From 84e246a963b248cd8f0a3299043a7071b32a9ede Mon Sep 17 00:00:00 2001
From: Quadro <Peter Boyle>
Date: Tue, 18 May 2021 16:36:29 -0400
Subject: [PATCH] Allow  dimensions to be periodic

---
 Grid/qcd/action/momentum/DirichletFilter.h | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/Grid/qcd/action/momentum/DirichletFilter.h b/Grid/qcd/action/momentum/DirichletFilter.h
index 86823282..1014d64e 100644
--- a/Grid/qcd/action/momentum/DirichletFilter.h
+++ b/Grid/qcd/action/momentum/DirichletFilter.h
@@ -55,15 +55,16 @@ struct DirichletFilter: public MomentumFilterBase<MomentaField>
     ////////////////////////////////////////////////////
     LatticeInteger coor(grid); 
     LatticeColourMatrix zz(grid); zz = Zero();
+    Coordinate Global=grid->GlobalDimensions();
     for(int mu=0;mu<Nd;mu++) {
-
-      // If costly could provide Grid earlier and precompute masks
-      LatticeCoordinate(coor,mu);
+      if ( (Block[mu] <= Global[mu]) && (Block[mu]>1) ) {
+	// If costly could provide Grid earlier and precompute masks
+	LatticeCoordinate(coor,mu);
       
-      auto P_mu = PeekIndex<LorentzIndex>(P, mu);
-      P_mu = where(mod(coor,Block[mu])==Integer(Block[mu]-1),zz,P_mu);
-      PokeIndex<LorentzIndex>(P, P_mu, mu);
-
+	auto P_mu = PeekIndex<LorentzIndex>(P, mu);
+	P_mu = where(mod(coor,Block[mu])==Integer(Block[mu]-1),zz,P_mu);
+	PokeIndex<LorentzIndex>(P, P_mu, mu);
+      }
     }
   }
 };