ring.cpp

/*****************************************************************************
 *   Copyright (C) 2004-2015 The PaGMO development team,                     *
 *   Advanced Concepts Team (ACT), European Space Agency (ESA)               *
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 *   https://github.com/esa/pagmo                                            *
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 *   act@esa.int                                                             *
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#include <string>

#include "../exceptions.h"
#include "base.h"
#include "ring.h"

namespace pagmo { namespace topology {

ring::ring():base(),m_first(0),m_last(0) {}

base_ptr ring::clone() const
{
        return base_ptr(new ring(*this));
}

void ring::connect(const vertices_size_type &n)
{
        // Store frequently-used variables.
        const vertices_size_type t_size = get_number_of_vertices();
        pagmo_assert(t_size != 0);
        switch (t_size) {
        case 1: {
                        // If the topology was empty, just update the id of the first element.
                        m_first = n;
                        break;
                }
        case 2: {
                        pagmo_assert(n != m_first);
                        // Add connections to the only existing element.
                        add_edge(m_first,n);
                        add_edge(n,m_first);
                        break;
                }
        case 3: {
                        // Add new connections.
                        add_edge(m_last,n);
                        add_edge(n,m_last);
                        add_edge(m_first,n);
                        add_edge(n,m_first);
                        break;
                }
        default: {
                        // In general we must change the back connection of the first,
                        // the forward connection of the current last, and add the new last
                        // with proper connections.
                        remove_edge(m_last,m_first);
                        remove_edge(m_first,m_last);
                        add_edge(m_last,n);
                        add_edge(n,m_last);
                        add_edge(m_first,n);
                        add_edge(n,m_first);
                }
        }
        // Update the id of the last island.
        m_last = n;
}

std::string ring::get_name() const
{
        return "Ring";
}

}} //namespaces

BOOST_CLASS_EXPORT_IMPLEMENT(pagmo::topology::ring)