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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <vespa/searchlib/fef/blueprint.h>
#include <vespa/searchlib/util/random_normal.h>
namespace search::features {
/**
* Implements the executor for the random normal feature outputting a
* random number drawn from the Gaussian distribution with the
* two arguments 'mean' and 'stddev'.
* The same hit always returns the same random number.
**/
class RandomNormalStableExecutor : public fef::FeatureExecutor {
private:
RandomNormal _rnd; // seeded once per match
uint64_t _seed;
public:
RandomNormalStableExecutor(uint64_t seed, double mean, double stddev);
void execute(uint32_t docId) override;
};
/**
* Implements the blueprint for the random normal stable feature.
*/
class RandomNormalStableBlueprint : public fef::Blueprint {
private:
uint64_t _seed;
double _mean;
double _stddev;
public:
RandomNormalStableBlueprint();
void visitDumpFeatures(const fef::IIndexEnvironment & env, fef::IDumpFeatureVisitor & visitor) const override;
fef::Blueprint::UP createInstance() const override;
fef::ParameterDescriptions getDescriptions() const override {
return fef::ParameterDescriptions().
// Can run without parameters:
desc().
// Can run with two parameters (mean and stddev):
desc().
number(). // mean
number(). // stddev
// Can run with three parameters:
desc().
number(). // mean
number(). // stddev
string(); // in order to name different features
}
bool setup(const fef::IIndexEnvironment & env, const fef::ParameterList & params) override;
fef::FeatureExecutor &createExecutor(const fef::IQueryEnvironment &env, vespalib::Stash &stash) const override;
};
}
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