distributed_array() [3/3]

template<typename T >

cntr::distributed_array< T >::distributed_array	(	int	n,
		int	maxlen,
		bool	mpi
	)

Initializes the distributed_array class.

Purpose

Initializes the distributed_array class, where template T is a type of the basic unit of data, with or without the MPI support.

Parameters

n	Number of blocks
maxlen	Maximum size of block
mpi	If 'true' use MPI, otherwise one task with tid_=0

Definition at line 88 of file cntr_distributed_array_impl.hpp.

                                                                                        {
    assert(0<=maxlen && 0<=n);
    size_t len;
    maxlen_=maxlen;
    blocksize_ = maxlen_;
    n_=n;
    tid_map_.resize(n_);
    len=maxlen_*n_;
    if(len==0){
        data_=0;
    }else{ 
        data_ = new T [len];
        memset(data_, 0, sizeof(T)*len);
    }
    
    if(mpi){
        #if CNTR_USE_MPI==1
            MPI_Comm_size(MPI_COMM_WORLD, &ntasks_);
            MPI_Comm_rank(MPI_COMM_WORLD, &tid_);
        #else
            tid_=0;
            ntasks_=1;      
        #endif  
    }else{
        tid_=0;
        ntasks_=1;      
    }
    {
        // This distribution tries to spread evenly number of tasks
        int nr_alloced = 0;
        int remainer,buckets;
        for(int i=0;i<ntasks_;i++){
            remainer = n - nr_alloced;
            buckets = (ntasks_ - i);
            int size=remainer/ buckets;
            for(int k=0;k<size;k++){
                tid_map_[nr_alloced+k]=i;
            }
            nr_alloced +=size; //Ceiling division
        }


        // int rank_totblock=0,rank_firstblock=0;
        // // Set position of first block on a given rank
        // for(int i=0;i<n_;i++){
        //  if(tid_map_[i]==tid_){
        //      rank_firstblock=i;
        //      break;
        //  }
        // }
        // // Set number of all blocks on a given rank
        // for(int i=0;i<n_;i++){
        //  if(tid_map_[i]==tid_){
        //      rank_totblock+=1;
        //  }
        // }

        // for(int i=0;i<n_;i++){
        //  std::cout << "Tid map " << tid_ << " " << i << " " << tid_map_[i] << " " <<  rank_totblock << " " << rank_firstblock << std::endl;  
        // }

        // std::cout << " -------------------------------------- " << std::endl;

    }
}