/*************************************************************************************

Grid physics library, www.github.com/paboyle/Grid 

Source file: extras/Hadrons/Modules/MScalarSUN/TrPhi.hpp

Copyright (C) 2015-2018

Author: Antonin Portelli <antonin.portelli@me.com>

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_MScalarSUN_TrPhi_hpp_
#define Hadrons_MScalarSUN_TrPhi_hpp_

#include <Grid/Hadrons/Global.hpp>
#include <Grid/Hadrons/Module.hpp>
#include <Grid/Hadrons/ModuleFactory.hpp>
#include <Grid/Hadrons/Modules/MScalarSUN/Utils.hpp>

BEGIN_HADRONS_NAMESPACE

/******************************************************************************
 *                      Trace of powers of a scalar field                     *
 ******************************************************************************/
BEGIN_MODULE_NAMESPACE(MScalarSUN)

class TrPhiPar: Serializable
{
public:
    GRID_SERIALIZABLE_CLASS_MEMBERS(TrPhiPar,
                                    std::string,  field,
                                    unsigned int, maxPow,
                                    std::string,  output);
};

class TrPhiResult: Serializable
{
public:
    GRID_SERIALIZABLE_CLASS_MEMBERS(TrPhiResult,
                                    std::string, op,
                                    Real,        value);
};

template <typename SImpl>
class TTrPhi: public Module<TrPhiPar>
{
public:
    typedef typename SImpl::Field        Field;
    typedef typename SImpl::ComplexField ComplexField;

public:
    // constructor
    TTrPhi(const std::string name);
    // destructor
    virtual ~TTrPhi(void) {};
    // 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_TMP(TrPhiSU2, TTrPhi<ScalarNxNAdjImplR<2>>, MScalarSUN);
MODULE_REGISTER_TMP(TrPhiSU3, TTrPhi<ScalarNxNAdjImplR<3>>, MScalarSUN);
MODULE_REGISTER_TMP(TrPhiSU4, TTrPhi<ScalarNxNAdjImplR<4>>, MScalarSUN);
MODULE_REGISTER_TMP(TrPhiSU5, TTrPhi<ScalarNxNAdjImplR<5>>, MScalarSUN);
MODULE_REGISTER_TMP(TrPhiSU6, TTrPhi<ScalarNxNAdjImplR<6>>, MScalarSUN);

/******************************************************************************
 *                          TTrPhi implementation                             *
 ******************************************************************************/
// constructor /////////////////////////////////////////////////////////////////
template <typename SImpl>
TTrPhi<SImpl>::TTrPhi(const std::string name)
: Module<TrPhiPar>(name)
{}

// dependencies/products ///////////////////////////////////////////////////////
template <typename SImpl>
std::vector<std::string> TTrPhi<SImpl>::getInput(void)
{
    std::vector<std::string> in = {par().field};
    
    return in;
}

template <typename SImpl>
std::vector<std::string> TTrPhi<SImpl>::getOutput(void)
{
    std::vector<std::string> out;

    for (unsigned int n = 2; n <= par().maxPow; n += 2)
    {
        out.push_back(varName(getName(), n));
    }
    
    return out;
}

// setup ///////////////////////////////////////////////////////////////////////
template <typename SImpl>
void TTrPhi<SImpl>::setup(void)
{
    if (par().maxPow < 2)
    {
        HADRONS_ERROR(Size, "'maxPow' should be at least equal to 2");
    }
    envTmpLat(Field, "phi2");
    envTmpLat(Field, "buf");
    for (unsigned int n = 2; n <= par().maxPow; n += 2)
    {
        envCreateLat(ComplexField, varName(getName(), n));
    }
}

// execution ///////////////////////////////////////////////////////////////////
template <typename SImpl>
void TTrPhi<SImpl>::execute(void)
{
    LOG(Message) << "Computing tr(phi^n) for n even up to " << par().maxPow
                 << std::endl; 

    std::vector<TrPhiResult> result;
    auto                     &phi = envGet(Field, par().field);

    envGetTmp(Field, phi2);
    envGetTmp(Field, buf);
    buf  = 1.;
    phi2 = -phi*phi; 
    for (unsigned int n = 2; n <= par().maxPow; n += 2)
    {
        auto &phin = envGet(ComplexField, varName(getName(), n));

        buf  = buf*phi2;
        phin = trace(buf);
        if (!par().output.empty())
        {
            TrPhiResult r;

            r.op    = "tr(phi^" + std::to_string(n) + ")";
            r.value = TensorRemove(sum(phin)).real();
            result.push_back(r);
        }
    }
    if (result.size() > 0)
    {
        saveResult(par().output, "trphi", result);
    }
}

END_MODULE_NAMESPACE

END_HADRONS_NAMESPACE

#endif // Hadrons_MScalarSUN_TrPhi_hpp_