PLINQ optimizations

README.md

@@ -47,10 +47,10 @@ Number of words|Time to check all anagrams no longer than that|Time to solve "ea
 ---------------|----------------------------------------------|-------------------------|-----------------------------------|-------------------------|---------------------------------------------
 3|0.04s||||4560
 4|0.65s|||0.1s|7,431,984
-5|21s|0.3s|0.1s|0.6s|1,347,437,484
+5|19s|0.3s|0.1s|0.5s|1,347,437,484
-6|12.5 minutes|2.2s|0.4s|5.4s|58,405,904,844
+6|10.5 minutes|1.9s|0.35s|4.7s|58,405,904,844
-7|5 hours|12.5s|1.6s|35s|1,070,307,744,114
+7|3.2 hours|11s|1.4s|31.5s|1,070,307,744,114
-8|49 hours|46s|4.7s|2.5 minutes|10,893,594,396,594
+8|49 hours|40s|4.1s|2.1 minutes|10,893,594,396,594
 9||2.5 minutes|13s|9.5 minutes|70,596,864,409,954
 10||5 minutes|21s|17.5 minutes|314,972,701,475,754
 
@@ -61,8 +61,6 @@ For comparison, certain other solutions available on GitHub seem to require 3 ho
 Conditional compilation symbols
 ===============================
 
-* Define `SINGLE_THREADED` to use standard enumerables instead of ParallelEnumerable (useful for profiling).
-
 * Define `DEBUG`, or build in debug mode, to get the total number of anagrams (not optimized).
 
 Implementation notes

dotnet/WhiteRabbit/Constants.cs

@@ -5,5 +5,7 @@
         public const int PhrasesPerSet = WhiteRabbitUnmanagedBridge.MD5Unmanaged.PhrasesPerSet;
 
         public const int MaxNumberOfWords = 8;
+
+        public const int NumberOfThreads = 4;
     }
 }

dotnet/WhiteRabbit/StringsProcessor.cs

@@ -3,6 +3,7 @@
     using System;
     using System.Collections.Generic;
     using System.Linq;
+    using System.Threading.Tasks;
 
     internal sealed class StringsProcessor
     {
@@ -65,14 +66,18 @@
             var sums = this.VectorsProcessor.GenerateSequences();
 
             // converting sequences of vectors to the sequences of words...
-            var result = from sum in sums.AsParallel()
+            Parallel.ForEach(sums, new ParallelOptions { MaxDegreeOfParallelism = Constants.NumberOfThreads }, sum =>
-                   let filter = ComputeFilter(sum)
+            {
-                   let wordsVariants = this.ConvertVectorsToWordIndexes(sum)
+                var filter = ComputeFilter(sum);
-                   from wordsArray in Flattener.Flatten(wordsVariants)
+                var wordsVariants = this.ConvertVectorsToWordIndexes(sum);
-                   from phraseSet in this.ConvertWordsToPhrases(wordsArray, filter)
+                foreach (var wordsArray in Flattener.Flatten(wordsVariants))
-                   select phraseSet;
+                {
-
+                    foreach (var phraseSet in this.ConvertWordsToPhrases(wordsArray, filter))
-            result.ForAll(action);
+                    {
+                        action(phraseSet);
+                    }
+                }
+            });
         }
 
         public long GetPhrasesCount()