https://curiouscoding.nl/tags/route-planning/Recent content in Route-Planning on CuriousCodingHugoenMon, 02 Mar 2026 00:00:00 +0100https://curiouscoding.nl/posts/cch/Mon, 02 Mar 2026 00:00:00 +0100https://curiouscoding.nl/posts/cch/<div class="ox-hugo-toc toc has-section-numbers"> <div class="heading">Table of Contents</div> <ul> <li><span class="section-num">1</span> <a href="#problem-statement-customizable-route-planning--crp" >Problem Statement: Customizable Route Planning (CRP)</a></li> <li><span class="section-num">2</span> <a href="#contraction-hierarchies--ch" >Contraction Hierarchies (CH)</a> <ul> <li><span class="section-num">2.1</span> <a href="#classic-contraction-hierarchies" ><em>Classic</em> Contraction Hierarchies</a></li> <li><span class="section-num">2.2</span> <a href="#customizable-contraction-hierarchies--cch" ><em>Customizable</em> Contraction Hierarchies (CCH)</a></li> </ul> </li> <li><span class="section-num">3</span> <a href="#analogy-with-trees" >Analogy with trees</a></li> <li><span class="section-num">4</span> <a href="#shortest-paths-in-chs" >Shortest Paths in CHs</a></li> <li><span class="section-num">5</span> <a href="#parents-faster-shortest-paths-in-cchs" >Parents: Faster Shortest Paths in CCHs</a></li> <li><span class="section-num">6</span> <a href="#input-graph" >Input Graph</a></li> <li><span class="section-num">7</span> <a href="#initial-algorithm" >Initial Algorithm</a> <ul> <li><span class="section-num">7.1</span> <a href="#permute-input" >Permute input</a></li> <li><span class="section-num">7.2</span> <a href="#chordal-completion-and-parents" >Chordal Completion and Parents</a></li> <li><span class="section-num">7.3</span> <a href="#customize" >Customize</a></li> <li><span class="section-num">7.4</span> <a href="#query" >Query</a></li> </ul> </li> <li><span class="section-num">8</span> <a href="#optimizing-things" >Optimizing things</a> <ul> <li><span class="section-num">8.1</span> <a href="#binary-searching-in-find-edge" >Binary searching in <code>find_edge</code></a></li> <li><span class="section-num">8.2</span> <a href="#hashmap-of-edges" ><code>HashMap</code> of edges</a></li> <li><span class="section-num">8.3</span> <a href="#ranges-of-neighbours" >Ranges of neighbours</a></li> <li><span class="section-num">8.4</span> <a href="#linear-scan" >Linear scan</a></li> <li><span class="section-num">8.5</span> <a href="#proper-query-algorithm" >Proper query algorithm</a></li> <li><span class="section-num">8.6</span> <a href="#pruning-edges" >Pruning edges</a></li> <li><span class="section-num">8.7</span> <a href="#pruning" >Pruning</a></li> <li><span class="section-num">8.8</span> <a href="#unconditional-edge-relaxing" >Unconditional edge relaxing</a></li> <li><span class="section-num">8.9</span> <a href="#early-edge-break" >Early edge break</a></li> <li><span class="section-num">8.10</span> <a href="#dfs-ordering-the-nodes" >DFS-ordering the nodes</a></li> <li><span class="section-num">8.11</span> <a href="#not-inclining-queries" >Not inclining queries</a></li> </ul> </li> <li><span class="section-num">9</span> <a href="#some-stats" >Some stats</a></li> <li><span class="section-num">10</span> <a href="#serializing-the-final-structure" >Serializing the final structure</a></li> <li><span class="section-num">11</span> <a href="#merging-adjacent-edges" >Merging adjacent edges</a> <ul> <li><span class="section-num">11.1</span> <a href="#perf-stat" >Perf stat</a></li> <li><span class="section-num">11.2</span> <a href="#all-ranges-are-multiples-of-8" >All ranges are multiples of 8</a></li> <li><span class="section-num">11.3</span> <a href="#all-ranges-have-size-8" >All ranges have size 8</a></li> <li><span class="section-num">11.4</span> <a href="#finding-the-bottleneck" >Finding the bottleneck</a></li> </ul> </li> <li><span class="section-num">12</span> <a href="#bugfixing" >Bugfixing</a></li> <li><span class="section-num">13</span> <a href="#further-ideas" >Further ideas</a> <ul> <li><span class="section-num">13.1</span> <a href="#failed-doubling-the-graph" >Failed: Doubling the graph</a></li> <li><span class="section-num">13.2</span> <a href="#edge-pruning" >Edge pruning</a></li> <li><span class="section-num">13.3</span> <a href="#failed-expanding-a-node-and-its-parent-in-parallel" >Failed: Expanding a node and its parent in parallel</a></li> </ul> </li> <li><span class="section-num">14</span> <a href="#current-best-results" >Current best results</a> <ul> <li><span class="section-num">14.1</span> <a href="#bottleneck" >Bottleneck</a></li> </ul> </li> <li><span class="section-num">15</span> <a href="#d41d8c" ><span class="org-todo todo TODO">TODO</span> </a></li> </ul> </div> <!--endtoc--> <p>These are some notes on <em>customizable contraction hierarchies</em>, based on talks with Michael Zündorf and the survey paper by Bläsius, Buchhold, Wagner, Zeitz, and Zündorf (<a href="#citeproc_bib_item_1">2025</a>).</p>