PermLib

symmetric_group.h

00001 // ---------------------------------------------------------------------------
00002 //
00003 //  This file is part of PermLib.
00004 //
00005 // Copyright (c) 2009-2011 Thomas Rehn <thomas@carmen76.de>
00006 // All rights reserved.
00007 // 
00008 // Redistribution and use in source and binary forms, with or without
00009 // modification, are permitted provided that the following conditions
00010 // are met:
00011 // 1. Redistributions of source code must retain the above copyright
00012 //    notice, this list of conditions and the following disclaimer.
00013 // 2. Redistributions in binary form must reproduce the above copyright
00014 //    notice, this list of conditions and the following disclaimer in the
00015 //    documentation and/or other materials provided with the distribution.
00016 // 3. The name of the author may not be used to endorse or promote products
00017 //    derived from this software without specific prior written permission.
00018 // 
00019 // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
00020 // IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
00021 // OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
00022 // IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
00023 // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
00024 // NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
00025 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
00026 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
00027 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
00028 // THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00029 //
00030 // ---------------------------------------------------------------------------
00031 
00032 
00033 #ifndef SYMMETRICGROUP_H_
00034 #define SYMMETRICGROUP_H_
00035 
00036 #include <permlib/bsgs_core.h>
00037 #include <permlib/transversal/symmetric_group_transversal.h>
00038 
00039 #include <boost/shared_ptr.hpp>
00040 
00041 namespace permlib {
00042 
00044 
00051 template<class PERM>
00052 struct SymmetricGroup : public BSGSCore<PERM, SymmetricGroupTransversal<PERM> > {
00054         explicit SymmetricGroup(unsigned int n);
00056         SymmetricGroup(const SymmetricGroup<PERM>& symGroup);
00058         SymmetricGroup& operator=(const SymmetricGroup<PERM>& symGroup);
00059         
00061         typedef SymmetricGroupTransversal<PERM> TRANS;
00062         
00063         virtual bool isSymmetricGroup() const { return true; }
00064 private:
00065         void copy(const SymmetricGroup<PERM>& symGroup);
00066 };
00067 
00068 template<class PERM>
00069 inline SymmetricGroup<PERM>::SymmetricGroup(unsigned int n)
00070         : BSGSCore<PERM,TRANS>(-n, n, n)
00071 {
00072         BSGSCore<PERM,TRANS>::U.reserve(n);
00073         for (unsigned int i = 0; i < n; ++i) {
00074                 BSGSCore<PERM,TRANS>::B[i] = n-1-i;
00075                 BSGSCore<PERM,TRANS>::U.push_back(SymmetricGroupTransversal<PERM>(this, i));
00076                 if (i < n-1) {
00077                         boost::shared_ptr<PERM> gen(new PERM(n));
00078                         gen->setTransposition(i, i+1);
00079                         BSGSCore<PERM,TRANS>::S.push_back(gen);
00080                 }
00081         }
00082 }
00083 
00084 template<class PERM>
00085 inline void SymmetricGroup<PERM>::copy(const SymmetricGroup<PERM>& symGroup) 
00086 {
00087         const unsigned long& n = symGroup.n;
00088         BSGSCore<PERM,TRANS>::U.reserve(n);
00089         for (unsigned int i = 0; i < n; ++i) {
00090                 BSGSCore<PERM,TRANS>::B[i] = symGroup.B[i];
00091                 BSGSCore<PERM,TRANS>::U.push_back(SymmetricGroupTransversal<PERM>(this, i));
00092                 if (i < n-1) {
00093                         boost::shared_ptr<PERM> gen(new PERM(n));
00094                         gen->setTransposition(i, i+1);
00095                         BSGSCore<PERM,TRANS>::S.push_back(gen);
00096                 }
00097         }
00098 }
00099 
00100 template<class PERM>
00101 inline SymmetricGroup<PERM>::SymmetricGroup(const SymmetricGroup<PERM>& symGroup) 
00102         : BSGSCore<PERM,TRANS>(-symGroup.n, symGroup.n, symGroup.n)
00103 {
00104         copy(symGroup);
00105 }
00106 
00107 template<class PERM>
00108 inline SymmetricGroup<PERM>& SymmetricGroup<PERM>::operator=(const SymmetricGroup<PERM>& symGroup) 
00109 {
00110         BOOST_ASSERT(symGroup.n == this->n);
00111         
00112         BSGSCore<PERM,TRANS>::n = symGroup.n;
00113         BSGSCore<PERM,TRANS>::m_id = symGroup.m_id;
00114         copy(symGroup);
00115         return *this;
00116 }
00117 
00118 }
00119 
00120 
00121 #endif // SYMMETRICGROUP_H_