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Diffstat (limited to 'net/ricketyspace/sicp/one/eight.scm')
-rw-r--r-- | net/ricketyspace/sicp/one/eight.scm | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/net/ricketyspace/sicp/one/eight.scm b/net/ricketyspace/sicp/one/eight.scm new file mode 100644 index 0000000..8157c23 --- /dev/null +++ b/net/ricketyspace/sicp/one/eight.scm @@ -0,0 +1,38 @@ +;;; Under Creative Commons Attribution-ShareAlike 4.0 +;;; International. See +;;; <https://creativecommons.org/licenses/by-sa/4.0/>. + +(define-module (net ricketyspace sicp one eight) + #:export (cube double + div-three improve + good-enough? cbrt-iter + cbrt-sicp)) + +(use-modules (one six)) + +(define (cube x) + (* (square x) x)) + +(define (double x) + (* 2 x)) + +(define (div-three x) + (/ x 3.0)) + +(define (improve y x) + (div-three (+ (/ x (square y)) + (double y)))) + +(define (good-enough? y x) + (< (abs (- (cube y) x)) + 0.001)) + +(define (cbrt-iter y x) + (if (good-enough? y x) + y + (cbrt-iter (improve y x) + x))) + +(define (cbrt-sicp x) + (cbrt-iter 1.0 x)) + |