libcruft-util/test/rand.cpp

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2013-08-05 21:43:16 +10:00
#include "../random.hpp"
#include "../debug.hpp"
#include <iostream>
#include <cmath>
#include <cstdlib>
#include <ctime>
using namespace std;
// TODO: Use a more robust test like Chi-Square
void
test_bool (void) {
static const unsigned ITERATIONS = 8192;
static const unsigned THRESHOLD = ITERATIONS / 10;
unsigned counts[2] = { 0, 0 };
for (unsigned i = 0; i < ITERATIONS; ++i)
++counts[util::random<bool> () ? 0 : 1];
unsigned diff = counts[0] > counts[1] ?
counts[0] - counts[1] :
counts[1] - counts[0];
CHECK_LT (diff, THRESHOLD);
}
// TODO: Use a more robust test like Kolmogorov-Smirnov
void
test_float (void) {
static const unsigned BUCKETS = 8;
static const unsigned ITERATIONS = 8912;
static const unsigned EXPECTED = ITERATIONS / BUCKETS;
static const float THRESHOLD = EXPECTED / 10;
unsigned counts[BUCKETS] = { 0 };
for (unsigned i = 0; i < ITERATIONS; ++i)
++counts[unsigned (util::random<float> () * BUCKETS)];
for (unsigned c: counts) {
unsigned diff = EXPECTED > c ?
EXPECTED - c :
c - EXPECTED;
CHECK_LT (diff, THRESHOLD);
}
}
int
main (int, char **) {
srand (time (NULL));
test_bool ();
test_float ();
return EXIT_SUCCESS;
}