="sourceCode r"><span class="co"># combine results of front vs back illumination simulations (identical here, but anyway...)</span>
combined &lt;-<span class="st"> </span><span class="kw">data.frame</span>(<span class="dt">angle =</span> <span class="kw">c</span>(stack$angle, stack$angle +<span class="st"> </span>pi) *<span class="st"> </span><span class="dv">180</span>/pi,
                      <span class="dt">parallel =</span> <span class="kw">c</span>(M$Mr.par[[<span class="dv">1</span>]], M$Ml.par[[<sp