>dtype</span><span class="o">=</span><span class="s1">&#39;int32&#39;</span><span class="p">)</span>
        <span class="c1"># A global list of used indices across time samples and combinations.</span>
        <span class="c1"># Since there are no repetitive (z) indices across combinations, a global list can be used.</span>
        <span class="n">used</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([],</span> <span class="n">dty