This class holds one index of an indexed object. More...

#include <idx.h>

Inheritance diagram for GiNaC::idx:

Public Member Functions
	idx (const ex &v, const ex &dim)
	Construct index with given value and dimension.
bool	info (unsigned inf) const
	Information about the object.
size_t	nops () const
	Number of operands/members.
ex	op (size_t i) const
	Return operand/member at position i.
ex	map (map_function &f) const
	Construct new expression by applying the specified function to all sub-expressions (one level only, not recursively).
ex	evalf (int level=0) const
	By default, basic::evalf would evaluate the index value but we don't want a.1 to become a.
ex	subs (const exmap &m, unsigned options=0) const
	Substitute a set of objects by arbitrary expressions.
void	archive (archive_node &n) const
	Save (serialize) the object into archive node.
void	read_archive (const archive_node &n, lst &syms)
	Load (deserialize) the object from an archive node.
virtual bool	is_dummy_pair_same_type (const basic &other) const
	Check whether the index forms a dummy index pair with another index of the same type.
ex	get_value () const
	Get value of index.
bool	is_numeric () const
	Check whether the index is numeric.
bool	is_symbolic () const
	Check whether the index is symbolic.
ex	get_dim () const
	Get dimension of index space.
bool	is_dim_numeric () const
	Check whether the dimension is numeric.
bool	is_dim_symbolic () const
	Check whether the dimension is symbolic.
ex	replace_dim (const ex &new_dim) const
	Make a new index with the same value but a different dimension.
ex	minimal_dim (const idx &other) const
	Return the minimum of the dimensions of this and another index.
Protected Member Functions
ex	derivative (const symbol &s) const
	Implementation of ex::diff() for an index always returns 0.
bool	match_same_type (const basic &other) const
	Returns true if the attributes of two objects are similar enough for a match.
unsigned	calchash () const
	Compute the hash value of an object and if it makes sense to store it in the objects status_flags, do so.
void	print_index (const print_context &c, unsigned level) const
void	do_print (const print_context &c, unsigned level) const
	Default output to stream.
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
	Tree output to stream.
Protected Attributes
ex	value
	Expression that constitutes the index (numeric or symbolic name)
ex	dim
	Dimension of space (can be symbolic or numeric)

Detailed Description

This class holds one index of an indexed object.

Indices can theoretically consist of any symbolic expression but they are usually only just a symbol (e.g. "mu", "i") or numeric (integer). Indices belong to a space with a certain numeric or symbolic dimension.

Definition at line 35 of file idx.h.

Constructor & Destructor Documentation

GiNaC::idx::idx	(	const ex &	v,
		const ex &	dim
	)		`[explicit]`

Construct index with given value and dimension.

Parameters:

v	Value of index (numeric or symbolic)
dim	Dimension of index space (numeric or symbolic)

Returns:: newly constructed index

Definition at line 72 of file idx.cpp.

References dim, GiNaC::ex::info(), is_dim_numeric(), and GiNaC::info_flags::posint.

Member Function Documentation

bool GiNaC::idx::info ( unsigned inf ) const [virtual]

Information about the object.

See also:: class info_flags

Reimplemented from GiNaC::basic.

Definition at line 234 of file idx.cpp.

References GiNaC::info_flags::has_indices, and GiNaC::info_flags::idx.

size_t GiNaC::idx::nops ( ) const [virtual]

Number of operands/members.

Reimplemented from GiNaC::basic.

Definition at line 244 of file idx.cpp.

ex GiNaC::idx::op ( size_t i ) const [virtual]

Return operand/member at position i.

Reimplemented from GiNaC::basic.

Definition at line 250 of file idx.cpp.

References GINAC_ASSERT, and value.

ex GiNaC::idx::map ( map_function & f ) const [virtual]

Construct new expression by applying the specified function to all sub-expressions (one level only, not recursively).

Reimplemented from GiNaC::basic.

Definition at line 256 of file idx.cpp.

References GiNaC::are_ex_trivially_equal(), GiNaC::basic::clearflag(), GiNaC::basic::duplicate(), GiNaC::status_flags::dynallocated, GiNaC::status_flags::hash_calculated, GiNaC::basic::setflag(), and value.

ex GiNaC::idx::evalf ( int level = 0 ) const [virtual]

By default, basic::evalf would evaluate the index value but we don't want a.1 to become a.

(1.0).

Reimplemented from GiNaC::basic.

Definition at line 369 of file idx.cpp.

ex GiNaC::idx::subs	(	const exmap &	m,
		unsigned	options = `0`
	)		const `[virtual]`

Substitute a set of objects by arbitrary expressions.

The ex returned will already be evaluated.

Reimplemented from GiNaC::basic.

Definition at line 374 of file idx.cpp.

References GiNaC::are_ex_trivially_equal(), GiNaC::basic::clearflag(), GiNaC::basic::duplicate(), GiNaC::status_flags::dynallocated, GiNaC::ex::find(), GiNaC::status_flags::hash_calculated, GiNaC::subs_options::really_subs_idx, GiNaC::basic::setflag(), GiNaC::ex::subs(), and value.

Referenced by GiNaC::spinmetric::contract_with().

void GiNaC::idx::archive ( archive_node & n ) const [virtual]

Save (serialize) the object into archive node.

Archive the object.

Losely speaking, this method turns an expression into a byte stream (which can be saved and restored later on, or sent via network, etc.)

Reimplemented from GiNaC::basic.

Reimplemented in GiNaC::spinidx, and GiNaC::varidx.

Definition at line 113 of file idx.cpp.

References GiNaC::archive_node::add_ex(), dim, and value.

void GiNaC::idx::read_archive	(	const archive_node &	n,
		lst &	syms
	)		`[virtual]`

Load (deserialize) the object from an archive node.

Construct object from archive_node.

Note:: This method is essentially a constructor. However, constructors can't be virtual. So, if unarchiving routines are implemented as constructors one would need to define such a constructor in every class, even if all it does is simply calling constructor of a superclass.

Reimplemented from GiNaC::basic.

Reimplemented in GiNaC::spinidx, and GiNaC::varidx.

Definition at line 91 of file idx.cpp.

References dim, GiNaC::archive_node::find_ex(), and value.

ex GiNaC::idx::derivative ( const symbol & s ) const [protected, virtual]

Implementation of ex::diff() for an index always returns 0.

See also:: ex::diff

Reimplemented from GiNaC::basic.

Definition at line 405 of file idx.cpp.

References GiNaC::_ex0.

bool GiNaC::idx::match_same_type ( const basic & other ) const [protected, virtual]

Returns true if the attributes of two objects are similar enough for a match.

This function must not match subexpressions (this is already done by basic::match()). Only attributes not accessible by op() should be compared. This is also the reason why this function doesn't take the wildcard replacement list from match() as an argument: only subexpressions are subject to wildcard matches. Also, this function only needs to be implemented for container classes because is_equal_same_type() is automatically used instead of match_same_type() if nops() == 0.

See also:: basic::match

Reimplemented from GiNaC::basic.

Reimplemented in GiNaC::spinidx, and GiNaC::varidx.

Definition at line 283 of file idx.cpp.

References dim, GINAC_ASSERT, and GiNaC::ex::is_equal().

unsigned GiNaC::idx::calchash ( ) const [protected, virtual]

Compute the hash value of an object and if it makes sense to store it in the objects status_flags, do so.

The method inherited from class basic computes a hash value based on the type and hash values of possible members. For this reason it is well suited for container classes but atomic classes should override this implementation because otherwise they would all end up with the same hashvalue.

Reimplemented from GiNaC::basic.

Definition at line 344 of file idx.cpp.

References GiNaC::status_flags::evaluated, GiNaC::basic::flags, GiNaC::ex::gethash(), GiNaC::status_flags::hash_calculated, GiNaC::basic::hashvalue, GiNaC::make_hash_seed(), GiNaC::rotate_left(), GiNaC::basic::setflag(), and value.