h in turn was adapted from <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">units</span><span class="special">/</span><span class="identifier">detail</span><span class="special">/</span><span class="identifier">utility</span><span class="special">.</span><span class="identifier">hpp</span></code> and <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">log</span><span c