title: Non-linear regression in C#
body: <p>I'm looking for a way to produce a non-linear (preferably quadratic) curve, based on a 2D data set, for predictive purposes. Right now I'm using my own implementation of ordinary least squares (OLS) to produce a linear trend, but my trends are much more suited to a curve model. The data I'm analysing is system load over time.</p>
  
  <p>Here's the equation that I'm using to produce my linear coefficients:</p>
  
  <p><img src="https://i.stack.imgur.com/9HEpU.png" alt="Ordinary Least Squares (OLS) formula"></p>
  
  <p>I've had a look at Math.NET Numerics and a few other libs, but they either provide <em>interpolation</em> instead of <em>regression</em> (which is of no use to me), or the code just doesn't work in some way.</p>
  
  <p>Anyone know of any free open source libs or code samples that can produce the coefficients for such a curve?</p>