diff --git a/linear-algebra/svd.lisp b/linear-algebra/svd.lisp
index 9cbae06cdbe33c2326bab483d2f8e8cf8d98fe30..c88cd8b6b2042f2f48cd8cc979f91ba8059c1a0d 100644
--- a/linear-algebra/svd.lisp
+++ b/linear-algebra/svd.lisp
@@ -101,7 +101,7 @@
    references for details).")
 
 (defmfun SV-solve
-    (U S V b &optional (x (make-marray 'double-float :dimensions (dim0 U))))
+    (U S V b &optional (x (make-marray 'double-float :dimensions (dim0 V))))
   "gsl_linalg_SV_solve"
   (((mpointer U) :pointer) ((mpointer V) :pointer)
    ((mpointer S) :pointer)