span class="emphasis"><em>n</em></span> filters, whose element each consist of <span class="emphasis"><em>p</em></span>
      summands, the complexity of the constructor call is O(<span class="emphasis"><em>n</em></span><sup>2</sup><span class="emphasis"><em>p</em></span>).
      This is not cheap-though for most cases small <span class="emphasis"><em>p</em></span> and <span class="emphasis"><em>n</em></span>
      not too large (&lt; 20) is desired. However, for concreteness, on the author's
      2.7GHz I