From: Ramakrishnan Muthukrishnan Date: Tue, 18 May 2010 13:19:00 +0000 (+0530) Subject: Solution to 1.38. I am generating the denominator in a little X-Git-Url: https://git.rkrishnan.org/components/com_hotproperty/%22doc.html/statistics?a=commitdiff_plain;h=ce74f5c80b1ee500e35ac6bf669cbe17f51beed0;p=sicp.git Solution to 1.38. I am generating the denominator in a little convoluted way. There should be a better mathematical way to generate the denominator sequence. --- diff --git a/src/sicp/ex1_38.clj b/src/sicp/ex1_38.clj new file mode 100644 index 0000000..54acde7 --- /dev/null +++ b/src/sicp/ex1_38.clj @@ -0,0 +1,34 @@ +(ns sicp.ex1_38 + (:use [sicp utils ex1_37] + [clojure.contrib test-is])) + +(defn gen-sequence [len] + (let [l (+ 1 (int (/ len 3))) + s1 (map #(* % 2) (range 1 (inc l))) + s2 (map (fn [_] 1) (range 1 (inc l)))] + (concat [0 1] (interleave s1 s2 s2)))) +;; we concat [0 1] because nth sequences are indexed from 0 + +;; approximating e +(defn e-approximation [len] + (let [l (* 3 (int (/ len 3.0))) + den (gen-sequence l)] + (+ 2.0 + (cont-frac (fn [k] 1.0) + (fn [k] (nth den k)) + l)))) + +(comment +user> (e-approximation 10) +2.718283582089552 +user> (e-approximation 20) +2.7182818284590278 +user> (e-approximation 40) +2.7182818284590455 +user> (e-approximation 50) +2.7182818284590455 +user> (e-approximation 60) +2.7182818284590455 +user> (e-approximation 100) +2.7182818284590455 +) \ No newline at end of file