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xo-ratio: + unit test

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Roland Conybeare 2024-04-18 17:07:01 -04:00
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utest/ratio.test.cpp Normal file
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/** @file ratio.utest.cpp **/
#include "xo/ratio/ratio.hpp"
#include "xo/ratio/ratio_iostream.hpp"
#include "xo/randomgen/random_seed.hpp"
#include "xo/randomgen/xoshiro256.hpp"
#include "xo/indentlog/scope.hpp"
#include "xo/indentlog/print/vector.hpp"
#include "xo/indentlog/print/array.hpp"
#include "xo/indentlog/print/tag.hpp"
//#include "xo/indentlog/print/hex.hpp"
#include <catch2/catch.hpp>
#include <random>
#include <numeric>
namespace xo {
using std::exponential_distribution;
using std::bernoulli_distribution;
namespace ut {
template <typename Int>
struct ratio_distribution {
ratio_distribution(double sign_prob, double int_lambda)
: sign_dist_{sign_prob}, int_dist_{int_lambda} {}
template <typename Rng>
xo::ratio::ratio<Int>
random_ratio(Rng & rng) {
Int num_sign = sign_dist_(rng) ? -1 : +1;
Int num = num_sign * (1 + int_dist_(rng));
Int den_sign = sign_dist_(rng) ? -1 : +1;
Int den = den_sign * (1 + int_dist_(rng));
return xo::ratio::ratio(num, den).reduce();
}
template <typename Rng>
xo::ratio::ratio<Int> operator()(Rng & rng) {
return random_ratio(rng);
}
/* generate negative numbers some of the time */
bernoulli_distribution sign_dist_;
/* create ratios involving integers, but don't need integers to be too large */
exponential_distribution<double> int_dist_;
};
template <typename Rng>
void
ratio_tests(Rng & rng)
{
constexpr bool debug_flag = true;
std::size_t n_ratio = 25;
std::size_t n_experiment = n_ratio * n_ratio / 4;
/* want to avoid integer overflow when exponentiating */
constexpr int max_pwr = 5;
scope log(XO_DEBUG2(debug_flag, "ratio_tests"));
log && log(xtag("n_ratio", n_ratio));
ratio_distribution<int> ratio_dist(0.25 /*sign_prob*/,
0.05 /*lambda */);
bernoulli_distribution sign_dist(0.5);
exponential_distribution<double> power_dist(0.2 /*lambda*/);
std::vector<xo::ratio::ratio<int>> ratio_v;
/* ensure 0, 1, -1 all present */
ratio_v.push_back(xo::ratio::ratio<int>(0,1));
ratio_v.push_back(xo::ratio::ratio<int>(1,1));
ratio_v.push_back(xo::ratio::ratio<int>(-1,1));
for (std::uint32_t i=0, n=n_ratio - ratio_v.size(); i<n; ++i) {
ratio_v.push_back(ratio_dist(rng));
REQUIRE(std::gcd(ratio_v[i].num(), ratio_v[i].den()) == 1);
}
INFO(XTAG(ratio_v));
for (std::uint32_t i=0; i<n_experiment; ++i) {
INFO(tostr(XTAG(i), XTAG(n_experiment)));
/* choose a couple of ratios at random */
auto ratio1 = ratio_v[rng() % n_ratio];
auto ratio2 = ratio_v[rng() % n_ratio];
double ratio1_approx = ratio1.num() / static_cast<double>(ratio1.den());
double ratio2_approx = ratio2.num() / static_cast<double>(ratio2.den());
{
auto sum = ratio1 + ratio2;
double sum_approx = sum.num() / static_cast<double>(sum.den());
log && log(XTAG(ratio1), XTAG(ratio2), XTAG(sum));
REQUIRE(sum_approx == Approx(ratio1_approx + ratio2_approx).epsilon(1e-6));
REQUIRE(std::gcd(sum.num(), sum.den()) == 1);
REQUIRE(sum.den() > 0);
/* comparison tests. piggyback on sum */
{
auto cmp_approx = (sum_approx <=> ratio1_approx);
REQUIRE(cmp_approx == (sum <=> ratio1));
}
{
bool eq = (sum == ratio1);
bool eq_approx = (sum_approx == ratio1_approx);
REQUIRE(eq == eq_approx);
}
{
bool ne = (sum != ratio1);
bool ne_approx = (sum_approx != ratio1_approx);
REQUIRE(ne == ne_approx);
}
{
bool gt = (sum > ratio1);
bool gt_approx = (sum_approx > ratio1_approx);
REQUIRE(gt == gt_approx);
}
{
bool ge = (sum >= ratio1);
bool ge_approx = (sum_approx >= ratio1_approx);
REQUIRE(ge == ge_approx);
}
{
bool lt = (sum > ratio1);
bool lt_approx = (sum_approx > ratio1_approx);
REQUIRE(lt == lt_approx);
}
{
bool le = (sum >= ratio1);
bool le_approx = (sum_approx >= ratio1_approx);
REQUIRE(le == le_approx);
}
}
{
auto neg = -ratio1;
double neg_approx = neg.num() / static_cast<double>(neg.den());
log && log(XTAG(ratio1), XTAG(neg));
REQUIRE(neg_approx == Approx(-ratio1_approx).epsilon(1e-06));
REQUIRE(std::gcd(neg.num(), neg.den()) == 1);
REQUIRE(neg.den() > 0);
}
{
auto diff = ratio1 - ratio2;
double diff_approx = diff.num() / static_cast<double>(diff.den());
log && log(XTAG(ratio1), XTAG(ratio2), XTAG(diff));
REQUIRE(diff_approx == Approx(ratio1_approx - ratio2_approx).epsilon(1e-6));
REQUIRE(std::gcd(diff.num(), diff.den()) == 1);
REQUIRE(diff.den() > 0);
}
{
auto prod = ratio1 * ratio2;
double prod_approx = prod.num() / static_cast<double>(prod.den());
log && log(XTAG(ratio1), XTAG(ratio2), XTAG(prod));
REQUIRE(prod_approx == Approx(ratio1_approx * ratio2_approx).epsilon(1e-6));
REQUIRE(std::gcd(prod.num(), prod.den()) == 1);
REQUIRE(prod.den() > 0);
}
{
auto div = ratio1 * ratio2;
double div_approx = div.num() / static_cast<double>(div.den());
log && log(XTAG(ratio1), XTAG(ratio2), XTAG(div));
REQUIRE(div_approx == Approx(ratio1_approx * ratio2_approx).epsilon(1e-6));
REQUIRE(std::gcd(div.num(), div.den()) == 1);
REQUIRE(div.den() > 0);
}
{
int exp = (sign_dist(rng) ? -1 : +1) * power_dist(rng);
if (std::abs(exp) >= max_pwr) {
exp = (std::signbit(exp) ? -1 : +1) * max_pwr;
}
auto pwr = ratio1.power(exp);
double pwr_approx = pwr.num() / static_cast<double>(pwr.den());
log && log(XTAG(ratio1), XTAG(exp), XTAG(pwr));
REQUIRE(pwr_approx == Approx(::pow(ratio1_approx, exp)).epsilon(1e-6));
REQUIRE(std::gcd(pwr.num(), pwr.den()) == 1);
REQUIRE(pwr.den() >= 0);
}
{
auto ratio1_str = ratio1.template to_str<20>();
log && log(XTAG(ratio1_str));
}
}
}
TEST_CASE("ratio", "[ratio]") {
//constexpr bool c_debug_flag = false;
// can get bits from /dev/random by uncommenting the 2nd line below
uint64_t seed = 5521646833469436535ul;
//rng::Seed<rng::xoshiro256ss> seed;
//std::cerr << "ratio: seed=" << seed << std::endl;
auto rng = rng::xoshiro256ss(seed);
ratio_tests(rng);
} /*TEST_CASE(ratio)*/
} /*namespace ut*/
} /*namespace xo*/
/** end ratio.utest.cpp **/