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Lextek Language Identifier
P_OR
Name
P_OR
Synopsis
Returns records where any the terms or subqueries are present.
Arguments
P-value
List of terms and subqueriesRanking Scheme
Ranks using the p-norm method. Conceptually you can consider each term a unique direction in n-space (where n is the number of terms). Each term's weight represents the distance in that direction. The p-value (p in the above formula) represents how much the final calculation is like the maximum weight or like the total distance of all vectors in n-space. For p = 2 the p-norm is identical to a vector space model. As p approaches infinity the returned weight becomes equal to the largest weight among the terms.
Picking an approrpiate p-value can be tricky and often is the result of experimentation. A simplified way of thinking about the calculation is that it varies between a kind of average weight to the maximum weight. Generally a p-value of 2.5 or 3 is effective.
The p-norm weighting method is one of the most effecient methods available, especially if you've been careful in choosing how you weight your terms.
The only terms included in the p-norm calculation for P_OR are those found in each record. Thus if you've indexed several documents as unique records you can have different weights for each one, depending upon which terms were present.
Comments
P_OR returns any hit for the terms or subqueries.
Example
P_OR( 'blue', 'green', 'red', 'orange', 'violet' );
See Also
any, or, value, r_or, p_or, m_or, atleast, atmost, r_atleast, r_atmost, p_atleast, p_atmost
