title: Simple multidimensional curve fitting
body: <p>I have a bunch of data, generally in the form 
  a, b, c, ..., y</p>
  
  <p>where y = f(a, b, c...)</p>
  
  <p>Most of them are three and four variables, and have 10k - 10M records.  My general assumption is that they are algebraic in nature, something like:</p>
  
  <p>y = P1 a^E1 + P2 b^E2 + P3 c^E3 </p>
  
  <p>Unfortunately, my last statistical analysis class was 20 years ago.  What is the easiest way to get a good approximation of f?  Open source tools with a very minimal learning curve (i.e. something where I could get a decent approximation in an hour or so) would be ideal.  Thanks!</p>