is it possible to change the way score from different field combine to give final lucene score

[Nizamul]

Suppose I have two field field1 and field2 and let the score for a query from 
field1 and field2 are score1 and score2 respectively.now when computing the 
final lucene score I instead of score1,I want to use some function (f(score1)) 
of that score.