cyclic_group_construction.h

// ---------------------------------------------------------------------------
//
//  This file is part of PermLib.
//
// Copyright (c) 2009-2011 Thomas Rehn <thomas@carmen76.de>
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
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// ---------------------------------------------------------------------------
 
 
#ifndef CYCLIC_GROUP_CONSTRUCTION_H_
#define CYCLIC_GROUP_CONSTRUCTION_H_
 
#include <permlib/construct/known_bsgs_construction.h>
 
namespace permlib {

template <class TRANS>
class CyclicGroupConstruction : public KnownBSGSConstruction<typename TRANS::PERMtype, TRANS> {
public:

        CyclicGroupConstruction(unsigned int n);

        BSGS<typename TRANS::PERMtype, TRANS> construct() const;
};
 
//
//     ----       IMPLEMENTATION
//
 
template <class TRANS>
CyclicGroupConstruction<TRANS>::CyclicGroupConstruction(unsigned int n) 
        : KnownBSGSConstruction<typename TRANS::PERMtype, TRANS>(n)
{ }
 
 
template <class TRANS>
BSGS<typename TRANS::PERMtype, TRANS> CyclicGroupConstruction<TRANS>
        ::construct() const
{
        typedef typename TRANS::PERMtype PERM;
        const unsigned int &n = this->m_n;
        typename PERM::perm genPerm(n);
        for (unsigned int i = 0; i < n; ++i)
                genPerm[i] = (i + 1) % n;
        std::list<typename PERM::ptr> cyclicGenerators;
        cyclicGenerators.push_back(typename PERM::ptr(new PERM(genPerm)));
        const dom_int knownBase[1] = { 0 };
        
        return KnownBSGSConstruction<PERM, TRANS>::construct(cyclicGenerators.begin(), cyclicGenerators.end(), knownBase, knownBase + 1);
}
 
}
 
#endif // -- KNOWNBSGSCONSTRUCTION_H_