#include <Selector.h>
Public Types | |
| typedef map< WeightType, T, less< WeightType > > | MapType |
| Map doubles to objects. | |
| typedef MapType::const_iterator | const_iterator |
| Iterator corresponding to the underlying map. | |
| typedef MapType::iterator | iterator |
| Iterator corresponding to the underlying map. | |
| typedef MapType::size_type | size_type |
| Size type of the underlying map. | |
Public Member Functions | |
| Selector () | |
| Default constructor. | |
| void | swap (Selector &s) |
| Swap the underlying representation with the argument. | |
| WeightType | insert (WeightType d, const T &t) |
| Insert an object given a probability for this object. | |
| WeightType | reweight (WeightType d, const T &t) |
| Reweight an object previously inserted giving it a new weight. | |
| WeightType | erase (const T &) |
| Erase an object, previously inserted. | |
| void | replace (const T &oldObject, const T &newObject) |
| Replace all occurencies of oldObject with newObject without changing the probability for the entry. | |
| T & | select (double rnd, double *remainder=0) throw (range_error) |
| Select an object randomly. | |
| T & | operator[] (double rnd) throw (range_error) |
| Selct an object randomly. | |
| const T & | select (double rnd, double *remainder=0) const throw (range_error) |
| Selct an object randomly. | |
| const T & | operator[] (double rnd) const throw (range_error) |
| Selct an object randomly. | |
| template<typename RNDGEN> | |
| T & | select (RNDGEN &rnd) throw (range_error) |
| Selct an object randomly. | |
| template<typename RNDGEN> | |
| const T & | select (RNDGEN &rnd) const throw (range_error) |
| Selct an object randomly. | |
| WeightType | sum () const |
| Return the sum of probabilities of the objects inserted. | |
| const_iterator | begin () const |
Access to the begin() iterator of the underlying map. | |
| const_iterator | end () const |
Access to the end() iterator in the underlying map. | |
| bool | empty () const |
| Returns true if the Selector is empty. | |
| size_type | size () const |
| Returns the number of objects in the selector. | |
| void | clear () |
| Erases all objects. | |
| template<typename OStream> | |
| void | output (OStream &) const |
| Output to a stream. | |
| template<typename IStream> | |
| void | input (IStream &) |
| Input from a stream. | |
Private Attributes | |
| MapType | theMap |
| The underlying map relating sums of probabilities to inserted objects. | |
| WeightType | theSum |
| The sum of all probabilities assicialted with inserted objects. | |
Internally, the objects of class T are stored in a map where the key is the probability of the corresponding object plus the accumulated sum of probabilities of all objects before the current one in the map. This allows for fast retreival of an object according to its probability. Where fast means that the time increases as a logarithm of the number of objects in the selector.
Here is an example on how to use the class:
double random(); // A random generator returning a number between 0 and 1.
class foo; // Any class.
Selector<foo*> bar; // A selector.
foo f1, f2;
bar.insert(0.5,&f1) // assign probability 0.5
bar.insert(0.5,&f2) // to each of f1 and f2
foo * f = bar.select(random()) // randomly returns a pointer to f1 or f2
Definition at line 46 of file Selector.h.
| typedef map<WeightType, T, less<WeightType> > ThePEG::Selector< T, WeightType >::MapType |
| typedef MapType::const_iterator ThePEG::Selector< T, WeightType >::const_iterator |
| typedef MapType::iterator ThePEG::Selector< T, WeightType >::iterator |
| typedef MapType::size_type ThePEG::Selector< T, WeightType >::size_type |
| WeightType ThePEG::Selector< T, WeightType >::insert | ( | WeightType | d, | |
| const T & | t | |||
| ) | [inline] |
Insert an object given a probability for this object.
If the probability is zero or negative, the object will not be inserted and the probability itself is returned. Otherwise the sum of probabilities so far is returned.
Definition at line 84 of file Selector.h.
Referenced by ThePEG::Selector< ThePEG::Pointer::TransientRCPtr >::reweight().
| WeightType ThePEG::Selector< T, WeightType >::reweight | ( | WeightType | d, | |
| const T & | t | |||
| ) | [inline] |
Reweight an object previously inserted giving it a new weight.
Semantically reweight(w,o); is equivalent to erase(o); insert(w,o);
Definition at line 97 of file Selector.h.
| WeightType ThePEG::Selector< T, WeightType >::erase | ( | const T & | ) |
Erase an object, previously inserted.
If the object had not been inserted, nothing will happen. If several copies of the object has been inserted, all will be removed removed. In all cases the sum of the remaining probabilities is returned.
Referenced by ThePEG::Selector< ThePEG::Pointer::TransientRCPtr >::reweight().
| T& ThePEG::Selector< T, WeightType >::select | ( | double | rnd, | |
| double * | remainder = 0 | |||
| ) | throw (range_error) |
Select an object randomly.
Given a random number flatly distributed in the interval ]0,1[ Select an object according to the individual probabilities specified when they were inserted. If rnd <= 0 or if rnd >= 1 or the Selector is empty, a range_error will be thrown.
| rnd | a flat random number in the interval ]0,1[ | |
| remainder | if non-zero the double pointed to will be set to a uniform random number in the interval ]0,1[ calculated from the fraction of rnd which was in the range of the selected object. |
Referenced by ThePEG::Selector< ThePEG::Pointer::TransientRCPtr >::operator[](), and ThePEG::Selector< ThePEG::Pointer::TransientRCPtr >::select().
| T& ThePEG::Selector< T, WeightType >::operator[] | ( | double | rnd | ) | throw (range_error) [inline] |
Selct an object randomly.
Given a random number flatly distributed in the interval ]0,1[ Select an object according to the individual probabilities specified when they were inserted. If rnd <= 0 or if rnd >= 1 or the Selector is empty, a range_error will be thrown.
Definition at line 140 of file Selector.h.
| const T& ThePEG::Selector< T, WeightType >::select | ( | double | rnd, | |
| double * | remainder = 0 | |||
| ) | const throw (range_error) |
Selct an object randomly.
Given a random number flatly distributed in the interval ]0,1[ Select an object according to the individual probabilities specified when they were inserted. If rnd <= 0 or if rnd >= 1 or the Selector is empty, a range_error will be thrown.
| rnd | a flat random number in the interval ]0,1[ | |
| remainder | if non-zero the double pointed to will be set to a uniform random number in the interval ]0,1[ calculated from the fraction of rnd which was in the range of the selected object. |
| const T& ThePEG::Selector< T, WeightType >::operator[] | ( | double | rnd | ) | const throw (range_error) [inline] |
Selct an object randomly.
Given a random number flatly distributed in the interval ]0,1[ select an object according to the individual probabilities specified when they were inserted. If rnd <= 0 or if rnd >= 1 or the Selector is empty, a range_error will be thrown.
Definition at line 162 of file Selector.h.
| T& ThePEG::Selector< T, WeightType >::select | ( | RNDGEN & | rnd | ) | throw (range_error) [inline] |
Selct an object randomly.
Given a random number generator which generates flat random numbers in the interval ]0,1[ with the operator()() function, select an object according to the individual probabilities specified when they were inserted. If the generated number is outside the allowed range or the Selector is empty, a range_error will be thrown. The generator should have a push_back function which will be used push back a uniform random number in the interval ]0,1[ calculated from the fraction of rnd which was in the range of the selected object.
Definition at line 177 of file Selector.h.
| const T& ThePEG::Selector< T, WeightType >::select | ( | RNDGEN & | rnd | ) | const throw (range_error) [inline] |
Selct an object randomly.
Given a random number generator which generates flat random numbers in the interval ]0,1[ with the operator()() function, select an object according to the individual probabilities specified when they were inserted. If the generated number is outside the allowed range or the Selector is empty, a range_error will be thrown. The generator should have a push_back function which will be used push back a uniform random number in the interval ]0,1[ calculated from the fraction of rnd which was in the range of the selected object.
Definition at line 197 of file Selector.h.
| WeightType ThePEG::Selector< T, WeightType >::sum | ( | ) | const [inline] |
Return the sum of probabilities of the objects inserted.
Note that probabilities specified when objects are inserted are rescaled with this number to give unit probability for 'select()'.
Definition at line 210 of file Selector.h.
| const_iterator ThePEG::Selector< T, WeightType >::begin | ( | ) | const [inline] |
Access to the begin() iterator of the underlying map.
Dereferenced, it will give a std::pair<WeightType, T>, where 'first' is the sum of all probabilities up to this one, and 'second' is the object inserted.
Definition at line 218 of file Selector.h.
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