[commons-math] 05/05: Use a LinkedHashMap to respect the order of the input data

[ah...@apache.org]

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

commit ab9b0b0c2d0913e7f2a894650255564a40b05277
Author: aherbert <ah...@apache.org>
AuthorDate: Fri Dec 2 15:08:03 2022 +0000

    Use a LinkedHashMap to respect the order of the input data
    
    Note: The int/real enumerated distributions do not specify that the
    input must be sorted. This change supports the legacy behaviour enforced
    by the unit test which is assuming input values are processed in
    encounter order (which happens to be sorted).
    
    Given int and double have a natural ordering it may be better to update
    the distribution to sort input values. However this would contradict the
    enumerated distribution which respects the input order of the list used
    in the constructor.
---
 .../math4/legacy/distribution/EnumeratedIntegerDistribution.java    | 6 +++---
 .../math4/legacy/distribution/EnumeratedRealDistribution.java       | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/EnumeratedIntegerDistribution.java b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/EnumeratedIntegerDistribution.java
index 010e82e86..0e0cf1b83 100644
--- a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/EnumeratedIntegerDistribution.java
+++ b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/EnumeratedIntegerDistribution.java
@@ -17,7 +17,7 @@
 package org.apache.commons.math4.legacy.distribution;
 
 import java.util.ArrayList;
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -68,7 +68,7 @@ public class EnumeratedIntegerDistribution extends AbstractIntegerDistribution {
                NotFiniteNumberException,
                NotANumberException {
         innerDistribution = new EnumeratedDistribution<>(createDistribution(singletons,
-                                                                                   probabilities));
+                                                                            probabilities));
     }
 
     /**
@@ -78,7 +78,7 @@ public class EnumeratedIntegerDistribution extends AbstractIntegerDistribution {
      * @param data input dataset
      */
     public EnumeratedIntegerDistribution(final int[] data) {
-        final Map<Integer, Integer> dataMap = new HashMap<>();
+        final Map<Integer, Integer> dataMap = new LinkedHashMap<>();
         for (int value : data) {
             dataMap.merge(value, 1, Integer::sum);
         }
diff --git a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/EnumeratedRealDistribution.java b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/EnumeratedRealDistribution.java
index 2d33dca8b..77385c8d4 100644
--- a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/EnumeratedRealDistribution.java
+++ b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/EnumeratedRealDistribution.java
@@ -17,7 +17,7 @@
 package org.apache.commons.math4.legacy.distribution;
 
 import java.util.ArrayList;
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -80,7 +80,7 @@ public class EnumeratedRealDistribution
      * @param data input dataset
      */
     public EnumeratedRealDistribution(final double[] data) {
-        final Map<Double, Integer> dataMap = new HashMap<>();
+        final Map<Double, Integer> dataMap = new LinkedHashMap<>();
         for (double value : data) {
             dataMap.merge(value, 1, Integer::sum);
         }