diff --git a/optimise.h b/optimise.h
index 39b6b6abb92fa83b28f767ea68e1fb114fecd702..302f600d336b082bd8f7f4351c69d694c59974aa 100644
--- a/optimise.h
+++ b/optimise.h
@@ -27,7 +27,7 @@ float optimise1d(ColumnVector &pt, const ColumnVector dir,
 
  float optimise(ColumnVector &pt, int numopt, const ColumnVector &tol, 
 		float (*func)(const ColumnVector &), int &iterations_done, 
-		int max_iter, const ColumnVector& boundguess, const bool in_slice=false);
+		int max_iter, const ColumnVector& boundguess);
 
 }