BIASVAL

The BIASVAL field specifier (case sensitive) allows you to bias the score of result documents by a specified percentage, based on whether they include a specific value in the specified field.

NOTE: You can optimize the speed of this field specifier by restricting the field to one of the following configuration options: 

Format

FieldText=BIASVAL{fieldValue,percentage}:fieldName
fieldValue

The value that the specified field must contain to increase or decrease the weight by the percentage. You can leave this value empty to apply a score change to any result document that does not have the specified field, or that has the field with an empty value.

percentage

A percentage in the range -100 to 100. The percentage (positive or negative) by which to boost the relevance of documents that have the value fieldValue in the field fieldName. (The boosted relevance score cannot be greater than 100% or less than -100%.)

When you set AbsWeight to True, this is the absolute value by which to boost the weight and it is then not limited by +/- 100.

fieldName The name of the field that must be present (and must contain the proper value) for the document relevance to be boosted.

NOTE: BIASVAL requires two arguments. BIASVAL{percentBoost}:fieldName is not valid syntax.

Examples

FieldText=BIASVAL{Cambridge,10}:TOWN

A document whose TOWN field value is Cambridge has its weighting increased by 10% (although the weighting cannot go over 100%).

FieldText=BIASVAL{Cambridge,10}:TOWN+BIASVAL{London,-10}:TOWN

A document whose TOWN field value is Cambridge has its weighting increased by 10%, and a document whose TOWN field value is London has its weighting decreased by 10%. This example shows that biases can be negative as well as positive, and that you can include more than one set of parameters with the specifier.

FieldText=BIASVAL{,-10}:COLOUR 

A document that does not have the COLOUR field, or that has a COLOUR field with an empty value, has its weighting decreased by 10%.

See Also