weighted_pick() [2/2]

static size_t MayaFlux::Kinesis::Stochastic::Weights::weighted_pick ( std::span< const double >  weights, Stochastic &  generator  )

inlinestatic

Weighted random draw over a row of nonnegative weights.

Parameters

weights	Row to draw from. Negative entries are treated as zero.
generator	Entropy source for the draw

Returns

Index into weights, or weights.size() when every weight is zero or negative and no draw is possible

Does not require a Weights instance or normalized weights; any span of nonnegative values is a valid distribution to draw from.

Definition at line 252 of file Weights.hpp.

    {
        double total = 0.0;
        for (double weight : weights) {
            total += std::max(0.0, weight);
        }
 
        if (total <= 0.0) {
            return weights.size();
        }
 
        const double target = generator(0.0, total);
        double running = 0.0;
        for (size_t i = 0; i < weights.size(); ++i) {
            running += std::max(0.0, weights[i]);
            if (target <= running) {
                return i;
            }
        }
        return weights.size() - 1;
    }

References total, and weight.

Referenced by MayaFlux::Nodes::Network::WalkOperator::advance(), and weighted_pick().

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