1 files changed, 27 insertions, 0 deletions
diff --git a/gnuradio-core/src/utils/permute.scm b/gnuradio-core/src/utils/permute.scm
new file mode 100644
index 000000000..23ddfc999
--- /dev/null
+++ b/gnuradio-core/src/utils/permute.scm
@@ -0,0 +1,27 @@
+(require 'common-list-functions)
+
+
+(define (permute lst)
+  (define (aux set head)
+    (cond ((null? set) head)
+	  (else
+	   (map (lambda (x)
+		  (aux (set-difference set (list x))
+		       (cons x head)))
+		set))))
+  (aux lst '()))
+
+(define (permute-2 lst)
+  (let ((result '()))
+    (define (aux set head)
+      (if (null? set)
+	  (set! result (cons head result))
+	  (for-each (lambda (x)
+		      (aux (set-difference set (list x))
+			   (cons x head)))
+		    set)))
+    (aux lst '())
+    result))
+
+
+