/*

* Copyright (C) 2020-2026 MEmilio

*

* Authors: Daniel Abele

*

* Contact: Martin J. Kuehn <[email protected]>

*

* 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.

*/

#include "memilio/utils/random_number_generator.h"

#include "gmock/gmock.h"

#include "gtest/gtest.h"

#include <algorithm>

#include <cstdint>

#include <iterator>

TEST(RandomNumberGenerator, counter)

{

mio::RandomNumberGenerator rng;

uint64_t n = 10;

for (auto i = uint64_t(0); i < n; ++i) {

rng();

}

ASSERT_EQ(rng.get_counter(), mio::Counter<uint64_t>(n)); //counter was incremented

auto s1 = rng();

for (auto i = uint64_t(0); i < n; ++i) {

rng();

}

ASSERT_EQ(rng.get_counter(), mio::Counter<uint64_t>(2 * n + 1)); //counter was further incremented

rng.set_counter(mio::Counter<uint64_t>{n});

ASSERT_EQ(rng.get_counter(), mio::Counter<uint64_t>(n)); //counter was reverted

auto s2 = rng();

ASSERT_EQ(s1, s2);

}

TEST(RandomNumberGenerator, subsequences)

{

uint32_t subsequence_index{5};

mio::Counter<uint32_t> subsequence_counter{12};

auto counter = mio::rng_totalsequence_counter<uint64_t>(subsequence_index, subsequence_counter);

ASSERT_EQ(counter, mio::Counter<uint64_t>{5 * 4'294'967'296ll + 12});

auto subsequence_counter2 = mio::rng_subsequence_counter<uint32_t>(counter);

ASSERT_EQ(subsequence_counter2, subsequence_counter);

}

TEST(TestDiscreteDistribution, generate)

{

auto distribution = mio::DiscreteDistributionInPlace<size_t>();

auto rng = mio::RandomNumberGenerator();

std::vector<double> weights;

for (size_t i = 0; i < 50; i++) {

weights = {};

ASSERT_EQ(distribution(rng, {weights}), 0);

weights = {0.5};

ASSERT_EQ(distribution(rng, {weights}), 0);

weights = {0.5, 1.3, 0.1, 0.4, 0.3};

auto d = distribution(rng, {weights});

ASSERT_GE(d, 0);

ASSERT_LE(d, 4);

}

}