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new 1e8ce0d9 Document potential performance limitations and viable
alternatives
1e8ce0d9 is described below
commit 1e8ce0d9d769974d2c9af19209e69c8f44c1a35c
Author: Alex Herbert <[email protected]>
AuthorDate: Thu Aug 27 15:15:01 2026 +0100
Document potential performance limitations and viable alternatives
---
.../statistics/inference/UnconditionedExactTest.java | 10 ++++++++++
src/changes/changes.xml | 16 +++++++++++-----
2 files changed, 21 insertions(+), 5 deletions(-)
diff --git
a/commons-statistics-inference/src/main/java/org/apache/commons/statistics/inference/UnconditionedExactTest.java
b/commons-statistics-inference/src/main/java/org/apache/commons/statistics/inference/UnconditionedExactTest.java
index 2f5abaad..1e4cbb96 100644
---
a/commons-statistics-inference/src/main/java/org/apache/commons/statistics/inference/UnconditionedExactTest.java
+++
b/commons-statistics-inference/src/main/java/org/apache/commons/statistics/inference/UnconditionedExactTest.java
@@ -70,6 +70,16 @@ import
org.apache.commons.statistics.inference.BrentOptimizer.PointValuePair;
* number of points}. The best candidates are optionally used as the start
point for an
* {@linkplain #withOptimize(boolean) optimized} search for a local maxima.
*
+ * <p><strong>Maximum number of tables</strong>
+ *
+ * <p>The maximum number of tables is equal to (m + 1) * (n + 1). The p-value
computation
+ * must track all tables as or more extreme than the observed table. This is
done using an
+ * expandable {@code int[]} array, and computation is limited to the maximum
capacity of
+ * an array. When the input counts are large this can result in excessive
computation and
+ * memory consumption. If performance is a limiting factor, users are advised
to check the
+ * table if the counts are potentially large, or from untrusted input, and
consider
+ * switching to an alternative such as the {@link ChiSquareTest} or {@link
GTest}.
+ *
* <p>References:
* <ol>
* <li>
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 58768a9d..94d4e1bb 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -53,27 +53,33 @@ If the output is not quite correct, check for invisible
trailing spaces!
</properties>
<body>
<release version="1.4" date="TBD" description="Adds new features (requires
Java 8).">
- <action dev="aherbert" type="fix" due-to="Security scan, Aex Herbert"
issue="STATISTICS-98">
+ <action dev="aherbert" type="update" due-to="Security scan, Alex
Herbert">
+ "UnconditionedExactTest": Update documentation on possible long
runtime and
+ high memory consumption for large table counts. For performance
sensitive
+ code with large 2x2 contigency counts users can switch to an
alternative such
+ as a chi-square or G test.
+ </action>
+ <action dev="aherbert" type="fix" due-to="Security scan, Alex Herbert"
issue="STATISTICS-98">
"SignificanceResult": Raise an exception if the p-value is invalid when
comparing the p-value to a significance level. Corrects silent
rejection
of the null hypothesis if the computed p-value is NaN.
</action>
- <action dev="aherbert" type="fix" due-to="Security scan, Aex Herbert"
issue="STATISTICS-97">
+ <action dev="aherbert" type="fix" due-to="Security scan, Alex Herbert"
issue="STATISTICS-97">
"TTest/OneWayAnova": Checks added for arguments that invalidate the
test
statistic: non-finite values in input arrays; and NaN mean arguments.
</action>
- <action dev="aherbert" type="update" due-to="Security scan, Aex Herbert">
+ <action dev="aherbert" type="update" due-to="Security scan, Alex
Herbert">
"FisherExactTest/HypergeometricDistribution": Update documentation
on possible long runtime when the hypergeometric distribution
cumulative probability functions are evaluated with parameters that
create a very large support width. Users are advised to guard the
arguments to the FisherExactTest and HypergeometricDistribution.
</action>
- <action dev="aherbert" type="fix" due-to="Security scan, Aex Herbert"
issue="STATISTICS-96">
+ <action dev="aherbert" type="fix" due-to="Security scan, Alex Herbert"
issue="STATISTICS-96">
"commons-statistics-distribution": Checks added to distribution factory
functions for NaN parameters that invalidate the distribution.
</action>
- <action dev="aherbert" type="fix" due-to="Security scan, Aex Herbert"
issue="STATISTICS-95">
+ <action dev="aherbert" type="fix" due-to="Security scan, Alex Herbert"
issue="STATISTICS-95">
"NormalConfidenceInterval": Validate mean is finite and variance is
positive finite.
</action>
</release>
