random.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
 *                                                                           *
 * Copyright(C) 2021-2025                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
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 * All rights reserved.                                                      *
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 * This program is free software; you can redistribute it and/or modify      *
 * it under the terms of the Mozilla Public License Version 2.0 as published *
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 * This program is distributed in the hope that it will be useful,           *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              *
 * Mozilla Public License Version 2.0                                        *
 * (https://www.mozilla.org/en-US/MPL/2.0/) for more details.                *
 ****************************************************************************/
 
#ifndef VCL_BASE_RANDOM_H
#define VCL_BASE_RANDOM_H
 
#include <vclib/base/concepts/range.h>
 
#include <algorithm>
#include <optional>
#include <random>
 
namespace vcl {
 
inline std::mt19937 randomGenerator(std::optional<uint> seed = std::nullopt)
{
    std::mt19937 gen;
 
    if (seed.has_value()) {
        gen.seed(seed.value());
    } else {
        std::random_device rd;
        gen.seed(rd()); // random seed
    }
 
    return gen;
}
 
template<Range R>
void shuffle(R&& range, std::optional<uint> seed = std::nullopt)
{
    std::mt19937 generator = randomGenerator(seed);
 
    std::shuffle(range.begin(), range.end(), generator);
}
 
} // namespace vcl
 
#endif // VCL_BASE_RANDOM_H