remove queryNorm computation

https://www.elastic.co/guide/en/elasticsearch/guide/current/practical-scoring-function.html#query-norm
weixsong · Feb 27, 2016 · 34a30ce · 34a30ce
1 parent 9c3de45
commit 34a30ce
Showing 1 changed file with 4 additions and 28 deletions.
diff --git a/lib/index.js b/lib/index.js
@@ -334,15 +334,13 @@ elasticlunr.Index.prototype.search = function (query, userConfig) {
   var queryTokens = this.pipeline.run(elasticlunr.tokenizer(query));
 
   var queryResults = {};
-  var squaredWeight = this.computeSquaredWeight(queryTokens, config);
 
   for (var field in config) {
     var fieldSearchResults = this.fieldSearch(queryTokens, field, config);
     var fieldBoost = config[field].boost;
-    var queryNorm = 1 / Math.sqrt(1 / (fieldBoost * fieldBoost) * squaredWeight);
 
     for (var docRef in fieldSearchResults) {
-      fieldSearchResults[docRef] = fieldSearchResults[docRef] * queryNorm;
+      fieldSearchResults[docRef] = fieldSearchResults[docRef] * fieldBoost;
     }
 
     for (var docRef in fieldSearchResults) {
@@ -389,9 +387,9 @@ elasticlunr.Index.prototype.fieldSearch = function (queryTokens, fieldName, conf
       for (var docRef in docs) {
         var tf = this.index[fieldName].getTermFrequency(key, docRef);
         var fieldLength = this.documentStore.getFieldLength(docRef, fieldName);
-        var norm = 1;
+        var fieldLengthNorm = 1;
         if (fieldLength != 0) {
-          norm = 1 / Math.sqrt(fieldLength);
+          fieldLengthNorm = 1 / Math.sqrt(fieldLength);
         }
 
         var penality = 1;
@@ -409,7 +407,7 @@ elasticlunr.Index.prototype.fieldSearch = function (queryTokens, fieldName, conf
           this.fieldSearchStats(docTokens, key, docs);
         }
 
-        var score = tf * idf * norm * penality;
+        var score = tf * idf * fieldLengthNorm * penality;
 
         if (docRef in scores) {
           scores[docRef] += score;
@@ -448,28 +446,6 @@ elasticlunr.Index.prototype.fieldSearchStats = function (docTokens, token, docs)
   }
 };
 
-/**
- * compute squared weight of query tokens.
- *
- * @param {Array} queryTokens query tokens.
- * @param {elasticlunr.Configuration} config The user query config, JSON format.
- * @return {Float}
- */
-elasticlunr.Index.prototype.computeSquaredWeight = function (queryTokens, config) {
-  var weight = 0.0;
-  queryTokens.forEach(function (token) {
-    var fieldWeight = 0.0;
-    for (var field in config) {
-      var fieldBoost = config[field].boost;
-      var idf = this.idf(token, field);
-      fieldWeight += idf * idf * fieldBoost * fieldBoost;
-    }
-    weight += fieldWeight;
-  }, this);
-
-  return weight;
-};
-
 /**
  * find documents contain all the query tokens.
  * only for inner use.