Zend Framework
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Calculate query weights and build query scorers.
A Weight is constructed by a query Query->createWeight(). The sumOfSquaredWeights() method is then called on the top-level query to compute the query normalization factor Similarity->queryNorm(float). This factor is then passed to normalize(float). At this point the weighting is complete.

float
$_queryNorm= ''
Normalization factor.
This value is stored only for query expanation purpose and not used in any other place