From eef2a2706c7e36578cbfb360d1a60e7bf58aff75 Mon Sep 17 00:00:00 2001
From: conrad <conrad@localhost.localdomain>
Date: Tue, 6 Feb 2024 11:35:20 +1000
Subject: [PATCH] minor optimisation

---
 include/armadillo_bits/op_shift_meat.hpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/armadillo_bits/op_shift_meat.hpp b/include/armadillo_bits/op_shift_meat.hpp
index b369b5d3..216290b5 100644
--- a/include/armadillo_bits/op_shift_meat.hpp
+++ b/include/armadillo_bits/op_shift_meat.hpp
@@ -64,6 +64,8 @@ op_shift::apply_noalias(Mat<eT>& out, const Mat<eT>& X, const uword len, const u
   arma_debug_check_bounds( ((dim == 0) && (len >= X.n_rows)), "shift(): shift amount out of bounds" );
   arma_debug_check_bounds( ((dim == 1) && (len >= X.n_cols)), "shift(): shift amount out of bounds" );
   
+  if(len == 0)  { out = X; return; }
+  
   out.copy_size(X);
   
   const uword X_n_rows = X.n_rows;