SkewMultiplication Class Reference

Sign-rule helper used by every ring that has a skew-commutative subset of variables (exterior factor, full skew ring, ...). More...

#include <skew.hpp>

Public Member Functions
	SkewMultiplication ()
	SkewMultiplication (int nvars, int nskew, int *skew_list)
	~SkewMultiplication ()
int	n_skew_vars () const
bool	is_skew_var (int i) const
int	skew_variable (int i) const
int	skew_degree (const int *exp) const
int	skew_vars (const int *exp, int *result) const
int	skew_vars (const long *exp, int *result) const
int	mult_sign (const int *exp1, const int *exp2) const
int	mult_sign (const long *exp1, const long *exp2) const
int	diff (const int *exp1, const int *exp2, int *result) const
int	divide (const int *exp1, const int *exp2, int *result) const
bool	exp_is_zero (const int *exp) const

Public Attributes
int	_n_vars
int	_n_skew
int *	_skew_list
bool *	_skew_exp
unsigned long	skew_byte_size

Detailed Description

Sign-rule helper used by every ring that has a skew-commutative subset of variables (exterior factor, full skew ring, ...).

Note

AI-generated documentation. Verify against the source before relying on it.

Stores which of the _n_vars variables are skew (_skew_list[0.._n_skew-1], with _skew_exp[i] a fast "is variable `i` skew?" lookup), plus the byte size used to cache exponent vectors. Hands out the inversion count needed by the wrapping ring's mult_by_term1 to decide the sign of a product, and detects x_i^2 = 0 collapses on the skew side. Full polynomial multiplication still lives in the rings that embed this helper (SkewPolynomialRing, PolyRing with skew factors, F4 / resolution code).

Definition at line 53 of file skew.hpp.

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The documentation for this class was generated from the following files:

• Macaulay2/e/skew.hpp
• Macaulay2/e/skew.cpp