Ichthyostega
806db414dd
* Lumiera source code always was copyrighted by individual contributors * there is no entity "Lumiera.org" which holds any copyrights * Lumiera source code is provided under the GPL Version 2+ == Explanations == Lumiera as a whole is distributed under Copyleft, GNU General Public License Version 2 or above. For this to become legally effective, the ''File COPYING in the root directory is sufficient.'' The licensing header in each file is not strictly necessary, yet considered good practice; attaching a licence notice increases the likeliness that this information is retained in case someone extracts individual code files. However, it is not by the presence of some text, that legally binding licensing terms become effective; rather the fact matters that a given piece of code was provably copyrighted and published under a license. Even reformatting the code, renaming some variables or deleting parts of the code will not alter this legal situation, but rather creates a derivative work, which is likewise covered by the GPL! The most relevant information in the file header is the notice regarding the time of the first individual copyright claim. By virtue of this initial copyright, the first author is entitled to choose the terms of licensing. All further modifications are permitted and covered by the License. The specific wording or format of the copyright header is not legally relevant, as long as the intention to publish under the GPL remains clear. The extended wording was based on a recommendation by the FSF. It can be shortened, because the full terms of the license are provided alongside the distribution, in the file COPYING.
141 lines
4.2 KiB
C++
141 lines
4.2 KiB
C++
/*
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Random(Test) - verify framework for controlled random number generation
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Copyright (C)
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2024, Hermann Vosseler <Ichthyostega@web.de>
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**Lumiera** is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version. See the file COPYING for further details.
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* *****************************************************************/
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/** @file random-test.cpp
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** unit test \ref Random_test
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*/
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#include "lib/test/run.hpp"
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#include "lib/random.hpp"
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#include "lib/util.hpp"
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#include "lib/test/diagnostic-output.hpp"
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using util::isLimited;
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namespace lib {
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namespace test {
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/******************************************************************//**
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* @test demonstrate simple access to random number generation,
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* as well as the setup of controlled random number sequences.
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* @see random.hpp
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*/
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class Random_test : public Test
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{
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virtual void
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run (Arg)
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{
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simpleUsage();
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verify_distributionVariants();
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verify_reproducibleSequence();
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}
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/** @test demonstrate usage of default random number generators.
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* @note should [draw a seed](\ref Test::seedRand()) once per Test instance
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*/
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void
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simpleUsage()
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{
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seedRand();
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int r1 = rani();
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CHECK (0 <= r1 and r1 < RAND_MAX);
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int r2 = rani();
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CHECK (0 <= r2 and r2 < RAND_MAX);
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CHECK (r1 != r2); // may fail with very low probability
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}
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/** @test properties of predefined distributions provided for convenience
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* - the upper bound for `rani(bound)` is exclusive
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* - uniform distributions are sufficiently uniform
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* - spread of normal distribution is within expected scale
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*/
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void
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verify_distributionVariants()
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{
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double avg{0.0};
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const uint N = 1e6;
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for (uint i=0; i < N; ++i)
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avg += 1.0/N * rani (1000);
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auto expect = 500;
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auto error = fabs(avg/expect - 1);
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CHECK (error < 0.005);
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for (uint i=0; i < N; ++i)
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CHECK (isLimited(0, rani(5), 4));
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for (uint i=0; i < N; ++i)
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CHECK (0 != ranHash());
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auto sqr = [](double v){ return v*v; };
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double spread{0.0};
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for (uint i=0; i < N; ++i)
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spread += sqr (ranNormal() - 0.5);
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spread = sqrt (spread/N);
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CHECK (spread < 1.12);
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}
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/** @test demonstrate that random number sequences can be reproduced
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* - use a rigged SeedNucleus, always returning a fixed sees
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* - build two distinct random sequence generators, yet seeded
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* from the same source; they will produce the same sequence
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* - sequences can be re-shuffled by a seed value, so that
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* the following random numbers will start to differ
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* - but even this re-shuffling is deterministic
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*/
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void
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verify_reproducibleSequence()
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{
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class : public SeedNucleus
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{
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uint64_t getSeed() override { return 55; }
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}
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coreOfEvil;
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Random src1{coreOfEvil};
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int r1 = src1.i32();
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uint64_t r2 = src1.u64();
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double r3 = src1.uni();
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Random src2{coreOfEvil};
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CHECK (r1 == src2.i32());
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CHECK (r2 == src2.u64());
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CHECK (r3 == src2.uni());
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src1.reseed (coreOfEvil);
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CHECK (src1.u64() != src2.u64());
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src2.reseed (coreOfEvil);
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CHECK (src1.u64() != src2.u64());
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(void) src2.u64();
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CHECK (src1.u64() == src2.u64());
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CHECK (src1.i32() == src2.i32());
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CHECK (src1.uni() == src2.uni());
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}
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};
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LAUNCHER (Random_test, "unit common");
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}} // namespace lib::test
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