From c4d3e7919315ee16d08af71e4906abb17e2411fa Mon Sep 17 00:00:00 2001
From: Ryan Hill <Ryan.Hill@ed.ac.uk>
Date: Thu, 29 Jan 2026 14:46:52 +0000
Subject: [PATCH] Add ET support for Lattice spin- and colour-traces

---
 Grid/qcd/QCD.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Grid/qcd/QCD.h b/Grid/qcd/QCD.h
index dbedfa7c49..5b35dc6461 100644
--- a/Grid/qcd/QCD.h
+++ b/Grid/qcd/QCD.h
@@ -596,16 +596,32 @@ template<int Index,class vobj> inline vobj transposeColour(const vobj &lhs){
 //////////////////////////////////////////
 // Trace lattice and non-lattice
 //////////////////////////////////////////
+#define GRID_UNOP(name)   name
+#define GRID_DEF_UNOP(op, name)						\
+  template <typename T1, typename std::enable_if<is_lattice<T1>::value||is_lattice_expr<T1>::value,T1>::type * = nullptr> \
+  inline auto op(const T1 &arg) ->decltype(LatticeUnaryExpression<GRID_UNOP(name),T1>(GRID_UNOP(name)(), arg)) \
+  {									\
+    return     LatticeUnaryExpression<GRID_UNOP(name),T1>(GRID_UNOP(name)(), arg); \
+  }
+
 template<int Index,class vobj>
 inline auto traceSpin(const Lattice<vobj> &lhs) -> Lattice<decltype(traceIndex<SpinIndex>(vobj()))>
 {
   return traceIndex<SpinIndex>(lhs);
 }
+
+GridUnopClass(UnaryTraceSpin, traceIndex<SpinIndex>(a));
+GRID_DEF_UNOP(traceSpin, UnaryTraceSpin);
+
 template<int Index,class vobj>
 inline auto traceColour(const Lattice<vobj> &lhs) -> Lattice<decltype(traceIndex<ColourIndex>(vobj()))>
 {
   return traceIndex<ColourIndex>(lhs);
 }
+
+GridUnopClass(UnaryTraceColour, traceIndex<ColourIndex>(a));
+GRID_DEF_UNOP(traceColour, UnaryTraceColour);
+
 template<int Index,class vobj>
 inline auto traceSpin(const vobj &lhs) -> Lattice<decltype(traceIndex<SpinIndex>(lhs))>
 {
@@ -617,6 +633,8 @@ inline auto traceColour(const vobj &lhs) -> Lattice<decltype(traceIndex<ColourIn
   return traceIndex<ColourIndex>(lhs);
 }
 
+#undef GRID_UNOP
+#undef GRID_DEF_UNOP
 //////////////////////////////////////////
 // Current types
 //////////////////////////////////////////