[commons-statistics] 04/12: Correct relative error assertion

[ah...@apache.org]

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aherbert pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-statistics.git

commit 89d3af820ae420dd50faf00a0d39e0f19c991197
Author: Alex Herbert <ah...@apache.org>
AuthorDate: Mon Nov 21 18:33:23 2022 +0000

    Correct relative error assertion
    
    Test has been updated to use exact equality. The previous delta value
    was incorrect as it was effectively: |a-b| <= (a - b) * 1e-16. This only
    works for equal values.
---
 .../statistics/distribution/LogisticDistributionTest.java   | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/commons-statistics-distribution/src/test/java/org/apache/commons/statistics/distribution/LogisticDistributionTest.java b/commons-statistics-distribution/src/test/java/org/apache/commons/statistics/distribution/LogisticDistributionTest.java
index 5475603..985bde3 100644
--- a/commons-statistics-distribution/src/test/java/org/apache/commons/statistics/distribution/LogisticDistributionTest.java
+++ b/commons-statistics-distribution/src/test/java/org/apache/commons/statistics/distribution/LogisticDistributionTest.java
@@ -63,16 +63,17 @@ class LogisticDistributionTest extends BaseContinuousDistributionTest {
         Assertions.assertEquals(Double.POSITIVE_INFINITY, Math.exp(-x0));
         Assertions.assertEquals(Double.NaN, Math.exp(-x0) / Math.pow(1 + Math.exp(-x0), 2.0));
 
-        // Computed using scipy.stats logistic
+        // Computed using scipy.stats logistic.
+        // These values of exp(x) will create overflow.
         final double[] x = {710, 720, 730, 740, 750};
         final double[] values = {4.47628622567513e-309,
             2.03223080241836e-313, 9.22631526816382e-318,
             4.19955798965060e-322, 0.00000000000000e+000};
-        for (int i = 0; i < x.length; i++) {
-            final double d = dist.density(x[i]);
-            Assertions.assertEquals(values[i], d, (values[i] - d) * 1e-16);
-            // Test symmetry. These values of x will create overflow.
-            Assertions.assertEquals(d, dist.density(-x[i]));
+        testDensity(dist, x, values, DoubleTolerances.equals());
+
+        // Test symmetry.
+        for (final double xi : x) {
+            Assertions.assertEquals(dist.density(xi), dist.density(-xi), () -> Double.toString(xi));
         }
     }