Merge pull request #3864 from vespa-engine/bratseth/document-averageFieldLength

Document averageFieldLength

Author: bratseth

en/reference/nativerank.html

@@ -922,6 +922,12 @@ <h2 id="configuration-properties">Configuration properties</h2>
 <thead>
 <tr><th>Feature</th><th>Parameter</th><th>Default</th><th>Description</th></tr>
 </thead><tbody>
+<tr>
+  <td><code>nativeFieldMatch</code></td>
+  <td><code>averageFieldLength</code></td>
+  <td>The actual length of the field in the given document.</td>
+  <td>When set this replaces the true field length in the nativeFieldMatch formula for all documents.</td>
+</tr><tr>
 <tr>
     <td><code>nativeFieldMatch</code></td>
     <td><code>firstOccurrenceTable</code></td>

en/reference/rank-feature-configuration.html

@@ -12,9 +12,9 @@
 
 
 
-<h2 id="variables">Variables</h2>
+<h2 id="properties">Properties</h2>
 <p>
-  Rank Features configuration variables are set by adding the following to the rank profile:
+  Rank Features configuration properties are set by adding the following to the rank profile:
 </p>
 <pre>
 rank-properties {
@@ -24,17 +24,13 @@ <h2 id="variables">Variables</h2>
 <p>
   Where <em>&lt;featurename&gt;</em> is the name of a feature class (feature name up to the first dot),
   <em>&lt;configuration-property&gt;</em> is a property from the list below,
-  appropriate for the feature, and <em>&lt;value&gt;</em> is either a number of a quoted string.
-  Example: set some properties on the fieldMatch and BM25 feature class of two different fields,
-  set properties for elementwise BM25 on the content field
-  and define custom outputs for the elementSimilarity feature for multivalued field ranking.
+  appropriate for the feature, and <em>&lt;value&gt;</em> is either a number of a quoted string. Example:
 </p>
 <pre>
-ranking-profile my-profile inherits default {
+rank-profile my-profile inherits default {
   rank-properties {
     fieldMatch(title).maxAlternativeSegmentations: 10
     fieldMatch(title).maxOccurrences: 5
-    fieldMatch(description).maxOccurrences: 20
     bm25(title).k1: 1.5
     bm25(title).b: 0.85
     bm25(title).averageFieldLength: 200
@@ -45,21 +41,18 @@ <h2 id="variables">Variables</h2>
     elementSimilarity(tags).output.avgWeightSquared: "avg((0.35*p+0.15*o+0.30*q+0.20*f)*w^2)"
     elementSimilarity(tags).output.sumWeight: "sum(w)"
   }
-  match-features {
-    elementSimilarity(tags).sumWeightSquared
-    elementSimilarity(tags).sumWeight
-    bm25(title)
-    elementwise(bm25(content),x,float)
-  }
 }
 </pre>
 <p>
-  Note that rank profiles can be inherited to use the same variables in multiple profiles.
+  Rank profiles are inherited like other content of rank profiles.
 </p>
 
 
 
-<h2 id="properties">Configuration Properties</h2>
+<h2 id="List of properties">List of properties</h2>
+
+<p>An incomplete list of rank properties by the feature they apply to.</p>
+
 <table class="table">
   <thead>
     <tr><th>Feature</th><th>Parameter</th><th>Default</th><th>Description</th></tr>
@@ -88,7 +81,8 @@ <h2 id="properties">Configuration Properties</h2>
       When using <a href="../streaming-search.html#differences-in-streaming-search">streaming search</a>,
       no index structures are generated, and the average field length is not automatically calculated.
       Instead, manually set an average field length for a more precise BM25 score.
-  </td></tr>
+  </td>
+</tr>
 
 <tr>
   <td rowspan="3">