RandomFixNumberConnections.cpp

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#include "RandomFixNumberConnections.h"

RandomFixNumberConnections::RandomFixNumberConnections(const double conn_prob)
    : conn_prob(conn_prob)
{
    if (conn_prob <= 0 || conn_prob > 1)
        throw PCSIM::Exception( "RandomConnections::RandomConnections" , "Connection probability must lie in interval (0,1]" );

    if (conn_prob != 1)
        uni_rnd = new UniformDistribution(0.0, 1.0);
}


RandomFixNumberConnections::RandomFixNumberConnections(const double conn_prob, MPI::Intracomm const&)
    : conn_prob(conn_prob)
{
    if (conn_prob <= 0 || conn_prob > 1)
        throw PCSIM::Exception( "RandomConnections::RandomConnections" , "Connection probability must lie in interval (0,1]" );

    if (conn_prob != 1)
        uni_rnd = new UniformDistribution(0.0, 1.0);

    num_connections=0;
}


RandomFixNumberConnections::~RandomFixNumberConnections()
{
    if (conn_prob != 1)
        delete uni_rnd;

    num_connections=0;
}


void RandomFixNumberConnections::init(const SimObjectPopulation &srcPopulation, const SimObjectPopulation &destPopulation)
{
    src_popul =  &srcPopulation;
    dest_popul = &destPopulation;

    num_connections = (unsigned int)round(conn_prob*srcPopulation.size() * destPopulation.size()); 
}


size_t RandomFixNumberConnections::estimate()
{
    return num_connections;
}


void RandomFixNumberConnections::reset(SimObject::ID::SortedVector::const_iterator src_begin_it,
        SimObject::ID::SortedVector::const_iterator src_end_it,
        SimObject::ID::SortedVector::const_iterator dest_begin_it,
        SimObject::ID::SortedVector::const_iterator dest_end_it)
{
    curr_src_idx = 0;
    curr_dest_idx = -1;

    from_begin_it = src_begin_it;
    to_begin_it = dest_begin_it;
    src_max_idx = src_end_it - src_begin_it;
    dest_max_idx = dest_end_it - dest_begin_it;

    num_connections = (unsigned int)round(conn_prob * src_max_idx * dest_max_idx); 
}


bool RandomFixNumberConnections:: next( pair<SimObject::ID, SimObject::ID> &conn_pair )
{
    last_conn_valid = false;

    size_t step;
    if (conn_prob == 1)
    {
        step = 1;
        do
        {
            curr_dest_idx += step;
            if (curr_dest_idx >= dest_max_idx) {
                curr_src_idx += size_t(curr_dest_idx / dest_max_idx );
                curr_dest_idx %= dest_max_idx;
            }
            if (curr_src_idx < src_max_idx)
            {
                last_conn_idx.first = *(from_begin_it + curr_src_idx);
                conn_pair.first = (*src_popul).getID(last_conn_idx.first);

                last_conn_idx.second = *(to_begin_it + curr_dest_idx);
                conn_pair.second = (*dest_popul).getID(last_conn_idx.second);
            }
            else
                return false;
        }
        while(conn_pair.first == conn_pair.second);
    }
    else if (connected_pairs.size() < num_connections)
    {
        bool found = false;
        int pre  = 0;
        int post = 0;

        do {
            do {
                pre  = (int)floor(src_max_idx * (*uni_rnd)(*m_rnd_eng));
                post = (int)floor(dest_max_idx *(*uni_rnd)(*m_rnd_eng));
            }
            while (pre==post);

            pair<int, int> pre_post(pre,post);

            if(connected_pairs.find(pre_post) == connected_pairs.end()) {
               connected_pairs.insert(pre_post);
               found = true;
            }
        }
        while(!found);

        last_conn_idx.first = *(from_begin_it + pre);
        conn_pair.first = (*src_popul).getID(last_conn_idx.first);
        last_conn_idx.second = *(to_begin_it + post);
        conn_pair.second = (*dest_popul).getID(last_conn_idx.second);
    }
    else
        return false;

    last_conn_valid = true;

    return true;
}

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