title: Signal processing library in Java?
body: <p>I'd like to compute power spectral density of time series; do some bandpass, lowpass, and highpass filtering; maybe some other basic stuff.</p>
  
  <p>Is there a nice open-source Java library to do this?</p>
  
  <p>I've hunted a bit without success (e.g., Googling "power spectral density java" or "signal processing java" and clicking through links, looking in Apache Commons, Sourceforge, java.net, etc.).</p>
  
  <p>There are lots of applets, books, tutorials, commercial products, etc., that don't meet my needs.</p>
  
  <p><b><i>Update</i></b>: I found <a href="http://commons.apache.org/proper/commons-math/userguide/transform.html" rel="noreferrer">org.apache.commons.math.transform</a> for Fourier transforms.  This doesn't implement power spectral density, bandpass, etc., but it is something.</p>