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commit b19aed99d88aa7cc6bcd5f7c63063bdbae66f65e
Author: Alex Herbert <aherb...@apache.org>
AuthorDate: Tue Jul 9 15:31:40 2024 +0100
Update transformed sampler test to allow better failure identification
Change tolerance from 1 ulp to 2 ulp.
Addresses test failures observed during release of version 1.6.
---
.../sampling/distribution/StableSamplerTest.java | 73 ++++++++++------------
1 file changed, 33 insertions(+), 40 deletions(-)
diff --git
a/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/distribution/StableSamplerTest.java
b/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/distribution/StableSamplerTest.java
index cf32008b..86cd9d97 100644
---
a/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/distribution/StableSamplerTest.java
+++
b/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/distribution/StableSamplerTest.java
@@ -17,6 +17,7 @@
package org.apache.commons.rng.sampling.distribution;
import java.util.function.Supplier;
+import java.util.stream.Stream;
import org.apache.commons.rng.UniformRandomProvider;
import org.apache.commons.rng.core.source64.SplitMix64;
import org.apache.commons.rng.sampling.RandomAssert;
@@ -28,6 +29,9 @@ import
org.apache.commons.rng.sampling.distribution.StableSampler.WeronStableSam
import org.apache.commons.rng.simple.RandomSource;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
/**
* Tests for the class {@link StableSampler}.
@@ -2044,44 +2048,30 @@ class StableSamplerTest {
RandomAssert.assertProduceSameSequence(sampler1, sampler2);
}
- /**
- * Test the implementation of the transformed sampler (scaled and
translated).
- */
- @Test
- void testTransformedSampler() {
- // Gaussian case
- // The Gaussian case has its own scaling where the StdDev is gamma *
sqrt(2).
- // (N(x) * sqrt(2)) * gamma != N(x) * (sqrt(2) * gamma)
- // Test with a delta
- testTransformedSampler(2.0, 0.0, 1);
- // Cauchy case
- testTransformedSampler(1.0, 0.0);
- // Levy case
- testTransformedSampler(0.5, 1.0);
- // Symmetric case
- testTransformedSampler(1.3, 0.0);
- // Alpha 1 case
- testTransformedSampler(1.0, 0.23);
- // Alpha close to 1
- testTransformedSampler(Math.nextUp(1.0), 0.23);
- // General case
- testTransformedSampler(1.3, 0.1);
- // Small alpha case
- testTransformedSampler(1e-5, 0.1);
- // Large alpha case.
- // This hits the case for computing tau from (1-alpha) -> -1.
- testTransformedSampler(1.99, 0.1);
- }
-
- /**
- * Test the implementation of the transformed sampler (scaled and
translated).
- * The transformed output must match exactly.
- *
- * @param alpha Alpha.
- * @param beta Beta.
- */
- private static void testTransformedSampler(double alpha, double beta) {
- testTransformedSampler(alpha, beta, 0);
+ static Stream<Arguments> testTransformedSampler() {
+ return Stream.of(
+ // Gaussian case
+ // The Gaussian case has its own scaling where the StdDev is gamma
* sqrt(2).
+ // (N(x) * sqrt(2)) * gamma != N(x) * (sqrt(2) * gamma)
+ // Test with a delta
+ Arguments.of(2.0, 0.0, 2),
+ // Cauchy case
+ Arguments.of(1.0, 0.0, 0),
+ // Levy case
+ Arguments.of(0.5, 1.0, 0),
+ // Symmetric case
+ Arguments.of(1.3, 0.0, 0),
+ // Alpha 1 case
+ Arguments.of(1.0, 0.23, 0),
+ // Alpha close to 1
+ Arguments.of(Math.nextUp(1.0), 0.23, 0),
+ // General case
+ Arguments.of(1.3, 0.1, 0),
+ // Small alpha case
+ Arguments.of(1e-5, 0.1, 0),
+ // Large alpha case.
+ // This hits the case for computing tau from (1-alpha) -> -1.
+ Arguments.of(1.99, 0.1, 0));
}
/**
@@ -2092,7 +2082,9 @@ class StableSamplerTest {
* @param beta Beta.
* @param ulp Allowed ULP difference.
*/
- private static void testTransformedSampler(double alpha, double beta, int
ulp) {
+ @ParameterizedTest
+ @MethodSource
+ void testTransformedSampler(double alpha, double beta, int ulp) {
final UniformRandomProvider[] rngs = RandomAssert.createRNG(2);
final UniformRandomProvider rng1 = rngs[0];
final UniformRandomProvider rng2 = rngs[1];
@@ -2106,7 +2098,8 @@ class StableSamplerTest {
for (int i = 0; i < 10; i++) {
final double x1 = sampler1.sample();
final double x2 = sampler2.sample();
- Assertions.assertEquals(x1, x2, ulp * Math.ulp(x1));
+ Assertions.assertEquals(x1, x2, ulp * Math.ulp(x1),
+ () -> String.format("alpha=%s, beta=%s, ulp=%d", alpha,
beta, ulp));
}
}
}
