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Merged
merged 17 commits into from
Sep 9, 2019
Merged

Minor changes to euclidean algorithm implementation in Common Lisp #609

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7b5c628
Added a proof for the Euclidean Algorithm
Trashtalk217 May 31, 2019
131ae54
Revert "Added a proof for the Euclidean Algorithm"
Trashtalk217 May 31, 2019
74d7f61
Added docstrings and changed some code for brevity
Trashtalk217 Jun 6, 2019
5c4dc6b
Slightly changed the .md file to fit the changes.
Trashtalk217 Jun 10, 2019
2909c78
Changed the filename to be shorter
Trashtalk217 Jun 10, 2019
44e5523
Fixed the namechange to work
Trashtalk217 Jun 10, 2019
6612af5
Revert "Fixed the namechange to work"
Trashtalk217 Jun 10, 2019
7ed7602
Fixed the namechange to work again
Trashtalk217 Jun 10, 2019
cbe7585
update
Trashtalk217 Jul 8, 2019
58efad6
Changed indentations
Trashtalk217 Jul 17, 2019
ca7c648
changed a comment
Trashtalk217 Jul 17, 2019
db00304
Added newline at the end
Trashtalk217 Jul 17, 2019
4237b88
update
Trashtalk217 Jul 19, 2019
e1953bb
changed the euclid-sub function and fixed issues
Trashtalk217 Sep 8, 2019
a4cb76c
fixed indentation, and changed .md file
Trashtalk217 Sep 8, 2019
8e07794
update
Trashtalk217 Sep 8, 2019
329f333
update
Trashtalk217 Sep 8, 2019
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30 changes: 30 additions & 0 deletions contents/euclidean_algorithm/code/clisp/euclidean.lisp
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Original file line number Diff line number Diff line change
@@ -0,0 +1,30 @@
;;;; Euclidean algorithm implementation in Common Lisp

(defun euclid-sub (a b)
"Finds the greatest common divsor for any two integers"
(defun euclid-sub* (a b)
"Finds the greatest common divisor for any two positive integers"
(if (eql a b)
a
(if (> a b)
(euclid-sub* (- a b) b)
(euclid-sub* a (- b a)))))
(euclid-sub* (abs a) (abs b)))

(defun euclid-mod (a b)
"Finds the greatest common divisor for any two integers"
(if (zerop b)
(abs a)
(euclid-mod b (mod a b))))

(print (euclid-sub (* 64 67) (* 64 81)))
(print (euclid-mod (* 128 12) (* 128 77)))

;; Quick test
(assert
(eql (euclid-sub (* 64 67) (* 64 81))
(gcd (* 64 67) (* 64 81))))

(assert
(eql (euclid-mod (* 64 67) (* 64 81))
(gcd (* 64 67) (* 64 81))))
33 changes: 0 additions & 33 deletions contents/euclidean_algorithm/code/clisp/euclidean_algorithm.lisp
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6 changes: 3 additions & 3 deletions contents/euclidean_algorithm/euclidean_algorithm.md
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Expand Up @@ -20,7 +20,7 @@ The algorithm is a simple way to find the *greatest common divisor* (GCD) of two
{% sample lang="js" %}
[import:15-29, lang="javascript"](code/javascript/euclidean_example.js)
{% sample lang="lisp" %}
[import:3-12, lang="lisp"](code/clisp/euclidean_algorithm.lisp)
[import:3-12, lang="lisp"](code/clisp/euclidean.lisp)
{% sample lang="py" %}
[import:11-22, lang="python"](code/python/euclidean_example.py)
{% sample lang="haskell" %}
Expand Down Expand Up @@ -102,7 +102,7 @@ Modern implementations, though, often use the modulus operator (%) like so
{% sample lang="js" %}
[import:1-13, lang="javascript"](code/javascript/euclidean_example.js)
{% sample lang="lisp" %}
[import:13-17, lang="lisp"](code/clisp/euclidean_algorithm.lisp)
[import:14-18, lang="lisp"](code/clisp/euclidean.lisp)
{% sample lang="py" %}
[import:1-9, lang="python"](code/python/euclidean_example.py)
{% sample lang="haskell" %}
Expand Down Expand Up @@ -195,7 +195,7 @@ Here's a video on the Euclidean algorithm:
{% sample lang="js" %}
[import, lang="javascript"](code/javascript/euclidean_example.js)
{% sample lang="lisp" %}
[import, lang="lisp"](code/clisp/euclidean_algorithm.lisp)
[import, lang="lisp"](code/clisp/euclidean.lisp)
{% sample lang="py" %}
[import, lang="python"](code/python/euclidean_example.py)
{% sample lang="haskell" %}
Expand Down