From 1edb4c6d9abfd2856f74d5a53e8980dd087176e3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Adjemian=20=28Charybdis=29?=
 <stephane.adjemian@univ-lemans.fr>
Date: Thu, 5 Sep 2013 16:50:27 +0200
Subject: [PATCH] Added condition on dynSeries::lag method (input must be
 positive).

---
 matlab/@dynSeries/lag.m | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/matlab/@dynSeries/lag.m b/matlab/@dynSeries/lag.m
index c8499afaf..5258ce47e 100644
--- a/matlab/@dynSeries/lag.m
+++ b/matlab/@dynSeries/lag.m
@@ -44,6 +44,10 @@ if nargin<2
     p = 1;
 end
 
+if p<=0
+    error('dynSeries::lag: Second input argument must be strictly positive! Use lead method instead.')
+end
+
 % Copy of ts dynSeries object
 us = ts;