        of freedom that might appear to be integral, are treated as real values (and
        are promoted from integer to floating-point if necessary). In this case however,
        that there are a small number of situations where non-integral degrees of
        freedom do have a genuine meaning.
      </p>
<p>
        Generally speaking there is no loss of performance from allowing real-values
        parameters: the underlying special functions contain optimizations for integer-valued
        arguments w