<span class="pre">cache_location</span></code>.
In the above example <code class="docutils literal"><span class="pre">loc[above]</span></code> for simple interleaved images amounts to a
raw array index operator.</p>
</div>
<div class="section" id="iterator-over-2d-image">
<h2><a class="toc-backref" href="#id3">Iterator over 2D image</a></h2>
<p>Sometimes we want to perform the same, location-independent operation
over all pixels of an image. In such a case it is useful to represent
the pixels as a one-dimen