span class="mi">1</span> <span class="o">/</span> <span class="n">grid_points</span><span class="p">)</span> <span class="o">*</span>
            <span class="n">np</span><span class="o">.</span><span class="n">sum</span><span class="p">(</span>
                <span class="n">np</span><span class="o">.</span><span class="n">square</span><span class="p">(</span>
                    <span class="n">fcst</span><span class="p">[</span>
                        <span class="n">i</span><span class="p">,</span>
  