44 lines
1.2 KiB
C++
44 lines
1.2 KiB
C++
|
/*
|
||
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
* you may not use this file except in compliance with the License.
|
||
|
|
* You may obtain a copy of the License at
|
||
|
|
*
|
||
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
*
|
||
|
|
* Unless required by applicable law or agreed to in writing, software
|
||
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
* See the License for the specific language governing permissions and
|
||
|
|
* limitations under the License.
|
||
|
|
*
|
||
|
|
* Copyright 2016 Danny Robson <danny@nerdcruft.net>
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef __UTIL_RAND_MWC64X_HPP
|
||
|
|
#define __UTIL_RAND_MWC64X_HPP
|
||
|
|
|
||
|
|
#include <cstdint>
|
||
|
|
|
||
|
|
namespace util { namespace rand {
|
||
|
|
// multiply-with-carry style generator suitable for rapid seeking and
|
||
|
|
// GPU generation.
|
||
|
|
//
|
||
|
|
// as with all such style generators, the seed value is very important.
|
||
|
|
// don't allow either half of the uint64_t to be zero.
|
||
|
|
struct mwc64x {
|
||
|
|
public:
|
||
|
|
using value_type = uint32_t;
|
||
|
|
using seed_type = uint64_t;
|
||
|
|
|
||
|
|
mwc64x (seed_type);
|
||
|
|
|
||
|
|
value_type operator() (void);
|
||
|
|
|
||
|
|
private:
|
||
|
|
uint64_t m_state;
|
||
|
|
};
|
||
|
|
} }
|
||
|
|
|
||
|
|
|
||
|
|
#endif
|