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authorJim Pick <jim@jimpick.com>1998-03-08 23:05:22 -0800
committerBryan Newbold <bnewbold@robocracy.org>2017-02-20 00:05:27 -0800
commitb21cac3362022718634f7086964208b2eed8e897 (patch)
tree16f4b2e70645c0e8e2202023170b5a94baa967e3 /determ.scm
parent3796d2595035e192ed4bf1c9a6bfdb13c3c9d261 (diff)
parentf24b9140d6f74804d5599ec225717d38ca443813 (diff)
downloadslib-b21cac3362022718634f7086964208b2eed8e897.tar.gz
slib-b21cac3362022718634f7086964208b2eed8e897.zip
Import Debian changes 2c0-3debian/2c0-3
slib (2c0-3) unstable; urgency=low * New maintainer. * slibconfig script to automatically configure guile. * Fix type in description, closes: Bug#18996 slib (2c0-2) unstable; urgency=low * Minor fix for debian/rules targets slib (2c0-1) unstable; urgency=low * New upstream source * New maintainer
Diffstat (limited to 'determ.scm')
-rw-r--r--determ.scm14
1 files changed, 14 insertions, 0 deletions
diff --git a/determ.scm b/determ.scm
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+;"determ.scm" Determinant
+
+(define (determinant m)
+ (define (butnth n lst)
+ (if (zero? n) (cdr lst) (cons (car lst) (butnth (+ -1 n) (cdr lst)))))
+ (define (minor m i j)
+ (map (lambda (x) (butnth j x)) (butnth i m)))
+ (define (cofactor m i j)
+ (* (if (odd? (+ i j)) -1 1) (determinant (minor m i j))))
+ (define n (length m))
+ (if (eqv? 1 n) (caar m)
+ (do ((j (+ -1 n) (+ -1 j))
+ (ans 0 (+ ans (* (list-ref (car m) j) (cofactor m 0 j)))))
+ ((negative? j) ans))))