ransformed (signal)</dd><dd><code>type</code> - the type of transform (forward, inverse) to be performed</dd>
<dt><span class="strong">Returns:</span></dt><dd>the real transformed array (spectrum)</dd>
<dt><span class="strong">Throws:</span></dt>
<dd><code><a href="../../../../../org/apache/commons/math3/exception/MathIllegalArgumentException.html" title="class in org.apache.commons.math3.exception">MathIllegalArgumentException</a></code> - if the length of the data array is
 not a power of two</dd></dl>
</