[−][src]Module tantivy::fieldnorm
The fieldnorm represents the length associated to a given Field of a given document.
This metric is important to compute the score of a document : a document having a query word in one its short fields (e.g. title) is likely to be more relevant than in one of its longer field (e.g. body).
It encodes fieldnorm on one byte with some precision loss,
using the exact same scheme as Lucene. Each value is place on a log-scale
that takes values from 0 to 255.
A value on this scale is identified by a fieldnorm_id.
Apart from compression, this scale also makes it possible to
precompute computationally expensive functions of the fieldnorm
in a very short array.
This trick is used by the BM25 similarity.
Structs
| FieldNormReader | Reads the fieldnorm associated to a document. The fieldnorm represents the length associated to a given Field of a given document. |
| FieldNormsSerializer | The fieldnorms serializer is in charge of the serialization of field norms for all fields. |
| FieldNormsWriter | The |