From aab27a655a6450a0685050291258fccbea177a9c Mon Sep 17 00:00:00 2001
From: Peter Boyle <paboyle@ph.ed.ac.uk>
Date: Mon, 14 May 2018 19:41:17 -0400
Subject: [PATCH] Start of GPU kernels

---
 lib/qcd/action/fermion/WilsonKernelsGpu.cc | 176 +++++++++++++++++++++
 1 file changed, 176 insertions(+)
 create mode 100644 lib/qcd/action/fermion/WilsonKernelsGpu.cc

diff --git a/lib/qcd/action/fermion/WilsonKernelsGpu.cc b/lib/qcd/action/fermion/WilsonKernelsGpu.cc
new file mode 100644
index 00000000..6bc01386
--- /dev/null
+++ b/lib/qcd/action/fermion/WilsonKernelsGpu.cc
@@ -0,0 +1,176 @@
+/*************************************************************************************
+
+Grid physics library, www.github.com/paboyle/Grid
+
+Source file: ./lib/qcd/action/fermion/WilsonKernelsGpu.cc
+
+Copyright (C) 2018
+
+Author: Peter Boyle <paboyle@ph.ed.ac.uk>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+See the full license in the file "LICENSE" in the top level distribution
+directory
+*************************************************************************************/
+/*  END LEGAL */
+#include <Grid/qcd/action/fermion/FermionCore.h>
+
+NAMESPACE_BEGIN(Grid);
+
+//////////////////////////////////////////////////////////////
+// Gpu implementation; view code at a premium and less unroll
+//////////////////////////////////////////////////////////////
+  
+#define GPU_STENCIL_LEG_PROJ(Dir,spProj)			\
+  if (SE->_is_local) {						\
+    spProj(chi, in[SE->_offset]);				\
+    if (SE->_permute) {						\
+      permute(tmp, chi, ptype);					\
+      chi = tmp;						\
+    }								\
+  } else {							\
+    chi = buf[SE->_offset];					\
+  }								
+
+#define GPU_STENCIL_LEG_RECON(Recon)  Recon(result, Uchi);
+// Xp is mu= 0
+template <class Impl>
+accelerator void WilsonKernels<Impl>::GpuDhopSiteDag(StencilView &st, DoubledGaugeFieldView &U,
+						     SiteHalfSpinor *buf, int sF,
+						     int sU, const FermionFieldView &in, FermionFieldView &out)
+{
+  SiteHalfSpinor tmp;
+  SiteHalfSpinor chi;
+  SiteHalfSpinor Uchi;
+  SiteSpinor result;
+  StencilEntry *SE;
+  int ptype;
+
+  for(int mu=0;mu<2*Nd;mu++) {
+
+    SE = st.GetEntry(ptype, mu, sF);
+
+    switch(mu){
+    case Xp:
+      GPU_STENCIL_LEG_PROJ(Xp,spProjXp); break;
+    case Yp:
+      GPU_STENCIL_LEG_PROJ(Yp,spProjYp); break;
+    case Zp:
+      GPU_STENCIL_LEG_PROJ(Zp,spProjZp); break;
+    case Tp:
+      GPU_STENCIL_LEG_PROJ(Tp,spProjTp); break;
+    case Xm:
+      GPU_STENCIL_LEG_PROJ(Xm,spProjXm); break;
+    case Ym:
+      GPU_STENCIL_LEG_PROJ(Ym,spProjYm); break;
+    case Zm:
+      GPU_STENCIL_LEG_PROJ(Zm,spProjZm); break;
+    case Tm:
+    default:
+      GPU_STENCIL_LEG_PROJ(Tm,spProjTm); break;
+    }
+
+    Impl::multLink(Uchi, U[sU], chi, mu, SE, st);	
+
+    switch(mu){
+    case Xp:
+      spReconXp(result, Uchi);    break;
+    case Yp:
+      accumReconYp(result, Uchi); break;
+    case Zp:
+      accumReconZp(result, Uchi); break;
+    case Tp:
+      accumReconTp(result, Uchi); break;
+    case Xm:
+      accumReconXm(result, Uchi); break;
+    case Ym:
+      accumReconYm(result, Uchi); break;
+    case Zm:
+      accumReconZm(result, Uchi); break;
+    case Tm:
+    default:
+      accumReconTm(result, Uchi); break;
+    }
+  }
+  vstream(out[sF], result);
+};
+
+template <class Impl>
+accelerator void WilsonKernels<Impl>::GpuDhopSite(StencilView &st, DoubledGaugeFieldView &U,
+						  SiteHalfSpinor *buf, int sF,
+						  int sU, const FermionFieldView &in, FermionFieldView &out) 
+{
+  SiteHalfSpinor tmp;
+  SiteHalfSpinor chi;
+  SiteHalfSpinor Uchi;
+  SiteSpinor result;
+  StencilEntry *SE;
+  int ptype;
+  
+  for(int mu=0;mu<2*Nd;mu++) {
+ 
+    SE = st.GetEntry(ptype, mu, sF);
+
+    switch(mu){
+    case Xp:
+      GPU_STENCIL_LEG_PROJ(Xp,spProjXm); break;
+    case Yp:
+      GPU_STENCIL_LEG_PROJ(Yp,spProjYm); break;
+    case Zp:
+      GPU_STENCIL_LEG_PROJ(Zp,spProjZm); break;
+    case Tp:
+      GPU_STENCIL_LEG_PROJ(Tp,spProjTm); break;
+    case Xm:
+      GPU_STENCIL_LEG_PROJ(Xm,spProjXp); break;
+    case Ym:
+      GPU_STENCIL_LEG_PROJ(Ym,spProjYp); break;
+    case Zm:
+      GPU_STENCIL_LEG_PROJ(Zm,spProjZp); break;
+    case Tm:
+    default:
+      GPU_STENCIL_LEG_PROJ(Tm,spProjTp); break;
+    }
+
+    Impl::multLink(Uchi, U[sU], chi, mu, SE, st);	
+
+    switch(mu){
+    case Xp:
+      spReconXm(result, Uchi); break;
+    case Yp:
+      accumReconYm(result, Uchi); break;
+    case Zp:
+      accumReconZm(result, Uchi); break;
+    case Tp:
+      accumReconTm(result, Uchi); break;
+    case Xm:
+      accumReconXp(result, Uchi); break;
+    case Ym:
+      accumReconYp(result, Uchi); break;
+    case Zm:
+      accumReconZp(result, Uchi); break;
+    case Tm:
+    default:
+      accumReconTp(result, Uchi); break;
+    }
+  }
+  vstream(out[sF], result);
+
+};
+
+FermOpTemplateInstantiate(WilsonKernels);
+
+NAMESPACE_END(Grid);
+