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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <cstddef>
namespace search::queryeval {
// Model how boolean result decisions flow through intermediate nodes
// of different types based on relative estimates for sub-expressions
class AndFlow {
private:
double _flow;
size_t _cnt;
public:
AndFlow(double in = 1.0) noexcept : _flow(in), _cnt(0) {}
void add(double est) noexcept {
_flow *= est;
++_cnt;
}
double flow() const noexcept {
return _flow;
}
double estimate() const noexcept {
return (_cnt > 0) ? _flow : 0.0;
}
};
class OrFlow {
private:
double _flow;
public:
OrFlow(double in = 1.0) noexcept : _flow(in) {}
void add(double est) noexcept {
_flow *= (1.0 - est);
}
double flow() const noexcept {
return _flow;
}
double estimate() const noexcept {
return (1.0 - _flow);
}
};
class AndNotFlow {
private:
double _flow;
size_t _cnt;
public:
AndNotFlow(double in = 1.0) noexcept : _flow(in), _cnt(0) {}
void add(double est) noexcept {
_flow *= (_cnt++ == 0) ? est : (1.0 - est);
}
double flow() const noexcept {
return _flow;
}
double estimate() const noexcept {
return (_cnt > 0) ? _flow : 0.0;
}
};
}
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