<p dir="auto">I need to check in more detail, but my first impression is that supporting a <code class="notranslate">precomputed</code> metric doesn't involve too much modification to the existing code.</p>
<p dir="auto">Is there a reason we should not support it?</p>
<p dir="auto">OPTICS relies on the nearest neighbor graph, and should be possible to perform with precomputed distances (maybe it does already, but I don't think it's tested), and with sparse feature spaces. It should perhaps also be possible to perform with sparse precomputed neighborhoods (e.g. as returned from <code class="notranslate">radius_neighbors_graph(radius=max_bound)</code>) but I've not double checked this.</p>