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POParallel.For in C#
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copied!<p>I am trying convert the following Collatz Conjecture algorithm from:</p> <pre><code> public class CollatzConjexture { public static int Calculate(int StartIndex, int MaxSequence) { int ChainLength = 0; int key = 0; bool ContinuteCalulating = true; int LongestChain = 0; Int64 Remainder = 0; for (int i = StartIndex; i <= MaxSequence; i++) { ChainLength = 1; Remainder = i; ContinuteCalulating = true; while (ContinuteCalulating) { Remainder = CalculateCollatzConjecture(Remainder); if (Remainder == 1) ContinuteCalulating = false; ChainLength += 1; } if (ChainLength > LongestChain) { LongestChain = ChainLength; key = i; } } return key; } private static Int64 CalculateCollatzConjecture(Int64 Number) { if (Number % 2 == 0) return Number / 2; else return (3 * Number) + 1; } } </code></pre> <p>To instead use the .NET 4.0 Parallel.For :</p> <pre><code>int ChainLength = 0; int key = 0; bool ContinuteCalulating = true; int LongestChain = 0; Int64 Remainder = 0; int[] nums = Enumerable.Range(1, 1500000).ToArray(); long total = 0; // Use type parameter to make subtotal a long, not an int Parallel.For<int>(1, nums.Length, () => 1, (j, loop, subtotal) => { Remainder = j; while (ContinuteCalulating) { Remainder = CalculateCollatzConjecture(Remainder); if (Remainder == 1) ContinuteCalulating = false; ChainLength += 1; } if (ChainLength > LongestChain) { LongestChain = ChainLength; key = j; } return key; }, (x) => Interlocked.Add(ref key, x) ); </code></pre> <p>I have a feeling I'm not too far from it, famous last words.</p> <p>Thanks in advance.</p>

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