Minor improvements to neo4j post.

1 files changed, 14 insertions, 9 deletions

diff --git a/_log/neo4j-a-star-search.md b/_log/neo4j-a-star-search.md
index 017a33e..ad927e5 100644
--- a/_log/neo4j-a-star-search.md
+++ b/_log/neo4j-a-star-search.md
@@ -1,14 +1,19 @@
 ---
-title: 'Neo4J path traversal: A* optimization'
+title: 'Neo4J search: A* optimization'
 date: 2018-03-06
 layout: post
 ---
 
-Work. Vessel tracking with Neo4J hit a limit. Need to analyze 13,000 route
-points; Dijkstra's shortest path search slows after 4,000.
+Written in 2026, backdated to 2018. 
 
-Replaced Dijkstra's algorithm with A* search using haversine function as
-heuristic:
+First real performance problem. Vessel tracking with Neo4J hit a wall. Need to
+find shortest paths in a 13,000-vertex graph. Dijkstra's search, which Neo4J
+ships with, slowed to a crawl after 4,000.
+
+Spent better part of the week replacing Dijkstra's algorithm with A*
+search—Python shop, junior developer, took more than a day to set up toolchain
+and build the project. Haversine function as heuristic uses distance between
+ports as the crow flies to steer search:
 
 ```
 private double computeHeuristic(
@@ -47,10 +52,7 @@ private void updateCosts(
 }
 ```
 
-300x speedup. Scaled to 13,000 route points. 
-
-Despite impressive speedup, performance horizon visible. Unlikely to scale past
-16,000 points.
+Verdict: 300x speedup—scaled to 13,000 vertices.
 
 Upstreamed changes: <a
 href="https://github.com/neo4j-contrib/neo4j-graph-algorithms/releases/tag/3.4.0.0"
@@ -59,3 +61,6 @@ class="external" target="_blank" rel="noopener noreferrer">Neo4J v3.4.0</a> |
 href="https://github.com/neo4j-contrib/neo4j-graph-algorithms/blob/bd9732d9a690319552e134708692acb5a0d6b37c/algo/src/main/java/org/neo4j/graphalgo/impl/ShortestPathAStar.java"
 class="external" target="_blank" rel="noopener noreferrer">Full source</a>.
 
+NOTE: Despite impressive gain, performance horizon visible. Unlikely to scale past
+16,000 vertices without caching.
+