title: error while calling org.apache.commons.math3.transform.FastFourierTransformer;
body: <p>I am new to programming in Java, and new to apach.commons.math3 library. 
  I want to use fft in order to transform time series into Fourier series.
  the time series is saved in array of double named input.
  I'm using the following line to call the transform  function:</p>
  
  <pre><code>Complex[] fourierSereis=FastFourierTransformer.transform(input,TransformType.FORWARD);
  </code></pre>
  
  <p>ButI get the following error:</p>
  
  <blockquote>
    <p>Cannot make a static reference to the non-static method
    transform(double[], TransformType) from the type
    FastFourierTransformer</p>
  </blockquote>
  
  <p>Can someone please explain me what does that error means and what should I do to make it work?</p>
  
  <p>Thank you </p>