Merge pull request #323 from cicirello/refactor

Refactored KendallTauDistance, WeightedKendallTauDistance, CyclicEdgeDistance, CyclicRTypeDistance
cicirello · Mar 5, 2023 · dba2610 · dba2610
2 parents 3c12922 + 4b7d664
commit dba2610
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -4,12 +4,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased] - 2023-03-03
+## [Unreleased] - 2023-03-05
 
 ### Added
 
 ### Changed
-* Minor code improvements within Permutation and PermutationIterator classes.
+* Minor code improvements to Permutation and PermutationIterator classes.
+* Minor code improvements to KendallTauDistance and WeightedKendallTauDistance.
+* Minor code improvements to CyclicEdgeDistance and CyclicRTypeDistance.
 
 ### Deprecated
 

diff --git a/src/main/java/module-info.java b/src/main/java/module-info.java
@@ -29,7 +29,8 @@
  *
  * <p><a href="https://doi.org/10.21105/joss.00950"><img
  * src="http://joss.theoj.org/papers/10.21105/joss.00950/status.svg" alt="DOI:10.21105/joss.00950"
- * height="20" width="168"></a> <a href="https://central.sonatype.com/search?namespace=org.cicirello&q=jpt"><img
+ * height="20" width="168"></a> <a
+ * href="https://central.sonatype.com/search?namespace=org.cicirello&q=jpt"><img
  * src="https://img.shields.io/maven-central/v/org.cicirello/jpt.svg?logo=apachemaven" alt="Maven
  * Central" height="20" width="153"></a> <a
  * href="https://github.com/cicirello/JavaPermutationTools/releases"><img

diff --git a/src/main/java/org/cicirello/permutations/distance/CyclicEdgeDistance.java b/src/main/java/org/cicirello/permutations/distance/CyclicEdgeDistance.java
@@ -1,6 +1,6 @@
 /*
  * JavaPermutationTools - A Java library for computation on permutations.
- * Copyright 2005-2022 Vincent A. Cicirello, <https://www.cicirello.org/>.
+ * Copyright 2005-2023 Vincent A. Cicirello, <https://www.cicirello.org/>.
  *
  * JavaPermutationTools is free software: you can
  * redistribute it and/or modify it under the terms of the GNU
@@ -61,12 +61,14 @@ public int distance(Permutation p1, Permutation p2) {
     int countNonSharedEdges = 0;
     int[] successors2 = new int[p2.length()];
     for (int i = 0; i < successors2.length; i++) {
-      successors2[p2.get(i)] = p2.get((i + 1) % successors2.length);
+      successors2[p2.get(i)] = p2.get(indexCyclicAdjustment(i + 1, successors2.length));
     }
 
     for (int i = 0; i < successors2.length; i++) {
-      if (p1.get((i + 1) % successors2.length) != successors2[p1.get(i)]
-          && p1.get(i) != successors2[p1.get((i + 1) % successors2.length)]) countNonSharedEdges++;
+      int j = indexCyclicAdjustment(i + 1, successors2.length);
+      if (p1.get(j) != successors2[p1.get(i)] && p1.get(i) != successors2[p1.get(j)]) {
+        countNonSharedEdges++;
+      }
     }
 
     return countNonSharedEdges;
@@ -78,4 +80,8 @@ public int max(int length) {
     if (length == 4) return 2;
     return length;
   }
+
+  private int indexCyclicAdjustment(int i, int length) {
+    return i < length ? i : 0;
+  }
 }
diff --git a/src/main/java/org/cicirello/permutations/distance/CyclicRTypeDistance.java b/src/main/java/org/cicirello/permutations/distance/CyclicRTypeDistance.java
@@ -1,6 +1,6 @@
 /*
  * JavaPermutationTools - A Java library for computation on permutations.
- * Copyright 2005-2022 Vincent A. Cicirello, <https://www.cicirello.org/>.
+ * Copyright 2005-2023 Vincent A. Cicirello, <https://www.cicirello.org/>.
  *
  * JavaPermutationTools is free software: you can
  * redistribute it and/or modify it under the terms of the GNU
@@ -61,11 +61,13 @@ public int distance(Permutation p1, Permutation p2) {
     int countNonSharedEdges = 0;
     int[] successors2 = new int[p2.length()];
     for (int i = 0; i < successors2.length; i++) {
-      successors2[p2.get(i)] = p2.get((i + 1) % successors2.length);
+      successors2[p2.get(i)] = p2.get(indexCyclicAdjustment(i + 1, successors2.length));
     }
 
     for (int i = 0; i < successors2.length; i++) {
-      if (p1.get((i + 1) % successors2.length) != successors2[p1.get(i)]) countNonSharedEdges++;
+      if (p1.get(indexCyclicAdjustment(i + 1, successors2.length)) != successors2[p1.get(i)]) {
+        countNonSharedEdges++;
+      }
     }
     return countNonSharedEdges;
   }
@@ -75,4 +77,8 @@ public int max(int length) {
     if (length <= 2) return 0;
     return length;
   }
+
+  private int indexCyclicAdjustment(int i, int length) {
+    return i < length ? i : 0;
+  }
 }
diff --git a/src/main/java/org/cicirello/permutations/distance/EditDistance.java b/src/main/java/org/cicirello/permutations/distance/EditDistance.java
@@ -1,6 +1,6 @@
 /*
  * JavaPermutationTools - A Java library for computation on permutations.
- * Copyright 2005-2022 Vincent A. Cicirello, <https://www.cicirello.org/>.
+ * Copyright 2005-2023 Vincent A. Cicirello, <https://www.cicirello.org/>.
  *
  * JavaPermutationTools is free software: you can
  * redistribute it and/or modify it under the terms of the GNU
@@ -131,7 +131,7 @@ public double distancef(Permutation p1, Permutation p2) {
   if (combined <= changeCost) {
   	return (length-1)*combined;
   }
-  if (length % 2 == 0) {
+  if ((length & 1) == 0) {
   	double m1 = (length-1)*combined;
   	double m2 = length*changeCost;
   	double m3 = combined + (length-2)*changeCost;

diff --git a/src/main/java/org/cicirello/permutations/distance/KendallTauDistance.java b/src/main/java/org/cicirello/permutations/distance/KendallTauDistance.java
@@ -1,6 +1,6 @@
 /*
  * JavaPermutationTools - A Java library for computation on permutations.
- * Copyright 2005-2022 Vincent A. Cicirello, <https://www.cicirello.org/>.
+ * Copyright 2005-2023 Vincent A. Cicirello, <https://www.cicirello.org/>.
  *
  * JavaPermutationTools is free software: you can
  * redistribute it and/or modify it under the terms of the GNU
@@ -112,16 +112,8 @@ private int merge(int[] array, int first, int midPlus, int lastPlus) {
         k++;
       }
     }
-    while (i < left.length) {
-      array[k] = left[i];
-      i++;
-      k++;
-    }
-    while (j < right.length) {
-      array[k] = right[j];
-      j++;
-      k++;
-    }
+    System.arraycopy(left, i, array, k, left.length - i);
+    System.arraycopy(right, j, array, k, right.length - j);
     return count;
   }
 }
diff --git a/src/main/java/org/cicirello/permutations/distance/WeightedKendallTauDistance.java b/src/main/java/org/cicirello/permutations/distance/WeightedKendallTauDistance.java
@@ -1,6 +1,6 @@
 /*
  * JavaPermutationTools: A Java library for computation on permutations and sequences.
- * Copyright (C) 2018-2022 Vincent A. Cicirello, <https://www.cicirello.org/>.
+ * Copyright (C) 2018-2023 Vincent A. Cicirello, <https://www.cicirello.org/>.
  *
  * This file is part of JavaPermutationTools (https://jpt.cicirello.org/).
  *
@@ -149,16 +149,8 @@ private double merge(int[] array, double[] w, int first, int midPlus, int lastPl
         k++;
       }
     }
-    while (i < left.length) {
-      array[k] = left[i];
-      i++;
-      k++;
-    }
-    while (j < right.length) {
-      array[k] = right[j];
-      j++;
-      k++;
-    }
+    System.arraycopy(left, i, array, k, left.length - i);
+    System.arraycopy(right, j, array, k, right.length - j);
     return weightedCount;
   }
 }