44 lines
1.2 KiB
C++
44 lines
1.2 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2016 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_RAND_MWC64X_HPP
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#define __UTIL_RAND_MWC64X_HPP
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#include <cstdint>
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namespace util::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 value_type = uint32_t;
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using seed_type = uint64_t;
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explicit mwc64x (seed_type);
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value_type operator() (void);
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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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#endif
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