# fmpz_mod_mpoly_factor.h – factorisation of multivariate polynomials over the integers mod n¶

## Types, macros and constants¶

type fmpz_mod_mpoly_factor_struct

A struct for holding a factored polynomial over the integers mod n. There is a single constant and a product of bases to corresponding exponents.

type fmpz_mod_mpoly_factor_t

An array of length $$1$$ of fmpz_mod_mpoly_factor_struct.

## Memory management¶

void fmpz_mod_mpoly_factor_init(fmpz_mod_mpoly_factor_t f, const fmpz_mod_mpoly_ctx_t ctx)

Initialise f.

void fmpz_mod_mpoly_factor_clear(fmpz_mod_mpoly_factor_t f, const fmpz_mod_mpoly_ctx_t ctx)

Clear f.

## Basic manipulation¶

void fmpz_mod_mpoly_factor_swap(fmpz_mod_mpoly_factor_t f, fmpz_mod_mpoly_factor_t g, const fmpz_mod_mpoly_ctx_t ctx)

Efficiently swap f and g.

slong fmpz_mod_mpoly_factor_length(const fmpz_mod_mpoly_factor_t f, const fmpz_mod_mpoly_ctx_t ctx)

Return the length of the product in f.

void fmpz_mod_mpoly_factor_get_constant_fmpz(fmpz_t c, const fmpz_mod_mpoly_factor_t f, const fmpz_mod_mpoly_ctx_t ctx)

Set c to the constant of f.

void fmpz_mod_mpoly_factor_get_base(fmpz_mod_mpoly_t B, const fmpz_mod_mpoly_factor_t f, slong i, const fmpz_mod_mpoly_ctx_t ctx)
void fmpz_mod_mpoly_factor_swap_base(fmpz_mod_mpoly_t B, fmpz_mod_mpoly_factor_t f, slong i, const fmpz_mod_mpoly_ctx_t ctx)

Set (resp. swap) B to (resp. with) the base of the term of index i in f.

slong fmpz_mod_mpoly_factor_get_exp_si(fmpz_mod_mpoly_factor_t f, slong i, const fmpz_mod_mpoly_ctx_t ctx)

Return the exponent of the term of index i in f. It is assumed to fit an slong.

void fmpz_mod_mpoly_factor_sort(fmpz_mod_mpoly_factor_t f, const fmpz_mod_mpoly_ctx_t ctx)

Sort the product of f first by exponent and then by base.

## Factorisation¶

A return of $$1$$ indicates that the function was successful. Otherwise, the return is $$0$$ and f is undefined. None of these functions multiply f by A: f is simply set to a factorisation of A, and thus these functions should not depend on the initial value of the output f.

int fmpz_mod_mpoly_factor_squarefree(fmpz_mod_mpoly_factor_t f, const fmpz_mod_mpoly_t A, const fmpz_mod_mpoly_ctx_t ctx)

Set f to a factorization of A where the bases are primitive and pairwise relatively prime. If the product of all irreducible factors with a given exponent is desired, it is recommended to call fmpz_mod_mpoly_factor_sort() and then multiply the bases with the desired exponent.

int fmpz_mod_mpoly_factor(fmpz_mod_mpoly_factor_t f, const fmpz_mod_mpoly_t A, const fmpz_mod_mpoly_ctx_t ctx)

Set f to a factorization of A where the bases are irreducible.