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POProblem with Random and Threads in .NET
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copied!<p>I'm having trouble with the <a href="http://msdn.microsoft.com/en-us/library/system.random.aspx" rel="nofollow noreferrer">Random</a> class in .NET, I'm implementing a threaded collection which is working fine, except for one smaller detail. The collection is a <a href="http://en.wikipedia.org/wiki/Skip_list" rel="nofollow noreferrer">Skip list</a> and those of you familiar with it know that for every node inserted I need to generate a new height that is <code><= CurrentMaxHeight+1</code>, here's the code that I'm using to do that (I know it's very inefficient, but it works and thats my main priority now)</p> <pre><code>int randomLevel() { int height = 1; while(rnd.NextDouble() >= 0.5 && height < MaxHeight) ++height; return height; } </code></pre> <p>My problem here is that sometimes I keep getting only 1 back from this for several thousand elements in a row which kills the performance of the skip list. The chance for 10.000 elements to generate only 1 from this method in a row, seems very slim (happens pretty consistently).</p> <p>So I'm assuming <em>(guessing)</em> that there is a problem with the <code>Random</code> object in some way, but I don't really know where to start digging around. So I turn to stackoverflow to see if anyone has an idea?</p> <p><strong>Edit</strong></p> <p>The rnd-variable is declared in the class <code>SkipList<T></code>, and it is accessed from several threads (each thread calls .Add on the collection and Add calls .randomLevel)</p>

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