#include <VSelector.h>
Public Types | |
| typedef vector< WeightType > | WeightVector |
| A vector of weights. | |
| typedef WeightVector::const_iterator | WIterator |
| The weight vector iterator type. | |
| typedef vector< T > | ObjectVector |
| A vector ob objects. | |
| typedef ObjectVector::iterator | iterator |
| The object vector iterator type. | |
| typedef ObjectVector::const_iterator | const_iterator |
| The object vector const iterator type. | |
| typedef ObjectVector::size_type | size_type |
| Size type of the underlying vector. | |
Public Member Functions | |
| VSelector (size_type reserved=0) | |
| Default constructor. | |
| void | swap (VSelector &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, const T &) |
| Reweight an object previously inserted giving it a new weight. | |
| WeightType | erase (const T &) |
| Erase an object, previously inserted. | |
| void | replace (const T &told, const T &tnew) |
| Replace all occurencies of told with tnew 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 vector of objects. | |
| const_iterator | end () const |
Access to the end() iterator in the underlying vector of objects. | |
| bool | empty () const |
| Returns true if the VSelector is empty. | |
| size_type | size () const |
| Returns the number of objects in the selector. | |
| void | reserve (size_type reserved) |
| Allocate space for a number of objects in the underlying vectors. | |
| 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. | |
Protected Member Functions | |
| size_type | iselect (double rnd, double *remainder) const throw (range_error) |
| Internal selection engine. | |
Private Attributes | |
| WeightVector | theSums |
| The vector of accumulated weights for the objects in the selector. | |
| WeightVector | theWeights |
| The vector of weights for the objects in the selector. | |
| ObjectVector | theObjects |
| The vector of objects in the selector. | |
| WeightType | theSum |
| The sum of all weights. | |
Internally, the objects of class T are stored in a vector parallel to a vector of the probability of the corresponding object plus the accumulated sum of probabilities of all objects before the current one in the vector. 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.
VSelector<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 VSelector.h.
| typedef vector<WeightType> ThePEG::VSelector< T, WeightType >::WeightVector |
| typedef WeightVector::const_iterator ThePEG::VSelector< T, WeightType >::WIterator |
| typedef vector<T> ThePEG::VSelector< T, WeightType >::ObjectVector |
| typedef ObjectVector::iterator ThePEG::VSelector< T, WeightType >::iterator |
| typedef ObjectVector::const_iterator ThePEG::VSelector< T, WeightType >::const_iterator |
| typedef ObjectVector::size_type ThePEG::VSelector< T, WeightType >::size_type |
| WeightType ThePEG::VSelector< 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 is returned.
Definition at line 94 of file VSelector.h.
| WeightType ThePEG::VSelector< T, WeightType >::reweight | ( | WeightType | , | |
| const T & | ||||
| ) |
Reweight an object previously inserted giving it a new weight.
If several equivalent objects exists, all of them will be reweighted.
| WeightType ThePEG::VSelector< 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 probabilities is returned.
| T& ThePEG::VSelector< T, WeightType >::select | ( | double | rnd, | |
| double * | remainder = 0 | |||
| ) | throw (range_error) [inline] |
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. |
Definition at line 138 of file VSelector.h.
Referenced by ThePEG::VSelector< pair< int, int > >::operator[](), and ThePEG::VSelector< pair< int, int > >::select().
| T& ThePEG::VSelector< 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 149 of file VSelector.h.
| const T& ThePEG::VSelector< T, WeightType >::select | ( | double | rnd, | |
| double * | remainder = 0 | |||
| ) | 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.
| 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. |
Definition at line 164 of file VSelector.h.
| const T& ThePEG::VSelector< 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 175 of file VSelector.h.
| T& ThePEG::VSelector< 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 192 of file VSelector.h.
| const T& ThePEG::VSelector< 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 212 of file VSelector.h.
| WeightType ThePEG::VSelector< 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 225 of file VSelector.h.
1.5.5