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Dynamic Random Variates ( dynamic_random_variate )


An instance R of the data type dynamic_random_variate is a non-uniform random number generator. The generation process is governed by an array<int> w. Let [l..r] be the index range of w and let W = $\sum_{i}^{}$w[i] be the total weight. Then any integer i $\in$ [l..h] is generated with probability w[i]/W. The weight function w must be non-negative and W must be non-zero. The weight function can be changed dynamically.

#include < LEDA/core/random_variate.h >


dynamic_random_variate R(const array<int>& w) creates an instance R of type dynamic_random_variate.


int R.generate() generates i $\in$ [l..h] with probability w[i]/W.

int R.set_weight(int i, int g)
    sets w[i] to g and returns the old value of w[i].
Precondition i $\in$ [l..h].