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

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

Source file: extras/Hadrons/Modules/MContraction/A2AMesonField.hpp

Copyright (C) 2015-2018

Author: Antonin Portelli <antonin.portelli@me.com>
Author: Peter Boyle <paboyle@ph.ed.ac.uk>
Author: paboyle <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 */
#ifndef Hadrons_MContraction_A2AMesonField_hpp_
#define Hadrons_MContraction_A2AMesonField_hpp_

#include <Grid/Hadrons/Global.hpp>
#include <Grid/Hadrons/Module.hpp>
#include <Grid/Hadrons/ModuleFactory.hpp>
#include <Grid/Hadrons/A2AVectors.hpp>
#include <Grid/Hadrons/Modules/MSolver/A2AVectors.hpp>
#include <Grid/Hadrons/Modules/MContraction/A2AMesonFieldKernels.hpp>

#define MF_PARALLEL_IO

BEGIN_HADRONS_NAMESPACE

/******************************************************************************
 *                     All-to-all meson field creation                        *
 ******************************************************************************/
BEGIN_MODULE_NAMESPACE(MContraction)

class A2AMesonFieldPar: Serializable
{
  public:
    GRID_SERIALIZABLE_CLASS_MEMBERS(A2AMesonFieldPar,
                                    int, cacheBlock,
                                    int, block,
                                    std::string, v,
                                    std::string, w,
                                    std::string, output,
                                    std::string, gammas,
                                    std::vector<std::string>, mom);
};

template <typename FImpl>
class TA2AMesonField : public Module<A2AMesonFieldPar>
{
public:
    FERM_TYPE_ALIASES(FImpl,);
    SOLVER_TYPE_ALIASES(FImpl,);
public:
    // constructor
    TA2AMesonField(const std::string name);
    // destructor
    virtual ~TA2AMesonField(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);
private:
    // Arithmetic kernel. Move to Grid??
    void makeBlock(MesonField &mat, 
                   const FermionField *lhs,
                   const FermionField *rhs,
                   std::vector<Gamma::Algebra> gamma,
                   const std::vector<LatticeComplex> &mom,
                   int orthogdim,
                   double &t0,
                   double &t1,
                   double &t2,
                   double &t3);
    // IO
    std::string ioname(unsigned int m, unsigned int g) const;
    std::string filename(unsigned int m, unsigned int g) const;
    void initFile(unsigned int m, unsigned int g);
    void saveBlock(const MesonField &mf,
                   unsigned int m, unsigned int g, 
                   unsigned int i, unsigned int j);
private:
    bool                             hasPhase_{false};
    std::string                      momphName_;
    std::vector<Gamma::Algebra>      gamma_;
    std::vector<std::vector<double>> mom_;
    std::vector<std::pair<unsigned int, unsigned int>> nodeFile_;
};

MODULE_REGISTER(A2AMesonField, ARG(TA2AMesonField<FIMPL>), MContraction);
MODULE_REGISTER(ZA2AMesonField, ARG(TA2AMesonField<ZFIMPL>), MContraction);

/******************************************************************************
*                  TA2AMesonField implementation                             *
******************************************************************************/
// constructor /////////////////////////////////////////////////////////////////
template <typename FImpl>
TA2AMesonField<FImpl>::TA2AMesonField(const std::string name)
: Module<A2AMesonFieldPar>(name)
, momphName_(name + "_momph")
{
}

// dependencies/products ///////////////////////////////////////////////////////
template <typename FImpl>
std::vector<std::string> TA2AMesonField<FImpl>::getInput(void)
{
    std::vector<std::string> in = {par().v, par().w};

    return in;
}

template <typename FImpl>
std::vector<std::string> TA2AMesonField<FImpl>::getOutput(void)
{
    std::vector<std::string> out = {};

    return out;
}

// setup ///////////////////////////////////////////////////////////////////////
template <typename FImpl>
void TA2AMesonField<FImpl>::setup(void)
{
    gamma_.clear();
    mom_.clear();
    if (par().gammas == "all")
    {
        gamma_ = {
            Gamma::Algebra::Gamma5,
            Gamma::Algebra::Identity,    
            Gamma::Algebra::GammaX,
            Gamma::Algebra::GammaY,
            Gamma::Algebra::GammaZ,
            Gamma::Algebra::GammaT,
            Gamma::Algebra::GammaXGamma5,
            Gamma::Algebra::GammaYGamma5,
            Gamma::Algebra::GammaZGamma5,
            Gamma::Algebra::GammaTGamma5,
            Gamma::Algebra::SigmaXY,
            Gamma::Algebra::SigmaXZ,
            Gamma::Algebra::SigmaXT,
            Gamma::Algebra::SigmaYZ,
            Gamma::Algebra::SigmaYT,
            Gamma::Algebra::SigmaZT
        };
    }
    else
    {
        gamma_ = strToVec<Gamma::Algebra>(par().gammas);
    }
    for (auto &pstr: par().mom)
    {
        auto p = strToVec<Real>(pstr);

        if (p.size() != env().getNd() - 1)
        {
            HADRONS_ERROR(Size, "Momentum has " + std::to_string(p.size())
                                + " components instead of " 
                                + std::to_string(env().getNd() - 1));
        }
        mom_.push_back(p);
    }
    
    envCache(std::vector<LatticeComplex>, momphName_, 1, 
             par().mom.size(), env().getGrid());
    envTmpLat(LatticeComplex, "coor");
    // preallocate memory for meson field block
    auto tgp = env().getDim().back()*gamma_.size()*mom_.size();

    envTmp(Vector<Complex>, "mfBuf", 1, tgp*par().block*par().block);
    envTmp(Vector<Complex>, "mfCache", 1, tgp*par().cacheBlock*par().cacheBlock);
}

// execution ///////////////////////////////////////////////////////////////////
template <typename FImpl>
void TA2AMesonField<FImpl>::execute(void)
{
    auto &v = envGet(std::vector<FermionField>, par().v);
    auto &w = envGet(std::vector<FermionField>, par().w);

    int nt         = env().getDim().back();
    int N_i        = w.size();
    int N_j        = v.size();
    int ngamma     = gamma_.size();
    int nmom       = mom_.size();
    int block      = par().block;
    int cacheBlock = par().cacheBlock;

    LOG(Message) << "Computing all-to-all meson fields" << std::endl;
    LOG(Message) << "W: '" << par().w << "' V: '" << par().v << "'" << std::endl;
    LOG(Message) << "Meson field size: " << nt << "*" << N_i << "*" << N_j 
                 << " (" << sizeString(nt*N_i*N_j*sizeof(Complex)) << ")" << std::endl;
    LOG(Message) << "Momenta:" << std::endl;
    for (auto &p: mom_)
    {
        LOG(Message) << "  " << p << std::endl;
    }
    LOG(Message) << "Spin structures:" << std::endl;
    for (auto &g: gamma_)
    {
        LOG(Message) << "  " << g << std::endl;
    }

    ///////////////////////////////////////////////
    // Momentum setup
    ///////////////////////////////////////////////
    auto &ph = envGet(std::vector<LatticeComplex>, momphName_);

    if (!hasPhase_)
    {
        startTimer("Momentum phases");
        for (unsigned int j = 0; j < nmom; ++j)
        {
            Complex           i(0.0,1.0);
            std::vector<Real> p;

            envGetTmp(LatticeComplex, coor);
            ph[j] = zero;
            for(unsigned int mu = 0; mu < mom_[j].size(); mu++)
            {
                LatticeCoordinate(coor, mu);
                ph[j] = ph[j] + (mom_[j][mu]/env().getDim(mu))*coor;
            }
            ph[j] = exp((Real)(2*M_PI)*i*ph[j]);
        }
        hasPhase_ = true;
        stopTimer("Momentum phases");
    }
    
    //////////////////////////////////////////////////////////////////////////
    // i,j   is first  loop over SchurBlock factors reusing 5D matrices
    // ii,jj is second loop over cacheBlock factors for high perf contractoin
    // iii,jjj are loops within cacheBlock
    // Total index is sum of these  i+ii+iii etc...
    //////////////////////////////////////////////////////////////////////////
    
    double flops = 0.0;
    double bytes = 0.0;
    double vol   = env().getVolume();
    double t_contr=0;


    envGetTmp(Vector<Complex>, mfBuf);
    envGetTmp(Vector<Complex>, mfCache);
    
    double t0    = usecond();
    int NBlock_i = N_i/block + (((N_i % block) != 0) ? 1 : 0);
    int NBlock_j = N_j/block + (((N_j % block) != 0) ? 1 : 0);

    for(int i=0;i<N_i;i+=block)
    for(int j=0;j<N_j;j+=block)
    {
        // Get the W and V vectors for this block^2 set of terms
        int N_ii = MIN(N_i-i,block);
        int N_jj = MIN(N_j-j,block);

        LOG(Message) << "Meson field block " 
                    << j/block + NBlock_j*i/block + 1 
                    << "/" << NBlock_i*NBlock_j << " [" << i <<" .. " 
                    << i+N_ii-1 << ", " << j <<" .. " << j+N_jj-1 << "]" 
                    << std::endl;

        MesonField mfBlock(mfBuf.data(),nmom,ngamma,nt,N_ii,N_jj);

        // Series of cache blocked chunks of the contractions within this block
        for(int ii=0;ii<N_ii;ii+=cacheBlock)
        for(int jj=0;jj<N_jj;jj+=cacheBlock)
        {
            int N_iii = MIN(N_ii-ii,cacheBlock);
            int N_jjj = MIN(N_jj-jj,cacheBlock);
            MesonField mfCacheBlock(mfCache.data(),nmom,ngamma,nt,N_iii,N_jjj);    

            startTimer("contraction: total");
            makeMesonFieldBlock(mfCacheBlock, &w[i+ii], &v[j+jj], gamma_, ph, 
                                env().getNd() - 1, this);
            stopTimer("contraction: total");
            
            // flops for general N_c & N_s
            flops += vol * ( 2 * 8.0 + 6.0 + 8.0*nmom) * N_iii*N_jjj*ngamma;
            bytes += vol * (12.0 * sizeof(Complex) ) * N_iii*N_jjj
                +  vol * ( 2.0 * sizeof(Complex) *nmom ) * N_iii*N_jjj* ngamma;

            startTimer("cache copy");

            parallel_for_nest5(int iii=0;iii< N_iii;iii++)
            for(int jjj=0;jjj< N_jjj;jjj++)
            for(int m =0;m< nmom;m++)
            for(int g =0;g< ngamma;g++)
            for(int t =0;t< nt;t++)
            {
                mfBlock(m,g,t,ii+iii,jj+jjj) = mfCacheBlock(m,g,t,iii,jjj);
            }
            stopTimer("cache copy");
        }

        // IO
        if (!par().output.empty())
        {
            double       blockSize, ioTime;
            unsigned int myRank = env().getGrid()->ThisRank(),
                         nRank  = env().getGrid()->RankCount();
        
            LOG(Message) << "Writing block to disk" << std::endl;
            ioTime = -getDTimer("IO: write block");
            startTimer("IO: total");
            makeFileDir(filename(0, 0), env().getGrid());
#ifdef MF_PARALLEL_IO
            env().getGrid()->Barrier();
            nodeFile_.clear();
            for(int f = myRank; f < nmom*ngamma; f += nRank)
            {
                std::pair<unsigned int, unsigned int> file;

                file.first  = f/ngamma;
                file.second = f % ngamma;
                nodeFile_.push_back(file);
            }
            // parallel IO
            for (auto &f: nodeFile_)
            {
                auto m = f.first, g = f.second;

                if ((i == 0) and (j == 0))
                {
                    startTimer("IO: file creation");
                    initFile(m, g);
                    stopTimer("IO: file creation");
                }
                startTimer("IO: write block");
                saveBlock(mfBlock, m, g, i, j);
                stopTimer("IO: write block");
            }
            env().getGrid()->Barrier();
#else
            // serial IO
            for(int m = 0; m < nmom; m++)
            for(int g = 0; g < ngamma; g++)
            {   
                if ((i == 0) and (j == 0))
                {
                    startTimer("IO: file creation");
                    if (env().getGrid()->IsBoss())
                    {
                        initFile(m, g);
                    }
                    stopTimer("IO: file creation");
                }
                startTimer("IO: write block");
                if (env().getGrid()->IsBoss())
                {
                    saveBlock(mfBlock, m, g, i, j);
                }
                stopTimer("IO: write block");
            }
#endif
            stopTimer("IO: total");
            blockSize  = static_cast<double>(nmom*ngamma*nt*N_ii*N_jj*sizeof(Complex));
            ioTime    += getDTimer("IO: write block");
            LOG(Message) << "HDF5 IO done " << sizeString(blockSize) << " in "
                         << getTimer("IO: write block")  << " us (" 
                         << blockSize/ioTime*1.0e6/1024/1024
                         << " MB/s)" << std::endl;
        }
    }

    double nodes    = env().getGrid()->NodeCount();
    double t_kernel = getDTimer("contraction: colour trace & mom.")
                      + getDTimer("contraction: local space sum");

    LOG(Message) << "Perf " << flops/t_kernel/1.0e3/nodes << " Gflop/s/node "  << std::endl;
    LOG(Message) << "Perf " << bytes/t_kernel/1.0e3/nodes << " GB/s/node "  << std::endl;
}

// IO
template <typename FImpl>
std::string TA2AMesonField<FImpl>::ioname(unsigned int m, unsigned int g) const
{
    std::stringstream ss;

    ss << gamma_[g] << "_";
    for (unsigned int mu = 0; mu < mom_[m].size(); ++mu)
    {
        ss << mom_[m][mu] << ((mu == mom_[m].size() - 1) ? "" : "_");
    }

    return ss.str();
}

template <typename FImpl>
std::string TA2AMesonField<FImpl>::filename(unsigned int m, unsigned int g) const
{
    return par().output + "." + std::to_string(vm().getTrajectory()) 
           + "/" + ioname(m, g) + ".h5";
}

template <typename FImpl>
void TA2AMesonField<FImpl>::initFile(unsigned int m, unsigned int g)
{
#ifdef HAVE_HDF5
    std::string  f     = filename(m, g);
    auto         &v    = envGet(std::vector<FermionField>, par().v);
    auto         &w    = envGet(std::vector<FermionField>, par().w);
    int          nt    = env().getDim().back();
    int          N_i   = w.size();
    int          N_j   = v.size();

    Hdf5Writer              writer(f);
    std::vector<hsize_t>    dim = {static_cast<hsize_t>(nt), 
                                   static_cast<hsize_t>(N_i), 
                                   static_cast<hsize_t>(N_j)},
                            chunk = {static_cast<hsize_t>(nt), 
                                     static_cast<hsize_t>(par().block), 
                                     static_cast<hsize_t>(par().block)};
    H5NS::DataSpace         dataspace(dim.size(), dim.data());
    H5NS::DataSet           dataset;
    H5NS::DSetCreatPropList plist;
    
    push(writer, ioname(m, g));
    write(writer, "momentum", mom_[m]);
    write(writer, "gamma", gamma_[g]);
    auto &group = writer.getGroup();
    plist.setChunk(chunk.size(), chunk.data());
    dataset = group.createDataSet("mesonField", Hdf5Type<Complex>::type(),
                                  dataspace, plist);
#else
    HADRONS_ERROR(Implementation, "meson field I/O needs HDF5 library");
#endif
}

template <typename FImpl>
void TA2AMesonField<FImpl>::saveBlock(const MesonField &mf,
                                      unsigned int m, unsigned int g, 
                                      unsigned int i, unsigned int j)
{
#ifdef HAVE_HDF5
    std::string          f = filename(m, g);
    Hdf5Reader           reader(f);
    hsize_t              nt = mf.dimension(2),
                            Ni = mf.dimension(3),
                            Nj = mf.dimension(4);
    std::vector<hsize_t> count = {nt, Ni, Nj},
                            offset = {0, static_cast<hsize_t>(i),
                                    static_cast<hsize_t>(j)},
                            stride = {1, 1, 1},
                            block  = {1, 1, 1}; 
    H5NS::DataSpace      memspace(count.size(), count.data()), dataspace;
    H5NS::DataSet        dataset;
    size_t               shift;

    push(reader, ioname(m, g));
    auto &group = reader.getGroup();
    dataset   = group.openDataSet("mesonField");
    dataspace = dataset.getSpace();
    dataspace.selectHyperslab(H5S_SELECT_SET, count.data(), offset.data(),
                                stride.data(), block.data());
    shift = (m*mf.dimension(1) + g)*nt*Ni*Nj;
    dataset.write(mf.data() + shift, Hdf5Type<Complex>::type(), memspace, 
                    dataspace);
#else
    HADRONS_ERROR(Implementation, "meson field I/O needs HDF5 library");
#endif
}

END_MODULE_NAMESPACE

END_HADRONS_NAMESPACE

#endif // Hadrons_MContraction_A2AMesonField_hpp_