From f24b9140d6f74804d5599ec225717d38ca443813 Mon Sep 17 00:00:00 2001
From: Bryan Newbold <bnewbold@robocracy.org>
Date: Mon, 20 Feb 2017 00:05:26 -0800
Subject: Import Upstream version 2c0

---
 determ.scm | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 determ.scm

(limited to 'determ.scm')

diff --git a/determ.scm b/determ.scm
new file mode 100644
index 0000000..4b53e5f
--- /dev/null
+++ b/determ.scm
@@ -0,0 +1,14 @@
+;"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))))
-- 
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