pan class="o">.</span><span class="n">ones</span><span class="p">,</span>
                                              <span class="n">scalar_is_valid</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>

        <span class="bp">self</span><span class="o">.</span><span class="n">centers</span> <span class="o">=</span> <span class="n">Parameter</span><span class="p">(</span><span class="n">centers_init</span><span class="p">)</span>
        <span class="bp">self</span><span cl