25 lines
849 B
Java
25 lines
849 B
Java
package com.twitter.search.common.relevance.features;
|
|
|
|
import com.google.common.base.Preconditions;
|
|
|
|
/**
|
|
* Scoring utilities
|
|
*/
|
|
public final class ScoringUtils {
|
|
private ScoringUtils() { }
|
|
|
|
/**
|
|
* normalize a positive value of arbitrary range to [0.0, 1.0], with a slop
|
|
* @param value the value to normalize.
|
|
* @param halfval a reference value that will be normalized to 0.5
|
|
* @param exp an exponential parameter (must be positive) to control the converging speed,
|
|
* the smaller the value the faster it reaches the halfval but slower it reaches the maximum.
|
|
* @return a normalized value
|
|
*/
|
|
public static float normalize(float value, double halfval, double exp) {
|
|
Preconditions.checkArgument(exp > 0.0 && exp <= 1.0);
|
|
return (float) (Math.pow(value, exp) / (Math.pow(value, exp) + Math.pow(halfval, exp)));
|
|
}
|
|
|
|
}
|