</span><span class="o">.</span><span class="n">matrix</span><span class="p">[</span><span class="n">i</span><span class="p">]</span>

        <span class="c1"># compute mapping table</span>
        <span class="n">map_df</span> <span class="o">=</span> <span class="n">map_indices</span><span class="p">(</span>
            <span class="n">target_seq</span><span class="p">,</span> <span class="n">target_start</span><span class="p">,</span> <span class="n">target_end</span><span class="p">,</span>
            