mt19937_rng.h

/*******************************************************************************
 * Copyright 2020-2022 MINRES Technologies GmbH
 *
 * 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.
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#ifndef _UTIL_MT19937_RNG_H_
#define _UTIL_MT19937_RNG_H_
 
#include <cassert>
#include <iostream>
#include <random>

namespace util {
class MT19937 {
public:
    static void seed(uint64_t new_seed = std::mt19937_64::default_seed) { inst().seed(new_seed); }
    static uint64_t uniform() {
        std::uniform_int_distribution<uint64_t> u;
        return u(inst());
    }

    template <typename T> static T uniform() {
        std::uniform_int_distribution<T> u;
        return u(inst());
    }

    static uint64_t uniform(uint64_t min, uint64_t max) {
        assert(min < max);
        std::uniform_int_distribution<uint64_t> u(min, max);
        return u(inst());
    }

    static double normal() {
        std::normal_distribution<> u;
        return u(inst());
    }

    static double lognormal() {
        std::lognormal_distribution<> u;
        return u(inst());
    }
 
private:
    static std::mt19937_64& inst() {
        static thread_local std::mt19937_64 rng;
        return rng;
    }
};
} // namespace util
#endif /* _UTIL_MT19937_RNG_H_ */