an id="Sublosses.window_diff-46"><a href="#Sublosses.window_diff-46"><span class="linenos">46</span></a>    <span class="c1"># Addup is the sum of the total error, masked.</span>
</span><span id="Sublosses.window_diff-47"><a href="#Sublosses.window_diff-47"><span class="linenos">47</span></a>    <span class="n">_a_masked</span> <span class="o">=</span> <span class="n">tf</span><span class="o">.</span><span class="n">linalg</span><span class="o">.</span><span class="n">matvec</span><span class="p">(</span><s