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update tests to be more robust

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This commit is contained in:
Patrick A Myers 2023-01-13 16:51:13 -05:00
parent 4122c02ad4
commit d0e071be94
1 changed files with 38 additions and 23 deletions
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61
tests/cpp_unit_tests/test_distribution.cpp
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@ -1,14 +1,14 @@
#include "openmc/distribution.h"
#include "openmc/random_lcg.h"
#include <catch2/catch_test_macros.hpp>
#include <catch2/catch_approx.hpp>
#include <pugixml.hpp>
TEST_CASE("Test alias method sampling of a discrete distribution")
{
int n_samples = 1e6;
constexpr int n_samples = 1000000;
double x[5] = {-1.6, 1.1, 20.3, 4.7, 0.9};
double p[5] = {0.2, 0.1, 0.5, 0.05, 0.15};
double samples[n_samples];
double p[5] = {0.2, 0.1, 0.65, 0.02, 0.03};
// Initialize distribution
openmc::Discrete dist(x, p, 5);
@ -20,24 +20,31 @@ TEST_CASE("Test alias method sampling of a discrete distribution")
mean += x[i] * p[i];
}
// Sample distribution and calculate mean
// Sample distribution and calculate mean, standard deviation, and number of
// x[0] sampled
double dist_mean = 0.0;
for (size_t i = 0; i < n_samples; i++) {
samples[i] = dist.sample(&seed);
dist_mean += samples[i];
}
dist_mean /= n_samples;
// Calculate standard deviation
double std = 0.0;
for (size_t i = 0; i < n_samples; i++) {
std += (samples[i] - dist_mean) * (samples[i] - dist_mean);
}
std /= n_samples;
int counter = 0;
// Require sampled distribution mean is within 3 standard deviations of the
for (size_t i = 0; i < n_samples; i++) {
auto sample = dist.sample(&seed);
std += sample * sample / n_samples;
dist_mean += sample;
if (sample == x[0])
counter++;
}
dist_mean /= n_samples;
std -= dist_mean * dist_mean;
// Require sampled distribution mean is within 4 standard deviations of the
// expected mean
REQUIRE(std::abs(dist_mean - mean) < 4 * std);
// Require counter of number of x[0] is within 4 standard deviations of
// 200,000
REQUIRE(std::abs(counter - n_samples * p[0]) < 4 * std);
}
TEST_CASE("Test alias sampling method for pugixml constructor")
@ -47,17 +54,25 @@ TEST_CASE("Test alias sampling method for pugixml constructor")
pugi::xml_node energy = doc.append_child("energy");
pugi::xml_node parameters = energy.append_child("parameters");
parameters.append_child(pugi::node_pcdata)
.set_value("17140457.745328166 1.0");
.set_value("800 500000 30000 0.1 0.6 0.3");
// Initialize discrete distribution and seed
openmc::Discrete dist(energy);
uint64_t seed = openmc::init_seed(0, 0);
auto sample = dist.sample(&seed);
// Assertions
REQUIRE(dist.x().size() == 1);
REQUIRE(dist.p().size() == 1);
REQUIRE(dist.alias().size() == 0);
REQUIRE(dist.x()[0] == 17140457.745328166);
REQUIRE(dist.p()[0] == 1.0);
REQUIRE(dist.sample(&seed) == 17140457.745328166);
REQUIRE(dist.x().size() == 3);
REQUIRE(dist.prob().size() == 3);
REQUIRE(dist.alias().size() == 3);
openmc::vector<double> correct_x = {800, 500000, 30000};
openmc::vector<double> correct_prob = {0.3, 1.0, 0.9};
openmc::vector<size_t> correct_alias = {1, 0, 1};
for (size_t i = 0; i < 3; i++) {
REQUIRE(dist.x()[i] == correct_x[i]);
REQUIRE(dist.prob()[i] == Catch::Approx(correct_prob[i]).epsilon(1e-12));
REQUIRE(dist.alias()[i] == correct_alias[i]);
}
}