mpi_utils.h

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#ifndef MPI_UTILS_H
#define MPI_UTILS_H

#ifdef PARALLEL
#include <mpi.h>
#endif
#include <string>
#include <vector>
#include <assert.h>
#include "util.h"

#ifdef PARALLEL
template<typename T> MPI_Datatype MPI_getType();
template<> inline MPI_Datatype MPI_getType<bool>()          {
    switch(sizeof(bool)) {
    case 1: return MPI_CHAR;
    case 2: return MPI_SHORT;
    case 4: return MPI_INT;
    case 8: return MPI_LONG;
    default: assert(sizeof(bool)==1);
    }
}

template<> inline MPI_Datatype MPI_getType<char>()          {return MPI_CHAR;}
template<> inline MPI_Datatype MPI_getType<unsigned char>() {return MPI_BYTE;}
template<> inline MPI_Datatype MPI_getType<short>()         {return MPI_SHORT;}
template<> inline MPI_Datatype MPI_getType<unsigned short>(){return MPI_UNSIGNED_SHORT;}
template<> inline MPI_Datatype MPI_getType<int>()           {return MPI_INT;}
template<> inline MPI_Datatype MPI_getType<unsigned int>()  {return MPI_UNSIGNED;}
template<> inline MPI_Datatype MPI_getType<long>()          {return MPI_LONG;}
template<> inline MPI_Datatype MPI_getType<unsigned long>() {return MPI_UNSIGNED_LONG;}
template<> inline MPI_Datatype MPI_getType<unsigned long long>() {return MPI_UNSIGNED_LONG;}
template<> inline MPI_Datatype MPI_getType<float>()         {return MPI_FLOAT;}
template<> inline MPI_Datatype MPI_getType<double>()        {return MPI_DOUBLE;}
#endif

int mpi_bcast_vector_of_strings(vector<string> &vector_of_strings) ;         
int mpi_bcast_string(std::string &ss);

template<typename T> int mpi_bcast_scalar(T &elem) {
        #ifdef PARALLEL
                MPI_Bcast( &elem, 1, MPI_getType<T>(), 0, MPI_COMM_WORLD );
        #endif
        return 0;
}

template<class T>  int mpi_bcast_vector( std::vector<T> &v) {
    typename std::vector<T>::iterator it;
    int proc_id=0,nump=1;
    util::get_proc_id_nump(proc_id,nump);   
    unsigned int sz;

    if (proc_id==0)
        sz = v.size();

    mpi_bcast_scalar(sz);

    if (proc_id!=0)
        v.resize(sz);
    for( it=v.begin(); it!=v.end(); it++ )
        mpi_bcast_scalar(*it);
    return 0;
}

template<class T> int mpi_bcast_matrix( std::vector< std::vector<T> > &m) {


    int proc_id=0,nump=1;
    util::get_proc_id_nump(proc_id,nump);   
    int rows, cols;     
    if (proc_id==0) {
        rows=m.size(); cols=m[0].size();
    }
    mpi_bcast_scalar(rows);
    mpi_bcast_scalar(cols);
    if (proc_id!=0) 
        m.resize(rows,vector<T>(cols));
    for (int i=0;i<rows;i++)
        mpi_bcast_vector(m[i]);
        
}

#endif