class="n">i_symbols</span> <span class="o">=</span> <span class="nb">set</span><span class="p">(</span><span class="n">system</span><span class="o">.</span><span class="n">get_chemical_symbols</span><span class="p">())</span>
        <span class="n">distance_matrix</span> <span class="o">=</span> <span class="n">system</span><span class="o">.</span><span class="n">get_distance_matrix</span><span class="p">()</span>

        <span class="c1"># Gather atomic numbers and symbols</span>
        <span class="n">