idx.h

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/*
 *  GiNaC Copyright (C) 1999-2026 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, see <https://www.gnu.org/licenses/>.
 */
 
#ifndef GINAC_IDX_H
#define GINAC_IDX_H
 
#include "ex.h"
#include "numeric.h"
 
namespace GiNaC {
 
class idx : public basic
{
    GINAC_DECLARE_REGISTERED_CLASS(idx, basic)
 
    // other constructors
public:
    explicit idx(const ex & v, const ex & dim);
 
    // functions overriding virtual functions from base classes
public:
    bool info(unsigned inf) const override;
    size_t nops() const override;
    ex op(size_t i) const override;
    ex map(map_function & f) const override;
    ex evalf() const override;
    ex subs(const exmap & m, unsigned options = 0) const override;
    void archive(archive_node& n) const override;
    void read_archive(const archive_node& n, lst& syms) override;
protected:
    ex derivative(const symbol & s) const override;
    bool match_same_type(const basic & other) const override;
    unsigned calchash() const override;
 
    // new virtual functions in this class
public:
    virtual bool is_dummy_pair_same_type(const basic & other) const;
 
    // non-virtual functions in this class
public:
    ex get_value() const {return value;}
 
    bool is_numeric() const {return is_exactly_a<numeric>(value);}
 
    bool is_symbolic() const {return !is_exactly_a<numeric>(value);}
 
    ex get_dim() const {return dim;}
 
    bool is_dim_numeric() const {return is_exactly_a<numeric>(dim);}
 
    bool is_dim_symbolic() const {return !is_exactly_a<numeric>(dim);}
 
    ex replace_dim(const ex & new_dim) const;
 
    ex minimal_dim(const idx & other) const;
 
protected:
    void print_index(const print_context & c, unsigned level) const;
    void do_print(const print_context & c, unsigned level) const;
    void do_print_csrc(const print_csrc & c, unsigned level) const;
    void do_print_latex(const print_latex & c, unsigned level) const;
    void do_print_tree(const print_tree & c, unsigned level) const;
 
protected:
    ex value; 
    ex dim;   
};
GINAC_DECLARE_UNARCHIVER(idx); 
 
 
class varidx : public idx
{
    GINAC_DECLARE_REGISTERED_CLASS(varidx, idx)
 
    // other constructors
public:
    varidx(const ex & v, const ex & dim, bool covariant = false);
 
    // functions overriding virtual functions from base classes
public:
    bool is_dummy_pair_same_type(const basic & other) const override;
    void archive(archive_node& n) const override;
    void read_archive(const archive_node& n, lst& syms) override;
protected:
    bool match_same_type(const basic & other) const override;
 
    // non-virtual functions in this class
public:
    bool is_covariant() const {return covariant;}
 
    bool is_contravariant() const {return !covariant;}
 
    ex toggle_variance() const;
 
protected:
    void do_print(const print_context & c, unsigned level) const;
    void do_print_tree(const print_tree & c, unsigned level) const;
 
    // member variables
protected:
    bool covariant; 
};
GINAC_DECLARE_UNARCHIVER(varidx);
 
 
class spinidx : public varidx
{
    GINAC_DECLARE_REGISTERED_CLASS(spinidx, varidx)
 
    // other constructors
public:
    spinidx(const ex & v, const ex & dim = 2, bool covariant = false, bool dotted = false);
 
    // functions overriding virtual functions from base classes
public:
    bool is_dummy_pair_same_type(const basic & other) const override;
    // complex conjugation
    ex conjugate() const override { return toggle_dot(); }
    void archive(archive_node& n) const override;
    void read_archive(const archive_node& n, lst& syms) override;
protected:
    bool match_same_type(const basic & other) const override;
 
    // non-virtual functions in this class
public:
    bool is_dotted() const {return dotted;}
 
    bool is_undotted() const {return !dotted;}
 
    ex toggle_dot() const;
 
    ex toggle_variance_dot() const;
 
protected:
    void do_print(const print_context & c, unsigned level) const;
    void do_print_latex(const print_latex & c, unsigned level) const;
    void do_print_tree(const print_tree & c, unsigned level) const;
 
    // member variables
protected:
    bool dotted;
};
GINAC_DECLARE_UNARCHIVER(spinidx);
 
 
// utility functions
 
bool is_dummy_pair(const idx & i1, const idx & i2);
 
bool is_dummy_pair(const ex & e1, const ex & e2);
 
void find_free_and_dummy(exvector::const_iterator it, exvector::const_iterator itend, exvector & out_free, exvector & out_dummy);
 
inline void find_free_and_dummy(const exvector & v, exvector & out_free, exvector & out_dummy)
{
    find_free_and_dummy(v.begin(), v.end(), out_free, out_dummy);
}
 
inline void find_dummy_indices(const exvector & v, exvector & out_dummy)
{
    exvector free_indices;
    find_free_and_dummy(v.begin(), v.end(), free_indices, out_dummy);
}
 
inline size_t count_dummy_indices(const exvector & v)
{
    exvector free_indices, dummy_indices;
    find_free_and_dummy(v.begin(), v.end(), free_indices, dummy_indices);
    return dummy_indices.size();
}
 
inline size_t count_free_indices(const exvector & v)
{
    exvector free_indices, dummy_indices;
    find_free_and_dummy(v.begin(), v.end(), free_indices, dummy_indices);
    return free_indices.size();
}
 
ex minimal_dim(const ex & dim1, const ex & dim2);
 
} // namespace GiNaC
 
#endif // ndef GINAC_IDX_H