interval.h.

159  {
160  if (x != x) {
161  _a = x;
162  _b = x;
163  } else {
164  _a = std::max(_a, x);
165  _b = std::min(_b, x);
166  }
167  return *this;
168  }

◆ contains() [1/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::contains ( Interval< Derived, Scalar > const &  x) const
inline

contains returns true if the intersection of this interval and x is equal to x.

Definition at line 102 of file Interval.h.

102  {
103  if (x.isEmpty()) {
104  return true;
105  } else if (isEmpty()) {
106  return false;
107  }
108  return _a <= x._a && _b >= x._b;
109  }

◆ contains() [2/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::contains ( Scalar  x) const
inline

contains returns true if the intersection of this interval and x is equal to x.

Definition at line 98 of file Interval.h.

98  {
99  return (_a <= x && x <= _b) || x != x;
100  }

◆ dilateBy()

template<typename Derived , typename Scalar >
Interval& lsst::sphgeom::Interval< Derived, Scalar >::dilateBy ( Scalar  x)
inline

For positive x, dilateBy morphologically dilates this interval by [-x,x], which is equivalent to the taking the Minkowski sum with [-x,x].

For negative x, it morphologically erodes this interval by [x,-x]. If x is zero or NaN, or this interval is empty, there is no effect.

Definition at line 230 of file Interval.h.

230  {
231  if (x == x && !isEmpty()) {
232  _a = _a - x;
233  _b = _b + x;
234  }
235  return *this;
236  }

◆ dilatedBy()

template<typename Derived , typename Scalar >
Derived lsst::sphgeom::Interval< Derived, Scalar >::dilatedBy ( Scalar  x) const
inline

Definition at line 239 of file Interval.h.

239 { return Interval(*this).dilateBy(x); }

◆ erodeBy()

template<typename Derived , typename Scalar >
Interval& lsst::sphgeom::Interval< Derived, Scalar >::erodeBy ( Scalar  x)
inline

Definition at line 238 of file Interval.h.

238 { return dilateBy(-x); }

◆ erodedBy()

template<typename Derived , typename Scalar >
Derived lsst::sphgeom::Interval< Derived, Scalar >::erodedBy ( Scalar  x) const
inline

Definition at line 240 of file Interval.h.

240 { return Interval(*this).erodeBy(x); }

◆ expandedTo() [1/2]

template<typename Derived , typename Scalar >
Derived lsst::sphgeom::Interval< Derived, Scalar >::expandedTo ( Interval< Derived, Scalar > const &  x) const
inline

expandedTo returns the smallest interval containing the union of this interval and x.

Definition at line 220 of file Interval.h.

220  {
221  return Interval(*this).expandTo(x);
222  }

◆ expandedTo() [2/2]

template<typename Derived , typename Scalar >
Derived lsst::sphgeom::Interval< Derived, Scalar >::expandedTo ( Scalar  x) const
inline

expandedTo returns the smallest interval containing the union of this interval and x.

Definition at line 218 of file Interval.h.

218 { return Interval(*this).expandTo(x); }

◆ expandTo() [1/2]

template<typename Derived , typename Scalar >
Interval& lsst::sphgeom::Interval< Derived, Scalar >::expandTo ( Interval< Derived, Scalar > const &  x)
inline

expandTo minimally expands this interval to contain x.

Definition at line 204 of file Interval.h.

204  {
205  if (isEmpty()) {
206  *this = x;
207  } else if (!x.isEmpty()) {
208  _a = std::min(_a, x._a);
209  _b = std::max(_b, x._b);
210  }
211  return *this;
212  }

◆ expandTo() [2/2]

template<typename Derived , typename Scalar >
Interval& lsst::sphgeom::Interval< Derived, Scalar >::expandTo ( Scalar  x)
inline

expandTo minimally expands this interval to contain x.

Definition at line 192 of file Interval.h.

192  {
193  if (isEmpty()) {
194  _a = x;
195  _b = x;
196  } else if (x < _a) {
197  _a = x;
198  } else if (x > _b) {
199  _b = x;
200  }
201  return *this;
202  }

◆ getA()

template<typename Derived , typename Scalar >
Scalar lsst::sphgeom::Interval< Derived, Scalar >::getA ( ) const
inline

getA returns the lower endpoint of this interval.

The return value for empty intervals is arbitrary.

Definition at line 76 of file Interval.h.

76 { return _a; }

◆ getB()

template<typename Derived , typename Scalar >
Scalar lsst::sphgeom::Interval< Derived, Scalar >::getB ( ) const
inline

getB returns the upper endpoint of this interval.

The return value for empty intervals is arbitrary.

Definition at line 80 of file Interval.h.

80 { return _b; }

◆ getCenter()

template<typename Derived , typename Scalar >
Scalar lsst::sphgeom::Interval< Derived, Scalar >::getCenter ( ) const
inline

getCenter returns the center of this interval.

It is arbitrary for empty intervals.

Definition at line 89 of file Interval.h.

89 { return 0.5 * (_a + _b); }

◆ getSize()

template<typename Derived , typename Scalar >
Scalar lsst::sphgeom::Interval< Derived, Scalar >::getSize ( ) const
inline

getSize returns the size (length, width) of this interval.

It is zero for single-point intervals, and NaN or negative for empty intervals.

Definition at line 93 of file Interval.h.

93 { return _b - _a; }

◆ intersects() [1/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::intersects ( Interval< Derived, Scalar > const &  x) const
inline

intersects returns true if the intersection of this interval and x is non-empty.

Definition at line 132 of file Interval.h.

132  {
133  return !isDisjointFrom(x);
134  }

◆ intersects() [2/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::intersects ( Scalar  x) const
inline

intersects returns true if the intersection of this interval and x is non-empty.

Definition at line 130 of file Interval.h.

130 { return _a <= x && x <= _b; }

◆ isDisjointFrom() [1/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::isDisjointFrom ( Interval< Derived, Scalar > const &  x) const
inline

isDisjointFrom returns true if the intersection of this interval and x is empty.

Definition at line 119 of file Interval.h.

119  {
120  if (isEmpty() || x.isEmpty()) {
121  return true;
122  }
123  return _a > x._b || _b < x._a;
124  }

◆ isDisjointFrom() [2/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::isDisjointFrom ( Scalar  x) const
inline

isDisjointFrom returns true if the intersection of this interval and x is empty.

Definition at line 115 of file Interval.h.

115  {
116  return !intersects(x);
117  }

◆ isEmpty()

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::isEmpty ( ) const
inline

isEmpty returns true if this interval does not contain any points.

Definition at line 83 of file Interval.h.

83  {
84  return !(_a <= _b); // returns true when _a and/or _b is NaN
85  }

◆ isWithin() [1/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::isWithin ( Interval< Derived, Scalar > const &  x) const
inline

isWithin returns true if the intersection of this interval and x is this interval.

Definition at line 144 of file Interval.h.

144  {
145  return x.contains(*this);
146  }

◆ isWithin() [2/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::isWithin ( Scalar  x) const
inline

isWithin returns true if the intersection of this interval and x is this interval.

Definition at line 140 of file Interval.h.

140  {
141  return (_a == x && _b == x) || isEmpty();
142  }

◆ operator!=() [1/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::operator!= ( Interval< Derived, Scalar > const &  i) const
inline

Definition at line 65 of file Interval.h.

65 { return !(*this == i); }

◆ operator!=() [2/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::operator!= ( Scalar  x) const
inline

Definition at line 72 of file Interval.h.

72 { return !(*this == x); }

◆ operator==() [1/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::operator== ( Interval< Derived, Scalar > const &  i) const
inline

Two closed intervals are equal if their endpoints are the same, or both are empty.

Definition at line 61 of file Interval.h.

61  {
62  return (_a == i._a && _b == i._b) || (i.isEmpty() && isEmpty());
63  }

◆ operator==() [2/2]

template<typename Derived , typename Scalar >
bool lsst::sphgeom::Interval< Derived, Scalar >::operator== ( Scalar  x) const
inline

A closed interval is equal to a point x if both endpoints equal x.

Definition at line 68 of file Interval.h.

68  {
69  return (_a == x && _b == x) || (x != x && isEmpty());
70  }

◆ relate() [1/2]

template<typename Derived , typename Scalar >
Relationship lsst::sphgeom::Interval< Derived, Scalar >::relate ( Interval< Derived, Scalar > const &  x) const

relate returns a bitset S describing the spatial relationships between this interval and x. For each relation that holds, the bitwise AND of S and the corresponding Relationship will be non-zero.

Definition at line 269 of file Interval.h.

271 {
272  if (isEmpty()) {
273  if (x.isEmpty()) {
274  return CONTAINS | DISJOINT | WITHIN;
275  }
276  return DISJOINT | WITHIN;
277  }
278  if (x.isEmpty()) {
279  return CONTAINS | DISJOINT;
280  }
281  if (_a == x._a && _b == x._b) {
282  return CONTAINS | WITHIN;
283  }
284  if (_a > x._b || _b < x._a) {
285  return DISJOINT;
286  }
287  if (_a <= x._a && _b >= x._b) {
288  return CONTAINS;
289  }
290  if (x._a <= _a && x._b >= _b) {
291  return WITHIN;
292  }
293  return INTERSECTS;
294 }

◆ relate() [2/2]

template<typename Derived , typename Scalar >
Relationship lsst::sphgeom::Interval< Derived, Scalar >::relate ( Scalar  x) const

relate returns a bitset S describing the spatial relationships between this interval and x. For each relation that holds, the bitwise AND of S and the corresponding Relationship will be non-zero.

Definition at line 249 of file Interval.h.

249  {
250  if (isEmpty()) {
251  if (x != x) {
252  return CONTAINS | DISJOINT | WITHIN;
253  }
254  return DISJOINT | WITHIN;
255  }
256  if (x != x) {
257  return CONTAINS | DISJOINT;
258  }
259  if (_a == x && _b == x) {
260  return CONTAINS | WITHIN;
261  }
262  if (intersects(x)) {
263  return CONTAINS;
264  }
265  return DISJOINT;
266 }

The documentation for this class was generated from the following file:
y
int y
Definition: SpanSet.cc:49
lsst::sphgeom::Interval::isEmpty
bool isEmpty() const
isEmpty returns true if this interval does not contain any points.
Definition: Interval.h:83
lsst::sphgeom::Interval::Interval
Interval()
This constructor creates an empty interval.
Definition: Interval.h:51
x
double x
Definition: ChebyshevBoundedField.cc:277
lsst::sphgeom::Interval::isDisjointFrom
bool isDisjointFrom(Scalar x) const
Definition: Interval.h:115
std::min
T min(T... args)
lsst::sphgeom::Interval::dilateBy
Interval & dilateBy(Scalar x)
For positive x, dilateBy morphologically dilates this interval by [-x,x], which is equivalent to the ...
Definition: Interval.h:230
std::max
T max(T... args)
lsst::sphgeom::Interval::intersects
bool intersects(Scalar x) const
Definition: Interval.h:130