 -function to within an absolute accuracy
 -function to within an absolute accuracy  is presented. Many unnecessary computations are avoided when it can be determined by Chernoff bounds that the desired function is within
 is presented. Many unnecessary computations are avoided when it can be determined by Chernoff bounds that the desired function is within  of 0 or 1. When this is not the case, efficient algorithms for the necessary computations are also provided.
 of 0 or 1. When this is not the case, efficient algorithms for the necessary computations are also provided.