/// The query matches all documents, and scores each document according to the numeric /// value of that field. ///
/// It is assumed, and expected, that: ///
/// Combining this query in a FunctionQuery allows much freedom in affecting document scores. /// Note, that with this freedom comes responsibility: it is more than likely that the /// default Lucene scoring is superior in quality to scoring modified as explained here. /// However, in some cases, and certainly for research experiments, this capability may turn useful. ///
/// When contructing this query, select the appropriate type. That type should match the data stored in the /// field. So in fact the "right" type should be selected before indexing. Type selection /// has effect on the RAM usage: ///
/// Caching: /// Values for the numeric field are loaded once and cached in memory for further use with the same IndexReader. /// To take advantage of this, it is extremely important to reuse index-readers or index-searchers, /// otherwise, for instance if for each query a new index reader is opened, large penalties would be /// paid for loading the field values into memory over and over again! /// ///
/// WARNING: The status of the search.function package is experimental. /// The APIs introduced here might change in the future and will not be /// supported anymore in such a case. ///
/// The type selected at search search time should match the data stored in the field. /// Different types have different RAM requirements: ///
/// The type
param tells how to parse the field string values into a numeric score value.
///