From 1ec8ff74642bd01a3e8ee75686d7801f477e5ec5 Mon Sep 17 00:00:00 2001
From: conrad <conrad@localhost.localdomain>
Date: Fri, 6 Oct 2023 13:19:22 +1000
Subject: [PATCH] minor optimisation

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

diff --git a/include/armadillo_bits/Mat_meat.hpp b/include/armadillo_bits/Mat_meat.hpp
index a96fbd9b..4cb8d765 100644
--- a/include/armadillo_bits/Mat_meat.hpp
+++ b/include/armadillo_bits/Mat_meat.hpp
@@ -2657,6 +2657,8 @@ Mat<eT>::operator=(const SpBase<eT, T1>& m)
   
   (*this).zeros(x.n_rows, x_n_cols);
   
+  if(x.n_nonzero == 0)  { return *this; }
+  
   const    eT* x_values      = x.values;
   const uword* x_row_indices = x.row_indices;
   const uword* x_col_ptrs    = x.col_ptrs;