tensor.h

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/*
 *  GiNaC Copyright (C) 1999-2011 Johannes Gutenberg University Mainz, Germany
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef GINAC_TENSOR_H
#define GINAC_TENSOR_H

#include "ex.h"
#include "archive.h"

namespace GiNaC {

class tensor : public basic
{
    GINAC_DECLARE_REGISTERED_CLASS(tensor, basic)

    // functions overriding virtual functions from base classes
protected:
    unsigned return_type() const { return return_types::noncommutative_composite; }

    // non-virtual functions in this class
public:
    bool replace_contr_index(exvector::iterator self, exvector::iterator other) const;
};


class tensdelta : public tensor
{
    GINAC_DECLARE_REGISTERED_CLASS(tensdelta, tensor)

    // functions overriding virtual functions from base classes
public:
    bool info(unsigned inf) const;
    ex eval_indexed(const basic & i) const;
    bool contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const;

    // non-virtual functions in this class
protected:
    unsigned return_type() const { return return_types::commutative; }
    void do_print(const print_context & c, unsigned level) const;
    void do_print_latex(const print_latex & c, unsigned level) const;
};
GINAC_DECLARE_UNARCHIVER(tensdelta);


class tensmetric : public tensor
{
    GINAC_DECLARE_REGISTERED_CLASS(tensmetric, tensor)

    // functions overriding virtual functions from base classes
public:
    bool info(unsigned inf) const;
    ex eval_indexed(const basic & i) const;
    bool contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const;

    // non-virtual functions in this class
protected:
    unsigned return_type() const { return return_types::commutative; }
    void do_print(const print_context & c, unsigned level) const;
};
GINAC_DECLARE_UNARCHIVER(tensmetric);


class minkmetric : public tensmetric
{
    GINAC_DECLARE_REGISTERED_CLASS(minkmetric, tensmetric)

    // other constructors
public:
    minkmetric(bool pos_sig);

    // functions overriding virtual functions from base classes
public:
    bool info(unsigned inf) const;
    ex eval_indexed(const basic & i) const;

    void archive(archive_node& n) const;
    void read_archive(const archive_node& n, lst& syms);
    // non-virtual functions in this class
protected:
    unsigned return_type() const { return return_types::commutative; }
    void do_print(const print_context & c, unsigned level) const;
    void do_print_latex(const print_latex & c, unsigned level) const;

    // member variables
private:
    bool pos_sig; 
};
GINAC_DECLARE_UNARCHIVER(minkmetric); 


class spinmetric : public tensmetric
{
    GINAC_DECLARE_REGISTERED_CLASS(spinmetric, tensmetric)

    // functions overriding virtual functions from base classes
public:
    bool info(unsigned inf) const;
    ex eval_indexed(const basic & i) const;
    bool contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const;

protected:
    void do_print(const print_context & c, unsigned level) const;
    void do_print_latex(const print_latex & c, unsigned level) const;
};
GINAC_DECLARE_UNARCHIVER(spinmetric);


class tensepsilon : public tensor
{
    GINAC_DECLARE_REGISTERED_CLASS(tensepsilon, tensor)

    // other constructors
public:
    tensepsilon(bool minkowski, bool pos_sig);

    // functions overriding virtual functions from base classes
public:
    bool info(unsigned inf) const;
    ex eval_indexed(const basic & i) const;
    bool contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const;

    void archive(archive_node& n) const;
    void read_archive(const archive_node& n, lst& syms);
    // non-virtual functions in this class
protected:
    unsigned return_type() const { return return_types::commutative; }
    void do_print(const print_context & c, unsigned level) const;
    void do_print_latex(const print_latex & c, unsigned level) const;

    // member variables
private:
    bool minkowski; 
    bool pos_sig;   
};
GINAC_DECLARE_UNARCHIVER(tensepsilon); 


// utility functions

ex delta_tensor(const ex & i1, const ex & i2);

ex metric_tensor(const ex & i1, const ex & i2);

ex lorentz_g(const ex & i1, const ex & i2, bool pos_sig = false);

ex spinor_metric(const ex & i1, const ex & i2);

ex epsilon_tensor(const ex & i1, const ex & i2);

ex epsilon_tensor(const ex & i1, const ex & i2, const ex & i3);

ex lorentz_eps(const ex & i1, const ex & i2, const ex & i3, const ex & i4, bool pos_sig = false);

} // namespace GiNaC

#endif // ndef GINAC_TENSOR_H