Take instead of reverse drop

diff --git a/grad.scm b/grad.scm
index 315f4c0e61834ec8592abf26830e1036dbc44c63..5e1ea7fec84e4a992e5c10059ad0b30793e6e226 100644 (file)
--- a/grad.scm
+++ b/grad.scm
@@ -30,9 +30,9 @@
     (if (or (> n (array-rank a))
             (> n (array-rank b)))
       (error "can't contract arrays with size lower than" n)
-      (append (reverse (drop (reverse dims-a)
-                             n))
-              (drop dims-b n)))))
+      (append (take dims-a (- (array-rank a)
+                             n))
+             (drop dims-b n)))))
 
 (define (contract-arrays a b n)
   (let* ((dims (contracted-dims a b n))