// Copyright 2018 Google LLC

//

// 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 "cc/random.h"

#include <array>

#include <algorithm>

#include <functional>

#include "gtest/gtest.h"

namespace minigo {

namespace {

TEST(RandomTest, TestUniformArray) {

Random rnd(66);

std::array<float, 100> sum;

for (auto& s : sum) {

s = 0;

}

for (int iter = 0; iter < 10000; ++iter) {

std::array<float, 100> samples;

rnd.Uniform(5, 10, &samples);

for (int i = 0; i < 100; ++i) {

sum[i] += samples[i];

}

}

std::array<float, 100> avg;

for (int i = 0; i < 100; ++i) {

avg[i] = sum[i] / 10000;

}

for (const auto& a : avg) {

EXPECT_NEAR(7.5, a, 0.05);

}

}

TEST(RandomTest, TestOperator) {

Random rnd(42);

float sum = 0;

for (int iter = 0; iter < 10000; ++iter) {

sum += rnd();

}

float avg = sum / 10000;

EXPECT_NEAR(0.5, avg, 0.01);

}

TEST(RandomTest, Dirichlet) {

Random rnd(777);

std::array<float, 40> sum;

for (auto& s : sum) {

s = 0;

}

for (int iter = 0; iter < 10000; ++iter) {

std::array<float, 40> samples;

rnd.Dirichlet(0.03, &samples);

std::sort(samples.begin(), samples.end(), std::greater<float>());

for (int i = 0; i < 40; ++i) {

sum[i] += samples[i];

}

}

std::array<float, 40> avg;

for (int i = 0; i < 40; ++i) {

avg[i] = sum[i] / 10000;

}

EXPECT_NEAR(0.60, avg[0], 0.01);

EXPECT_NEAR(0.21, avg[1], 0.01);

EXPECT_NEAR(0.09, avg[2], 0.01);

EXPECT_NEAR(0.05, avg[3], 0.01);

EXPECT_NEAR(0.02, avg[4], 0.01);

EXPECT_NEAR(0.01, avg[5], 0.01);

for (int i = 6; i < 40; ++i) {

EXPECT_NEAR(0, avg[i], 0.01);

}

}

} // namespace

} // namespace minigo