d FFTW 3 is in the
planning/execution division of labor.  In FFTW 2, plans were found for a
given transform size and type, and then could be applied to <em>any</em>
arrays and for <em>any</em> multiplicity/stride parameters.  In FFTW 3,
you specify the particular arrays, stride parameters, etcetera when
creating the plan, and the plan is then executed for <em>those</em> arrays
(unless the guru interface is used) and <em>those</em> parameters
<em>only</em>.  (FFTW 2 had &ldquo;specific planner&rdquo; routine