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#include "HCheckConfig.h"
#include "catch.hpp"
#include "util/HighsIntegers.h"
const bool dev_run = false;
TEST_CASE("HighsIntegers", "[util]") {
double x1 = 6.4700675;
double x2 = 0.27425;
double x3 = 5.68625;
// simple test case, that requires denominators above 1000, but not
// well behaved ones as they contain multiple powers of two
// this should get found by multiplying them by 600 before running
// the continued fraction algorithm
std::vector<double> tmp{x1, x2, x3};
double integralscalar = HighsIntegers::integralScale(tmp, 1e-6, 1e-9);
REQUIRE(integralscalar == 400000);
if (dev_run) printf("integral scalar is %g\n", integralscalar);
// stress test the algorithm with a constructed case:
// add 6 fractions with prime number denominators just below 1000.
// This will blow up the common denominator to a value around 9e17
// with this magnitude the results are still representable
// in an 64bit integers, but not in 53bits double precision.
// The double precision error is already far above 1.0
// so for computing the correct fraction it is necessary to use HighsCDouble
// which represents a roughly quad precision number as the unevaluated sum of
// two double precision numbers, otherwise the algorithm will fail.
int64_t primes[] = {967, 971, 977, 983};
std::vector<double> values{1.0 / primes[0], 2.0 / primes[1], 3.0 / primes[2],
4.0 / primes[3]};
integralscalar = HighsIntegers::integralScale(values, 1e-6, 1e-6);
REQUIRE(integralscalar == primes[0] * primes[1] * primes[2] * primes[3]);
if (dev_run) printf("integral scalar is %g\n", integralscalar);
}
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