<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> T<span class="special">,</span> <span class="keyword">typename</span> F<span class="special">&gt;</span> 
      <a class="link" href="piecewise_line_idp82782016/param_type.html#idp82799088-bb"><span class="identifier">param_type</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">initializ