From 76c2fc1c863249b050a1cb536730e5829bc5e337 Mon Sep 17 00:00:00 2001
From: Andrew Johnson <andrew.johnson@arjohnsonau.com>
Date: Wed, 1 Jul 2026 17:17:41 +0800
Subject: [PATCH] Account for namespace changes in Eigen 5

---
 src/utils.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/utils.h b/src/utils.h
index 80f0fa627..decc31986 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -28,7 +28,9 @@ T1 subset_matrix(T1 input, T2 index1, T2 index2) {
 
 template <typename T1, typename T2>
 T1 subset_matrix(T1 input, T2 index1) {
-  #if EIGEN_VERSION_AT_LEAST(3,4,0)
+  #if EIGEN_VERSION_AT_LEAST(5,0,0)
+    T1 ret = input(index1, Eigen::indexing::all);
+  #elif EIGEN_VERSION_AT_LEAST(3,4,0)
     T1 ret = input(index1, Eigen::all);
   #else
     T1 ret(index1.size(), input.cols());