 (A_j)</span>
<span class="sd">    &quot;&quot;&quot;</span>
    <span class="n">NA</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">nan</span>
    <span class="n">pos_i</span> <span class="o">=</span> <span class="n">start_i</span>
    <span class="n">pos_j</span> <span class="o">=</span> <span class="n">start_j</span>
    <span class="n">mapping</span> <span class="o">=</span> <span class="p">[]</span>

    <span class="k">for</span> <span class="n">i</span>