From de8335daabffd52b66b67a872188cda49c048d3a Mon Sep 17 00:00:00 2001
From: Urs Ganse <urs.ganse@helsinki.fi>
Date: Wed, 29 Apr 2026 14:00:58 +0300
Subject: [PATCH] Change neighbor_index temp variable from char to int, for arm
 builds.

Turns out "char" is an unsigned type when building with nvcc on arm.
Whoever came up with that.
---
 fsgrid.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fsgrid.hpp b/fsgrid.hpp
index cb81473..c0da3c3 100644
--- a/fsgrid.hpp
+++ b/fsgrid.hpp
@@ -1136,7 +1136,7 @@ template <typename T, int stencil> class FsGrid : public FsGridTools{
       uint numRequests;
 
       std::array<int, 27> neighbour; //!< Tasks of the 26 neighbours (plus ourselves)
-      std::vector<char> neighbour_index; //!< Lookup table from rank to index in the neighbour array
+      std::vector<int> neighbour_index; //!< Lookup table from rank to index in the neighbour array
 
       // We have, fundamentally, two different coordinate systems we're dealing with:
       // 1) Task grid in the MPI_Cartcomm