framework/delibs/decpp/deRandom.cpp

/*-------------------------------------------------------------------------
 * drawElements C++ Base Library
 * -----------------------------
 *
 * Copyright 2014 The Android Open Source Project
 *
 * 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.
 *
 *//*!
 * \file
 * \brief Random number generator utilities.
 *//*--------------------------------------------------------------------*/

#include "deRandom.hpp"

inline bool operator== (const deRandom& a, const deRandom& b)
{
	return a.x == b.x && a.y == b.y && a.z == b.z && a.w == b.w;
}

inline bool operator!= (const deRandom& a, const deRandom& b)
{
	return a.x != b.x || a.y != b.y || a.z != b.z || a.w != b.w;
}

namespace de
{

bool Random::operator== (const Random& other) const
{
	return m_rnd == other.m_rnd;
}

bool Random::operator!= (const Random& other) const
{
	return m_rnd != other.m_rnd;
}

void Random_selfTest (void)
{
	// getBool()

	{
		static const bool expected[] = { true, false, false, false, true, true, false, false, false, false, false, false, true, false, true, false, false, false, false, true };
		Random rnd(4789);
		for (int i = 0; i < DE_LENGTH_OF_ARRAY(expected); i++)
			DE_TEST_ASSERT(expected[i] == rnd.getBool());
	}

	// getInt(a, b)

	{
		static const int expected[] = { -6628, -6483, 802, -7758, -8463, 3165, 9216, 3107, 1851, 8707 };
		Random rnd(4789);
		for (int i = 0; i < DE_LENGTH_OF_ARRAY(expected); i++)
			DE_TEST_ASSERT(expected[i] == rnd.getInt(-10000, 10000));
	}

	// getUint32()

	{
		static const deUint32 expected[] = { 3694588092u, 3135240271u, 882874943u, 2108407657u, 376640368u, 1395362929u, 2611849801u, 3151830690u, 901476922u, 989608184u };
		Random rnd(4789);
		for (int i = 0; i < DE_LENGTH_OF_ARRAY(expected); i++)
			DE_TEST_ASSERT(expected[i] == rnd.getUint32());
	}

	// getUint64()

	{
		static const deUint64 expected[] = { 15868135030466279503ull, 3791919008751271785ull, 1617658064308767857ull, 11217809480510938786ull, 3871813899078351096ull, 14768747990643252542ull, 8163484985646009214ull, 14928018127607458387ull, 432108271545246292ull, 7318152987070448462ull };
		Random rnd(4789);
		for (int i = 0; i < DE_LENGTH_OF_ARRAY(expected); i++)
			DE_TEST_ASSERT(expected[i] == rnd.getUint64());
	}

	// getFloat()

	{
		static const float	expected[]	= { 0.763413f, 0.679680f, 0.288965f, 0.854431f, 0.403095f, 0.198132f, 0.729899f, 0.741484f, 0.358263f, 0.686578f };
		const float			epsilon		= 0.01f;
		Random rnd(4789);
		for (int i = 0; i < DE_LENGTH_OF_ARRAY(expected); i++)
			DE_TEST_ASSERT(de::abs(expected[i] - rnd.getFloat()) < epsilon);
	}

	// getFloat(a, b)

	{
		static const float	expected[] = { 824.996643f, 675.039185f, -24.691774f, 987.999756f, 179.702286f, -187.365463f, 764.975647f, 785.724182f, 99.413582f, 687.392151f };
		const float			epsilon		= 0.01f;
		Random rnd(4789);
		for (int i = 0; i < DE_LENGTH_OF_ARRAY(expected); i++)
			DE_TEST_ASSERT(de::abs(expected[i] - rnd.getFloat(-542.2f, 1248.7f)) < epsilon);
	}

	// choose(first, last, resultOut, num)

	{
		static const int	items[]						= { 3, 42, 45, 123, 654, -123, -90, 0, 43 };
		const int			numItemsPicked				= 5;
		static const int	expected[][numItemsPicked]	=
		{
			{ -123, 42, -90, 123, 43 },
			{ 43, 0, -90, 123, -123	},
			{ 3, 42, 45, 123, 0 },
			{ 3, 42, 45, -123, 654 },
			{ 3, 43, 45, -90, -123 },
			{ -90, 0, 45, -123, 654 },
			{ 3, 42, 43, 123, -123 },
			{ -90, 43, 45, 123, 654 },
			{ 0, 42, 45, 123, 654 },
			{ 0, -90, 45, -123, 654 }
		};
		Random rnd(4789);

		for (int i = 0; i < DE_LENGTH_OF_ARRAY(expected); i++)
		{
			int itemsDst[numItemsPicked];
			rnd.choose(DE_ARRAY_BEGIN(items), DE_ARRAY_END(items), &itemsDst[0], numItemsPicked);
			for (int j = 0; j < numItemsPicked; j++)
				DE_TEST_ASSERT(expected[i][j] == itemsDst[j]);
		}
	}

	// choose(first, last)

	{
		static const int items[]		= { 3, 42, 45, 123, 654, -123, -90, 0, 43 };
		static const int expected[]		= { 43, 123, -90, -90, 0, 3, 43, 0, 654, 43 };
		Random rnd(4789);

		for (int i = 0; i < DE_LENGTH_OF_ARRAY(expected); i++)
			DE_TEST_ASSERT(expected[i] == rnd.choose<int>(DE_ARRAY_BEGIN(items), DE_ARRAY_END(items)));
	}

	// chooseWeighted(first, last, weights)

	{
		static const int	items[]		= { 3,		42,		45,		123,	654,	-123,	-90,	0 };
		static const float	weights[]	= { 0.4f,	0.6f,	1.5f,	0.5f,	1.2f,	0.3f,	0.2f,	1.4f };
		DE_STATIC_ASSERT(DE_LENGTH_OF_ARRAY(items) == DE_LENGTH_OF_ARRAY(weights));
		static const int	expected[]	= { -90, 654, 45, 0, 45, 45, -123, -90, 45, 654 };
		Random rnd(4789);

		for (int i = 0; i < DE_LENGTH_OF_ARRAY(expected); i++)
			DE_TEST_ASSERT(expected[i] == rnd.chooseWeighted<int>(DE_ARRAY_BEGIN(items), DE_ARRAY_END(items), &weights[0]));
	}

	// suffle()

	{
		int					items[]									= { 3, 42, 45, 123, 654, -123, -90, 0, 43 };
		static const int	expected[][DE_LENGTH_OF_ARRAY(items)]	=
		{
			{ 45, 43, 654, -123, 123, 42, -90, 0, 3 },
			{ 0, 43, 3, 42, -123, -90, 654, 45, 123 },
			{ 42, 43, 654, 3, 0, 123, -90, -123, 45 },
			{ 3, 45, 43, 42, 123, 654, 0, -90, -123 },
			{ 42, 45, -123, 0, -90, 654, 3, 123, 43 },
			{ 654, -123, 3, 42, 43, 0, -90, 123, 45 },
			{ 0, 3, 654, 42, -90, 45, -123, 123, 43 },
			{ 654, 3, 45, 42, -123, -90, 123, 43, 0 },
			{ -90, 123, 43, 654, 0, 42, 45, 3, -123 },
			{ 0, -123, 45, 42, 43, 123, 3, -90, 654 }
		};
		Random rnd(4789);

		for (int i = 0; i < DE_LENGTH_OF_ARRAY(expected); i++)
		{
			rnd.shuffle(DE_ARRAY_BEGIN(items), DE_ARRAY_END(items));
			for(int j = 0; j < DE_LENGTH_OF_ARRAY(items); j++)
				DE_TEST_ASSERT(expected[i][j] == items[j]);
		}
	}
}

} // de