[commons-statistics] 03/03: Remove checkedProbability method from the inverse

[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 a5892daac03a09ad44478499c3dc28ab6da27a21
Author: aherbert <ah...@apache.org>
AuthorDate: Fri Jan 21 16:59:10 2022 +0000

    Remove checkedProbability method from the inverse
    
    This method is only of use for bug reporting extremely an unlikely
    event. It will negatively impact performance for all distributions
    during computation of the inverse.
    
    The extreme bounds of discrete distributions are tested in unit tests.
    Any distributions where NaN values are potentially expected (e.g. zero
    divide by zero; infinity - infinity) should use units tests to check
    extreme parameterisations.
---
 .../distribution/AbstractDiscreteDistribution.java | 24 ++--------------------
 1 file changed, 2 insertions(+), 22 deletions(-)

diff --git a/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/AbstractDiscreteDistribution.java b/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/AbstractDiscreteDistribution.java
index e519bbc..81b426c 100644
--- a/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/AbstractDiscreteDistribution.java
+++ b/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/AbstractDiscreteDistribution.java
@@ -164,8 +164,8 @@ abstract class AbstractDiscreteDistribution
         // cdf(x) >= p
         // sf(x)  <= q
         final IntUnaryOperator fun = complement ?
-            x -> Double.compare(q, checkedProbability(survivalProbability(x))) :
-            x -> Double.compare(checkedProbability(cumulativeProbability(x)), p);
+            x -> Double.compare(q, survivalProbability(x)) :
+            x -> Double.compare(cumulativeProbability(x), p);
 
         if (lower == Integer.MIN_VALUE) {
             if (fun.applyAsInt(lower) >= 0) {
@@ -238,26 +238,6 @@ abstract class AbstractDiscreteDistribution
         return (int) upper;
     }
 
-    /**
-     * Checks the probability function result for {@code NaN}.
-     * Throws {@code IllegalStateException} if the cumulative
-     * probability function returns {@code NaN}.
-     *
-     * <p>TODO: Q. Is this required? The bisection search will
-     * eventually return if NaN is computed. Check the origin
-     * of this in Commons Math. Its origins may be for debugging.
-     *
-     * @param result Probability
-     * @return the probability.
-     * @throws IllegalStateException if the probability is {@code NaN}.
-     */
-    private static double checkedProbability(double result) {
-        if (Double.isNaN(result)) {
-            throw new IllegalStateException("Internal error");
-        }
-        return result;
-    }
-
     /** {@inheritDoc} */
     @Override
     public DiscreteDistribution.Sampler createSampler(final UniformRandomProvider rng) {