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Matthieu Schaller authored
Added unit test to verify that the random numbers are generated uniformly over [0,1] for all IDs and time-steps.
Matthieu Schaller authoredAdded unit test to verify that the random numbers are generated uniformly over [0,1] for all IDs and time-steps.
testRandom.c 2.65 KiB
/*******************************************************************************
* This file is part of SWIFT.
* Copyright (C) 2019 Matthieu Schaller (schaller@strw.leidenuniv.nl)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
******************************************************************************/
/* Config parameters. */
#include "../config.h"
#include <fenv.h>
/* Local headers. */
#include "swift.h"
int main(int argc, char* argv[]) {
/* Initialize CPU frequency, this also starts time. */
unsigned long long cpufreq = 0;
clocks_set_cpufreq(cpufreq);
/* Choke on FPEs */
#ifdef HAVE_FE_ENABLE_EXCEPT
feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
#endif
/* Get some randomness going */
const int seed = time(NULL);
message("Seed = %d", seed);
srand(seed);
/* Time-step size */
const int time_bin = 29;
/* Try a few different values for the ID */
for (int i = 0; i < 20; ++i) {
const long long id = rand() * (1LL << 31) + rand();
const integertime_t increment = (1LL << time_bin);
message("Testing id=%lld time_bin=%d", id, time_bin);
double total = 0., total2 = 0.;
int count = 0;
/* Check that the numbers are uniform over the full-range of useful
* time-steps */
for (integertime_t ti_current = 0LL; ti_current < max_nr_timesteps;
ti_current += increment) {
ti_current += increment;
const double r =
random_unit_interval(id, ti_current, random_number_star_formation);
total += r;
total2 += r * r;
count++;
}
const double mean = total / (double)count;
const double var = total2 / (double)count - mean * mean;
/* Verify that the mean and variance match the expected values for a uniform
* distribution */
if ((fabs(mean - 0.5) / 0.5 > 1e-4) ||
(fabs(var - 1. / 12.) / (1. / 12.) > 1e-4)) {
message("Test failed!");
message("Result: count=%d mean=%f var=%f", count, mean, var);
message("Expected: count=%d mean=%f var=%f", count, 0.5f, 1. / 12.);
return 1;
}
}
return 0;
}