Merge pull request #35 from matiii/feature/i20-page-rank

i20 omit one loop

Author: matiii

src/Dijkstra.NET/Dijkstra.NET.csproj

@@ -2,11 +2,10 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard1.3;net40</TargetFrameworks>
-    <Version>1.2.0</Version>
+    <Version>1.2.1</Version>
     <Authors>Mateusz Mazurek</Authors>
     <Company />
     <Description>Graph processing library.</Description>
-    <PackageLicenseUrl>https://github.com/matiii/Dijkstra.NET/blob/master/LICENSE</PackageLicenseUrl>
     <PackageProjectUrl>https://github.com/matiii/Dijkstra.NET</PackageProjectUrl>
     <RepositoryUrl>https://github.com/matiii/Dijkstra.NET</RepositoryUrl>
     <PackageTags>graphs graph-theory dijkstra page-rank</PackageTags>

src/Dijkstra.NET/PageRank/PageRankExtensions.cs

@@ -15,17 +15,13 @@ public static PageRankResult CalculatePageRank(this IPageRankGraph graph, double
         {
             var pageRank = new Dictionary<uint, double>();
             var pageRankNext = new Dictionary<uint, double>();
-            
-            // 0
-            foreach (var node in graph)
-            {
-                pageRank[node.Key] = 1.0 / graph.NodesCount;
-            }
 
+            double initPr = 1.0 / graph.NodesCount;
+            
             // 1
             foreach (var node in graph)
             {
-                pageRankNext[node.Key] = (1 - d) / graph.NodesCount + d * node.Parents.Sum(x => pageRank[x.Key] / x.NumberOfEdges);
+                pageRankNext[node.Key] = (1 - d) / graph.NodesCount + d * node.Parents.Sum(x => initPr / x.NumberOfEdges);
             }
 
             // 2