Add module for unit EM field

extras/Hadrons/Modules.hpp

@@ -13,6 +13,7 @@
 #include <Grid/Hadrons/Modules/MGauge/Random.hpp>
 #include <Grid/Hadrons/Modules/MGauge/StochEm.hpp>
 #include <Grid/Hadrons/Modules/MGauge/Unit.hpp>
+#include <Grid/Hadrons/Modules/MGauge/UnitEm.hpp>
 #include <Grid/Hadrons/Modules/MLoop/NoiseLoop.hpp>
 #include <Grid/Hadrons/Modules/MScalar/ChargedProp.hpp>
 #include <Grid/Hadrons/Modules/MScalar/FreeProp.hpp>

extras/Hadrons/Modules/MGauge/UnitEm.cc

@@ -0,0 +1,68 @@
+/*************************************************************************************
+
+Grid physics library, www.github.com/paboyle/Grid 
+
+Source file: extras/Hadrons/Modules/MGauge/StochEm.cc
+
+Copyright (C) 2015
+Copyright (C) 2016
+
+
+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/Hadrons/Modules/MGauge/UnitEm.hpp>
+
+using namespace Grid;
+using namespace Hadrons;
+using namespace MGauge;
+
+/******************************************************************************
+*                  TStochEm implementation                             *
+******************************************************************************/
+// constructor /////////////////////////////////////////////////////////////////
+TUnitEm::TUnitEm(const std::string name)
+: Module<NoPar>(name)
+{}
+
+// dependencies/products ///////////////////////////////////////////////////////
+std::vector<std::string> TUnitEm::getInput(void)
+{
+    return std::vector<std::string>();
+}
+
+std::vector<std::string> TUnitEm::getOutput(void)
+{
+    std::vector<std::string> out = {getName()};
+    
+    return out;
+}
+
+// setup ///////////////////////////////////////////////////////////////////////
+void TUnitEm::setup(void)
+{
+    env().registerLattice<EmField>(getName());
+}
+
+// execution ///////////////////////////////////////////////////////////////////
+void TUnitEm::execute(void)
+{
+    PhotonR photon();
+    EmField &a = *env().createLattice<EmField>(getName());
+    LOG(Message) << "Generating unit EM potential..." << std::endl;
+    photon.UnitField(a);
+}

extras/Hadrons/Modules/MGauge/UnitEm.hpp

@@ -0,0 +1,67 @@
+/*************************************************************************************
+
+Grid physics library, www.github.com/paboyle/Grid 
+
+Source file: extras/Hadrons/Modules/MGauge/StochEm.hpp
+
+Copyright (C) 2015
+Copyright (C) 2016
+
+
+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 */
+#ifndef Hadrons_MGauge_UnitEm_hpp_
+#define Hadrons_MGauge_UnitEm_hpp_
+
+#include <Grid/Hadrons/Global.hpp>
+#include <Grid/Hadrons/Module.hpp>
+#include <Grid/Hadrons/ModuleFactory.hpp>
+
+BEGIN_HADRONS_NAMESPACE
+
+/******************************************************************************
+ *                         StochEm                                 *
+ ******************************************************************************/
+BEGIN_MODULE_NAMESPACE(MGauge)
+
+class TUnitEm: public Module<NoPar>
+{
+public:
+    typedef PhotonR::GaugeField     EmField;
+    typedef PhotonR::GaugeLinkField EmComp;
+public:
+    // constructor
+    TUnitEm(const std::string name);
+    // destructor
+    virtual ~TUnitEm(void) = default;
+    // dependency relation
+    virtual std::vector<std::string> getInput(void);
+    virtual std::vector<std::string> getOutput(void);
+    // setup
+    virtual void setup(void);
+    // execution
+    virtual void execute(void);
+};
+
+MODULE_REGISTER_NS(UnitEm, TUnitEm, MGauge);
+
+END_MODULE_NAMESPACE
+
+END_HADRONS_NAMESPACE
+
+#endif // Hadrons_MGauge_UnitEm_hpp_

extras/Hadrons/modules.inc

@@ -6,6 +6,7 @@ modules_cc =\
   Modules/MGauge/Random.cc \
   Modules/MGauge/StochEm.cc \
   Modules/MGauge/Unit.cc \
+  Modules/MGauge/UnitEm.cc \
   Modules/MScalar/ChargedProp.cc \
   Modules/MScalar/FreeProp.cc \
   Modules/MScalar/ScalarVP.cc
@@ -26,6 +27,7 @@ modules_hpp =\
   Modules/MGauge/Random.hpp \
   Modules/MGauge/StochEm.hpp \
   Modules/MGauge/Unit.hpp \
+  Modules/MGauge/UnitEm.hpp \
   Modules/MLoop/NoiseLoop.hpp \
   Modules/MScalar/ChargedProp.hpp \
   Modules/MScalar/FreeProp.hpp \

lib/qcd/action/gauge/Photon.h

@@ -68,6 +68,7 @@ namespace QCD{
     void StochasticField(GaugeField &out, GridParallelRNG &rng);
     void StochasticField(GaugeField &out, GridParallelRNG &rng,
                          const GaugeLinkField &weight);
+    void UnitField(GaugeField &out);
   private:
     void invKHatSquared(GaugeLinkField &out);
     void zmSub(GaugeLinkField &out);
@@ -219,6 +220,23 @@ namespace QCD{
     
     out = real(out);
   }
+
+  template<class Gimpl>
+  void Photon<Gimpl>::UnitField(GaugeField &out)
+  {
+    auto               *grid = dynamic_cast<GridCartesian *>(out._grid);
+    const unsigned int nd = grid->_ndimension;
+    GaugeLinkField     r(grid);
+    
+    r = Complex(1.0,0.0);
+
+    for(int mu = 0; mu < nd; mu++)
+    {
+      pokeLorentz(out, r, mu);
+    }
+    
+    out = real(out);
+  }
 //  template<class Gimpl>
 //  void Photon<Gimpl>::FeynmanGaugeMomentumSpacePropagator_L(GaugeField &out,
 //                                                            const GaugeField &in)