39 lines
1.0 KiB
C++
39 lines
1.0 KiB
C++
/*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* Copyright 2016-2019 Danny Robson <danny@nerdcruft.net>
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*/
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#pragma once
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#include "../std.hpp"
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#include <cstdint>
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#include <limits>
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namespace cruft::rand {
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// multiply-with-carry style generator suitable for rapid seeking and
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// GPU generation.
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//
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// as with all such style generators, the seed value is very important.
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// don't allow either half of the uint64_t to be zero.
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struct mwc64x {
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public:
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using result_type = u32;
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using seed_type = u64;
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explicit mwc64x (seed_type);
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result_type operator() (void);
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static constexpr auto max (void) noexcept { return std::numeric_limits<result_type>::max (); }
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static constexpr auto min (void) noexcept { return std::numeric_limits<result_type>::min (); }
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private:
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uint64_t m_state;
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};
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}
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