src/sicp/ex2_34.clj

   1 (ns sicp.ex2_34
   2   (:use [clojure.test]
   3         [sicp [ch2-2 :only (accumulate)]]))
   4
   5 ;; horner's rule. Extensively used in signal processing world
   6 ;; Assume that the coefficients of the polynomial are arranged
   7 ;; in a sequence, from a0 through an.
   8 (defn horner-eval [x coeff-seq]
   9   (accumulate (fn [this-coeff higher-terms]
  10                 (+ this-coeff
  11                    (* x higher-terms)))
  12               0
  13               coeff-seq))
  14
  15 ;; 1 + 3x + 5x^3 + x^5 at x = 2
  16 (deftest test-horners-poly
  17   (is [= (horner-eval 2 '(1 3 0 5 0 1))
  18          79]))