title: Trouble installing MathNet.Numerics in VS2010 Express, System.Numerics is missing?
body: <p>I'm new here, just getting my feet wet writing my first Windows Phone 7 app.  Specifically, I need to do linear regression on some data to get a simple y=Ax^2+Bx+C best fit curve.  After some searching I planned to use MathNet.Numerics, following the example I found.</p>
  
  <p>However, in the NuGet package manager when I run:
  PM> Install-Package MathNet.Numerics</p>
  
  <p>the installation fails, with the following error:</p>
  
  <p>Install-Package : Failed to add reference to 'System.Numerics'. Please make sure that it is in the Global Assembly Cache.</p>
  
  <p>At line:1 char:16</p>
  
  <ul>
  <li><p>Install-Package &lt;&lt;&lt;&lt;  MathNet.Numerics</p>
  
  <ul>
  <li>CategoryInfo          : NotSpecified: (:) [Install-Package], InvalidOperationException</li>
  <li>FullyQualifiedErrorId : uGetCmdletUnhandledException,NuGet.PowerShell.Commands.InstallPackageCommand</li>
  </ul></li>
  </ul>
  
  <p>I thought the first obvious step was to add System.Numerics to my project, but it does not exist in the "Add Reference" menu (or anywhere on my computer). I had thought it was included with .NET 4.0.  So I guess I have a few questions:</p>
  
  <ul>
  <li>Is my project configured incorrectly?  </li>
  <li>Is there a more official way to download System.Numerics than www.dllme.com? Or is that a normal way to get official Microsoft packages?</li>
  <li>Or, does anyone have suggestions for a light math library that would do simple linear regression?  I suppose I could stop being lazy and just write it myself, but I would rather use one that I know is written correctly. </li>
  </ul>
  
  <p>Thank you!</p>
  
  <p><strong>Edit:</strong>  So I've been kindly informed that System.Numerics does not exist for Windows phone.  I did some more searching and found this nicely written class to solve my problem, thought I'd throw the link up here in case anyone else finds it useful: 
  <a href="http://www.codeproject.com/Articles/63170/Least-Squares-Regression-for-Quadratic-Curve-Fitti" rel="nofollow">http://www.codeproject.com/Articles/63170/Least-Squares-Regression-for-Quadratic-Curve-Fitti</a></p>
  
  <p>I'm still a bit perplexed, as this official page seems to imply that MathNet.Numerics works great on Windows Phone.  I'd still be interested in getting that library working on a phone just to satisfy my curiosity:  <a href="http://msdn.microsoft.com/en-us/library/hh304363(v=vs.100).aspx" rel="nofollow">http://msdn.microsoft.com/en-us/library/hh304363(v=vs.100).aspx</a></p>