title: Sum of sine data fitting with mathematica
body: <p>Hy everyones,</p>
  
  <p>I've a little problem with a mathematica script which I need for fitting data points with a sum of 3 sine functions : </p>
  
  <pre><code>fit = NonlinearModelFit[Data,a1*Sin[b1*x + c1] + a2*Sin[b2*x + c2] + a3*Sin[b3*x + c3], {a1, b1,c1, a2, b2, c2, a3, b3, c3}, x]
  </code></pre>
  
  <p>I get this error :</p>
  
  <pre><code>NonlinearModelFit::cvmit: Failed to converge to the requested accuracy or precision within 100 iterations
  </code></pre>
  
  <p>I've tried with different starting values and with MaxIteration set to 10.000...
  Maybe it's not the right way to do this kind of fitting. Does anyone have an idea about this?</p>
  
  <p>Thanks!</p>