remove constraint of self-referencing edges

iTitus · Jan 24, 2022 · 5101d06 · 5101d06
1 parent 15d7795
commit 5101d06
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Showing 3 changed files with 5 additions and 12 deletions.
diff --git a/src/main/java/io/github/ititus/commons/math/graph/DiGraph.java b/src/main/java/io/github/ititus/commons/math/graph/DiGraph.java
@@ -51,9 +51,7 @@ public Edge<T> addEdge(Vertex<T> start, Vertex<T> end) {
     }
 
     public Edge<T> addEdge(Vertex<T> start, Vertex<T> end, BigRational weight) {
-        if (Objects.requireNonNull(start).equals(Objects.requireNonNull(end))) {
-            throw new IllegalArgumentException("start=end");
-        } else if (getEdgeByVertices(start, end).isPresent()) {
+        if (getEdgeByVertices(Objects.requireNonNull(start), Objects.requireNonNull(end)).isPresent()) {
             throw new IllegalArgumentException("edge already exists");
         } else if (!Objects.requireNonNull(weight).isPositive()) {
             throw new IllegalArgumentException("weight");

diff --git a/src/main/java/io/github/ititus/commons/math/graph/Edge.java b/src/main/java/io/github/ititus/commons/math/graph/Edge.java
@@ -1,7 +1,6 @@
 package io.github.ititus.commons.math.graph;
 
 import io.github.ititus.commons.math.number.BigRational;
-import io.github.ititus.commons.math.number.BigRationalConstants;
 
 import java.util.Objects;
 
@@ -16,14 +15,12 @@ public final class Edge<T> {
     private final BigRational weight;
 
     Edge(Vertex<T> start, Vertex<T> end, BigRational weight) {
-        if (Objects.requireNonNull(start).equals(Objects.requireNonNull(end))) {
-            throw new IllegalArgumentException("start=end");
-        } else if (Objects.requireNonNull(weight).compareTo(BigRationalConstants.ZERO) <= 0) {
+        if (!Objects.requireNonNull(weight).isPositive()) {
             throw new IllegalArgumentException("weight");
         }
 
-        this.start = start;
-        this.end = end;
+        this.start = Objects.requireNonNull(start);
+        this.end = Objects.requireNonNull(end);
         this.weight = weight;
     }
 

diff --git a/src/main/java/io/github/ititus/commons/math/graph/Graph.java b/src/main/java/io/github/ititus/commons/math/graph/Graph.java
@@ -52,9 +52,7 @@ public Edge<T> addEdge(Vertex<T> start, Vertex<T> end) {
     }
 
     public Edge<T> addEdge(Vertex<T> start, Vertex<T> end, BigRational weight) {
-        if (Objects.requireNonNull(start).equals(Objects.requireNonNull(end))) {
-            throw new IllegalArgumentException("start=end");
-        } else if (getEdgeByVertices(start, end).isPresent()) {
+        if (getEdgeByVertices(Objects.requireNonNull(start), Objects.requireNonNull(end)).isPresent()) {
             throw new IllegalArgumentException("edge already exists");
         } else if (!Objects.requireNonNull(weight).isPositive()) {
             throw new IllegalArgumentException("weight");