From ee49c01d8663451c8200e998087cfb79283ecf82 Mon Sep 17 00:00:00 2001
From: Viktor Lofgren <vlofgren@marginalia.nu>
Date: Sat, 3 Aug 2024 14:47:23 +0200
Subject: [PATCH] (index) Tune ranking for verbatim matches in the title,
 rewarding shorter titles

---
 .../index/results/IndexResultScoreCalculator.java           | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/code/index/java/nu/marginalia/index/results/IndexResultScoreCalculator.java b/code/index/java/nu/marginalia/index/results/IndexResultScoreCalculator.java
index 74895cf2..aa414c1e 100644
--- a/code/index/java/nu/marginalia/index/results/IndexResultScoreCalculator.java
+++ b/code/index/java/nu/marginalia/index/results/IndexResultScoreCalculator.java
@@ -197,7 +197,7 @@ public class IndexResultScoreCalculator {
             temporalBias = 0;
         }
 
-        final int titleLength = spans.title.length();
+        final int titleLength = Math.max(1, spans.title.length());
 
         float coherenceScore = 0.f;
 
@@ -246,7 +246,9 @@ public class IndexResultScoreCalculator {
             coherenceScore = 0.75f * largestOptional;
         }
 
-        coherenceScore += (float) Math.pow(coherences.countOptional(positions) / (double) coherences.numOptional(), 2);
+        if (coherences.numOptional() > 0) {
+            coherenceScore += (float) Math.pow(coherences.countOptional(positions) / (double) coherences.numOptional(), 2);
+        }
 
         float[] weightedCounts = new float[compiledQuery.size()];
         int firstPosition = Integer.MAX_VALUE;