home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Amiga Format CD 41
/
Amiga Format CD41 (1999-06)(Future Publishing)(GB)[!][issue 1999-07].iso
/
-seriously_amiga-
/
programming
/
other
/
scm
/
slib
/
determ.scm
< prev
next >
Wrap
Text File
|
1999-04-19
|
486b
|
15 lines
;"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))))