The BIAS
field specifier allows you to bias the score of results at query time according to the numerical proximity of the specified field to a particular value. It ignores initial dollar ($), pound sign (£), or hyphen (–) characters in the field names.
Specify BIAS
in the format:
BIAS{optimum,range,percentage}
where:
optimum
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is the value that the field must contain to increase or decrease the result weight by the maximum percentage . |
range
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is a positive number that determines the range of the optimum . If the specified field contains a value that is in the range of (optimum – range ) to (optimum + range ), the result weight increases or decreases according to the specified percentage . |
percentage
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is a percentage in the range –100 to 100 . If the value of the specified field is in the specified range, the score of the result increases or decreases according to how close the value is to the specified optimum . |
For example:
http://IDOLhost:port/action=Query&FieldText=BIAS{100,50,10}:*/PRICE
A document whose PRICE
field value is within the range 50 either side of 100 has its weight increased on a linear scale from 10 percent if the price is 100, to 0 percent if the price is 50 or 150:
http://IDOLhost:port/action=Query&FieldText=BIAS{100,50,-10}:*/PRICE
A document whose PRICE
field value is within the range 50 either side of 100 has its weight decreased on a linear scale from –10 percent if the price is 100, to 0 percent if the price is 50 or 150:
You can also use the BIAS
field specifier to bias the score of results according to the numerical proximity in their autn_date
metafield to a particular value. For example:
FieldText=BIAS{1103918400,259200,25}:autn_date
A document whose autn_date
field value is within the range 259200 either side of 1103918400 has its weight increased on a linear scale from 25 percent if the price is 1103918400, to 0 percent, if the date is 1103659200 or 1104177600.
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