random_number_generator.cpp

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/*
 *  SPDX-FileCopyrightText: Copyright 2021, Siavash Ameli <sameli@berkeley.edu>
 *  SPDX-License-Identifier: BSD-3-Clause
 *  SPDX-FileType: SOURCE
 *
 *  This program is free software: you can redistribute it and/or modify it
 *  under the terms of the license found in the LICENSE.txt file in the root
 *  directory of this source tree.
 */
 
 
// =======
// Headers
// =======
 
#include "./random_number_generator.h"
#include <cassert>  // assert
#include <cstdlib>  // NULL
#include "./xoshiro_256_star_star.h"  // Xoshiro256StarStar
 
 
// =============
// Constructor 1
// =============
 
 
RandomNumberGenerator::RandomNumberGenerator():
    num_threads(1)
{
    int64_t seed = -1;  // Negative indicates using processor time as seed
    this->initialize(seed);
}
 
 
// =============
// Constructor 2
// =============
 
 
RandomNumberGenerator::RandomNumberGenerator(const int num_threads_):
    num_threads(num_threads_)
{
    int64_t seed = -1;  // Negative indicates using processor time as seed
    this->initialize(seed);
}
 
 
// =============
// Constructor 3
// =============
 
 
RandomNumberGenerator::RandomNumberGenerator(
        const int num_threads_,
        const int64_t seed):
    num_threads(num_threads_)
{
    this->initialize(seed);
}
 
 
// ==========
// Destructor
// ==========
 
 
RandomNumberGenerator::~RandomNumberGenerator()
{
    if (this->xoshiro_256_star_star != NULL)
    {
        for (int thread_id=0; thread_id < this->num_threads; ++thread_id)
        {
            delete this->xoshiro_256_star_star[thread_id];
            this->xoshiro_256_star_star[thread_id] = NULL;
        }
 
        delete[] this->xoshiro_256_star_star;
        this->xoshiro_256_star_star = NULL;
    }
}
 
 
// ==========
// initialize
// ==========
 
 
void RandomNumberGenerator::initialize(int64_t seed)
{
    assert(this->num_threads > 0);
 
    this->xoshiro_256_star_star = new Xoshiro256StarStar*[this->num_threads];
 
    for (int thread_id=0; thread_id < this->num_threads; ++thread_id)
    {
        this->xoshiro_256_star_star[thread_id] = new Xoshiro256StarStar(seed);
 
        // Repeate jump j times to have different initial state for each thread
        // This is the main purpose of this class.
        for (int j=0; j < thread_id+1; ++j)
        {
            this->xoshiro_256_star_star[thread_id]->jump();
        }
    }
}
 
 
// ====
// next
// ====
 
 
uint64_t RandomNumberGenerator::next(const int thread_id)
{
    return this->xoshiro_256_star_star[thread_id]->next();
}