Content¶

void
fmpz_mat_content
(fmpz_t mat_gcd, const fmpz_mat_t A)¶ Sets
mat_gcd
as the gcd of all the elements of the matrixA
. Returns 0 if the matrix is empty.
Description.
fmpz_mat_init
(fmpz_mat_t mat, slong rows, slong cols)¶Initialises a matrix with the given number of rows and columns for use.
fmpz_mat_clear
(fmpz_mat_t mat)¶Clears the given matrix.
fmpz_mat_set
(fmpz_mat_t mat1, const fmpz_mat_t mat2)¶Sets mat1
to a copy of mat2
. The dimensions of
mat1
and mat2
must be the same.
fmpz_mat_init_set
(fmpz_mat_t mat, const fmpz_mat_t src)¶Initialises the matrix mat
to the same size as src
and
sets it to a copy of src
.
fmpz_mat_swap
(fmpz_mat_t mat1, fmpz_mat_t mat2)¶Swaps two matrices. The dimensions of mat1
and mat2
are allowed to be different.
fmpz_mat_swap_entrywise
(fmpz_mat_t mat1, fmpz_mat_t mat2)¶Swaps two matrices by swapping the individual entries rather than swapping the contents of the structs.
fmpz_mat_entry
(fmpz_mat_t mat, slong i, slong j)¶Returns a reference to the entry of mat
at row \(i\) and column \(j\).
This reference can be passed as an input or output variable to any
function in the fmpz
module for direct manipulation.
Both \(i\) and \(j\) must not exceed the dimensions of the matrix.
This function is implemented as a macro.
fmpz_mat_zero
(fmpz_mat_t mat)¶Sets all entries of mat
to 0.
fmpz_mat_one
(fmpz_mat_t mat)¶Sets mat
to the unit matrix, having ones on the main diagonal
and zeroes elsewhere. If mat
is nonsquare, it is set to the
truncation of a unit matrix.
fmpz_mat_swap_rows
(fmpz_mat_t mat, slong * perm, slong r, slong s)¶Swaps rows r
and s
of mat
. If perm
is nonNULL
, the
permutation of the rows will also be applied to perm
.
fmpz_mat_swap_cols
(fmpz_mat_t mat, slong * perm, slong r, slong s)¶Swaps columns r
and s
of mat
. If perm
is nonNULL
, the
permutation of the columns will also be applied to perm
.
fmpz_mat_invert_rows
(fmpz_mat_t mat, slong * perm)¶Swaps rows i
and r  i
of mat
for 0 <= i < r/2
, where
r
is the number of rows of mat
. If perm
is nonNULL
, the
permutation of the rows will also be applied to perm
.
fmpz_mat_invert_cols
(fmpz_mat_t mat, slong * perm)¶Swaps columns i
and c  i
of mat
for 0 <= i < c/2
, where
c
is the number of columns of mat
. If perm
is nonNULL
, the
permutation of the columns will also be applied to perm
.
fmpz_mat_window_init
(fmpz_mat_t window, const fmpz_mat_t mat, slong r1, slong c1, slong r2, slong c2)¶Initializes the matrix window
to be an r2  r1
by
c2  c1
submatrix of mat
whose (0,0)
entry
is the (r1, c1)
entry of mat
. The memory for the
elements of window
is shared with mat
.
fmpz_mat_window_clear
(fmpz_mat_t window)¶Clears the matrix window
and releases any memory that it
uses. Note that the memory to the underlying matrix that
window
points to is not freed.
fmpz_mat_randbits
(fmpz_mat_t mat, flint_rand_t state, flint_bitcnt_t bits)¶Sets the entries of mat
to random signed integers whose absolute
values have the given number of binary bits.
fmpz_mat_randtest
(fmpz_mat_t mat, flint_rand_t state, flint_bitcnt_t bits)¶Sets the entries of mat
to random signed integers whose
absolute values have a random number of bits up to the given number
of bits inclusive.
fmpz_mat_randintrel
(fmpz_mat_t mat, flint_rand_t state, flint_bitcnt_t bits)¶Sets mat
to be a random integer relations matrix, with
signed entries up to the given number of bits.
The number of columns of mat
must be equal to one more than
the number of rows. The format of the matrix is a set of random integers
in the left hand column and an identity matrix in the remaining square
submatrix.
fmpz_mat_randsimdioph
(fmpz_mat_t mat, flint_rand_t state, flint_bitcnt_t bits, flint_bitcnt_t bits2)¶Sets mat
to a random simultaneous diophantine matrix.
The matrix must be square. The top left entry is set to 2^bits2
.
The remainder of that row is then set to signed random integers of the
given number of binary bits. The remainder of the first column is zero.
Running down the rest of the diagonal are the values 2^bits
with
all remaining entries zero.
fmpz_mat_randntrulike
(fmpz_mat_t mat, flint_rand_t state, flint_bitcnt_t bits, ulong q)¶Sets a square matrix mat
of even dimension to a random
NTRU like matrix.
The matrix is broken into four square submatrices. The top left submatrix is set to the identity. The bottom left submatrix is set to the zero matrix. The bottom right submatrix is set to \(q\) times the identity matrix. Finally the top right submatrix has the following format. A random vector \(h\) of length \(r/2\) is created, with random signed entries of the given number of bits. Then entry \((i, j)\) of the submatrix is set to \(h[i + j \bmod{r/2}]\).
fmpz_mat_randntrulike2
(fmpz_mat_t mat, flint_rand_t state, flint_bitcnt_t bits, ulong q)¶Sets a square matrix mat
of even dimension to a random
NTRU like matrix.
The matrix is broken into four square submatrices. The top left submatrix is set to \(q\) times the identity matrix. The top right submatrix is set to the zero matrix. The bottom right submatrix is set to the identity matrix. Finally the bottom left submatrix has the following format. A random vector \(h\) of length \(r/2\) is created, with random signed entries of the given number of bits. Then entry \((i, j)\) of the submatrix is set to \(h[i + j \bmod{r/2}]\).
fmpz_mat_randajtai
(fmpz_mat_t mat, flint_rand_t state, double alpha)¶Sets a square matrix mat
to a random ajtai matrix.
The diagonal entries \((i, i)\) are set to a random entry in the range
\([1, 2^{b1}]\) inclusive where \(b = \lfloor(2 r  i)^\alpha\rfloor\) for some
double parameter~`alpha`. The entries below the diagonal in column~`i`
are set to a random entry in the range \((2^b + 1, 2^b  1)\) whilst the
entries to the right of the diagonal in row~`i` are set to zero.
fmpz_mat_randpermdiag
(fmpz_mat_t mat, flint_rand_t state, const fmpz * diag, slong n)¶Sets mat
to a random permutation of the rows and columns of a
given diagonal matrix. The diagonal matrix is specified in the form of
an array of the \(n\) initial entries on the main diagonal.
The return value is \(0\) or \(1\) depending on whether the permutation is even or odd.
fmpz_mat_randrank
(fmpz_mat_t mat, flint_rand_t state, slong rank, flint_bitcnt_t bits)¶Sets mat
to a random sparse matrix with the given rank,
having exactly as many nonzero elements as the rank, with the
nonzero elements being random integers of the given bit size.
The matrix can be transformed into a dense matrix with unchanged
rank by subsequently calling fmpz_mat_randops()
.
fmpz_mat_randdet
(fmpz_mat_t mat, flint_rand_t state, const fmpz_t det)¶Sets mat
to a random sparse matrix with minimal number of
nonzero entries such that its determinant has the given value.
Note that the matrix will be zero if det
is zero.
In order to generate a nonzero singular matrix, the function
fmpz_mat_randrank()
can be used.
The matrix can be transformed into a dense matrix with unchanged
determinant by subsequently calling fmpz_mat_randops()
.
fmpz_mat_randops
(fmpz_mat_t mat, flint_rand_t state, slong count)¶Randomises mat
by performing elementary row or column operations.
More precisely, at most count
random additions or subtractions of
distinct rows and columns will be performed. This leaves the rank
(and for square matrices, the determinant) unchanged.
fmpz_mat_fprint
(FILE * file, const fmpz_mat_t mat)¶Prints the given matrix to the stream file
. The format is
the number of rows, a space, the number of columns, two spaces, then
a space separated list of coefficients, one row after the other.
In case of success, returns a positive value; otherwise, returns a nonpositive value.
fmpz_mat_fprint_pretty
(FILE * file, const fmpz_mat_t mat)¶Prints the given matrix to the stream file
. The format is an
opening square bracket then on each line a row of the matrix, followed
by a closing square bracket. Each row is written as an opening square
bracket followed by a space separated list of coefficients followed
by a closing square bracket.
In case of success, returns a positive value; otherwise, returns a nonpositive value.
fmpz_mat_print
(const fmpz_mat_t mat)¶Prints the given matrix to the stream stdout
. For further
details, see fmpz_mat_fprint()
.
fmpz_mat_print_pretty
(const fmpz_mat_t mat)¶Prints the given matrix to stdout
. For further details,
see fmpz_mat_fprint_pretty()
.
fmpz_mat_fread
(FILE* file, fmpz_mat_t mat)¶Reads a matrix from the stream file
, storing the result
in mat
. The expected format is the number of rows, a
space, the number of columns, two spaces, then a space separated
list of coefficients, one row after the other.
In case of success, returns a positive number. In case of failure, returns a nonpositive value.
fmpz_mat_read
(fmpz_mat_t mat)¶Reads a matrix from stdin
, storing the result
in mat
.
In case of success, returns a positive number. In case of failure, returns a nonpositive value.
fmpz_mat_equal
(const fmpz_mat_t mat1, const fmpz_mat_t mat2)¶Returns a nonzero value if mat1
and mat2
have
the same dimensions and entries, and zero otherwise.
fmpz_mat_is_zero
(const fmpz_mat_t mat)¶Returns a nonzero value if all entries mat
are zero, and
otherwise returns zero.
fmpz_mat_is_one
(const fmpz_mat_t mat)¶Returns a nonzero value if mat
is the unit matrix or the truncation
of a unit matrix, and otherwise returns zero.
fmpz_mat_is_empty
(const fmpz_mat_t mat)¶Returns a nonzero value if the number of rows or the number of
columns in mat
is zero, and otherwise returns
zero.
fmpz_mat_is_square
(const fmpz_mat_t mat)¶Returns a nonzero value if the number of rows is equal to the
number of columns in mat
, and otherwise returns zero.
fmpz_mat_is_zero_row
(const fmpz_mat_t mat, slong i)¶Returns a nonzero value if row \(i\) of mat
is zero.
fmpz_mat_col_equal
(fmpz_mat_t M, slong m, slong n)¶Returns \(1\) if columns \(m\) and \(n\) of the matrix \(M\) are equal, otherwise returns \(0\).
fmpz_mat_row_equal
(fmpz_mat_t M, slong m, slong n)¶Returns \(1\) if rows \(m\) and \(n\) of the matrix \(M\) are equal, otherwise returns \(0\).
fmpz_mat_transpose
(fmpz_mat_t B, const fmpz_mat_t A)¶Sets \(B\) to \(A^T\), the transpose of \(A\). Dimensions must be compatible. \(A\) and \(B\) are allowed to be the same object if \(A\) is a square matrix.
fmpz_mat_concat_vertical
(fmpz_mat_t res, const fmpz_mat_t mat1, const fmpz_mat_t mat2)¶Sets res
to vertical concatenation of (mat1
, mat2
)
in that order. Matrix dimensions : mat1
: \(m \times n\),
mat2
: \(k \times n\), res
: \((m + k) \times n\).
fmpz_mat_concat_horizontal
(fmpz_mat_t res, const fmpz_mat_t mat1, const fmpz_mat_t mat2)¶Sets res
to horizontal concatenation of (mat1
, mat2
)
in that order. Matrix dimensions : mat1
: \(m \times n\),
mat2
: \(m \times k\), res
: \(m \times (n + k)\).
fmpz_mat_get_nmod_mat
(nmod_mat_t Amod, const fmpz_mat_t A)¶Sets the entries of Amod
to the entries of A
reduced
by the modulus of Amod
.
fmpz_mat_set_nmod_mat
(fmpz_mat_t A, const nmod_mat_t Amod)¶Sets the entries of Amod
to the residues in Amod
,
normalised to the interval \(m/2 <= r < m/2\) where \(m\) is the modulus.
fmpz_mat_set_nmod_mat_unsigned
(fmpz_mat_t A, const nmod_mat_t Amod)¶Sets the entries of Amod
to the residues in Amod
,
normalised to the interval \(0 <= r < m\) where \(m\) is the modulus.
fmpz_mat_CRT_ui
(fmpz_mat_t res, const fmpz_mat_t mat1, const fmpz_t m1, const nmod_mat_t mat2, int sign)¶Given mat1
with entries modulo m
and mat2
with modulus \(n\), sets res
to the CRT reconstruction modulo \(mn\)
with entries satisfying \(mn/2 <= c < mn/2\) (if sign = 1)
or \(0 <= c < mn\) (if sign = 0).
fmpz_mat_multi_mod_ui_precomp
(nmod_mat_t * residues, slong nres, const fmpz_mat_t mat, fmpz_comb_t comb, fmpz_comb_temp_t temp)¶Sets each of the nres
matrices in residues
to mat
reduced modulo the modulus of the respective matrix, given
precomputed comb
and comb_temp
structures.
fmpz_mat_multi_mod_ui
(nmod_mat_t * residues, slong nres, const fmpz_mat_t mat)¶Sets each of the nres
matrices in residues
to mat
reduced modulo the modulus of the respective matrix.
This function is provided for convenience purposes.
For reducing or reconstructing multiple integer matrices over the same
set of moduli, it is faster to use\ fmpz_mat_multi_mod_precomp
.
fmpz_mat_multi_CRT_ui_precomp
(fmpz_mat_t mat, nmod_mat_t * const residues, slong nres, fmpz_comb_t comb, fmpz_comb_temp_t temp, int sign)¶Reconstructs mat
from its images modulo the nres
matrices
in residues
, given precomputed comb
and comb_temp
structures.
fmpz_mat_multi_CRT_ui
(fmpz_mat_t mat, nmod_mat_t * const residues, slong nres, int sign)¶Reconstructs mat
from its images modulo the nres
matrices
in residues
.
This function is provided for convenience purposes.
For reducing or reconstructing multiple integer matrices over the same
set of moduli, it is faster to use fmpz_mat_multi_CRT_ui_precomp()
.
fmpz_mat_add
(fmpz_mat_t C, const fmpz_mat_t A, const fmpz_mat_t B)¶Sets C
to the elementwise sum \(A + B\). All inputs must
be of the same size. Aliasing is allowed.
fmpz_mat_sub
(fmpz_mat_t C, const fmpz_mat_t A, const fmpz_mat_t B)¶Sets C
to the elementwise difference \(A  B\). All inputs must
be of the same size. Aliasing is allowed.
fmpz_mat_neg
(fmpz_mat_t B, const fmpz_mat_t A)¶Sets B
to the elementwise negation of A
. Both inputs
must be of the same size. Aliasing is allowed.
fmpz_mat_scalar_mul_si
(fmpz_mat_t B, const fmpz_mat_t A, slong c)¶fmpz_mat_scalar_mul_ui
(fmpz_mat_t B, const fmpz_mat_t A, ulong c)¶fmpz_mat_scalar_mul_fmpz
(fmpz_mat_t B, const fmpz_mat_t A, const fmpz_t c)¶Set B = A*c
where A
is an fmpz_mat_t
and c
is a scalar respectively of type slong
, ulong
,
or fmpz_t
. The dimensions of A
and B
must
be compatible.
fmpz_mat_scalar_addmul_si
(fmpz_mat_t B, const fmpz_mat_t A, slong c)¶fmpz_mat_scalar_addmul_ui
(fmpz_mat_t B, const fmpz_mat_t A, ulong c)¶fmpz_mat_scalar_addmul_fmpz
(fmpz_mat_t B, const fmpz_mat_t A, const fmpz_t c)¶Set B = B + A*c
where A
is an fmpz_mat_t
and c
is a scalar respectively of type slong
, ulong
,
or fmpz_t
. The dimensions of A
and B
must
be compatible.
fmpz_mat_scalar_submul_si
(fmpz_mat_t B, const fmpz_mat_t A, slong c)¶fmpz_mat_scalar_submul_ui
(fmpz_mat_t B, const fmpz_mat_t A, ulong c)¶fmpz_mat_scalar_submul_fmpz
(fmpz_mat_t B, const fmpz_mat_t A, const fmpz_t c)¶Set B = B  A*c
where A
is an fmpz_mat_t
and c
is a scalar respectively of type slong
, ulong
,
or fmpz_t
. The dimensions of A
and B
must
be compatible.
fmpz_mat_scalar_addmul_nmod_mat_ui
(fmpz_mat_t B, const nmod_mat_t A, ulong c)¶fmpz_mat_scalar_addmul_nmod_mat_fmpz
(fmpz_mat_t B, const nmod_mat_t A, const fmpz_t c)¶Set B = B + A*c
where A
is an nmod_mat_t
and c
is a scalar respectively of type ulong
or fmpz_t
.
The dimensions of A
and B
must be compatible.
fmpz_mat_scalar_divexact_si
(fmpz_mat_t B, const fmpz_mat_t A, slong c)¶fmpz_mat_scalar_divexact_ui
(fmpz_mat_t B, const fmpz_mat_t A, ulong c)¶fmpz_mat_scalar_divexact_fmpz
(fmpz_mat_t B, const fmpz_mat_t A, const fmpz_t c)¶Set A = B / c
, where B
is an fmpz_mat_t
and c
is a scalar respectively of type slong
, ulong
,
or fmpz_t
, which is assumed to divide all elements of
B
exactly.
fmpz_mat_scalar_mul_2exp
(fmpz_mat_t B, const fmpz_mat_t A, ulong exp)¶Set the matrix B
to the matrix A
, of the same dimensions,
multiplied by \(2^{exp}\).
fmpz_mat_scalar_tdiv_q_2exp
(fmpz_mat_t B, const fmpz_mat_t A, ulong exp)¶Set the matrix B
to the matrix A
, of the same dimensions,
divided by \(2^{exp}\), rounding down towards zero.
fmpz_mat_scalar_smod
(fmpz_mat_t B, const fmpz_mat_t A, const fmpz_t P)¶Set the matrix B
to the matrix A
, of the same dimensions,
with each entry reduced modulo \(P\) in the symmetric moduli system. We
require \(P > 0\).
fmpz_mat_mul
(fmpz_mat_t C, const fmpz_mat_t A, const fmpz_mat_t B)¶Sets C
to the matrix product \(C = A B\). The matrices must have
compatible dimensions for matrix multiplication. Aliasing
is allowed.
This function automatically switches between classical and multimodular multiplication, based on a heuristic comparison of the dimensions and entry sizes.
fmpz_mat_mul_classical
(fmpz_mat_t C, const fmpz_mat_t A, const fmpz_mat_t B)¶Sets C
to the matrix product \(C = A B\) computed using
classical matrix algorithm.
The matrices must have compatible dimensions for matrix multiplication. No aliasing is allowed.
fmpz_mat_mul_strassen
(fmpz_mat_t C, const fmpz_mat_t A, const fmpz_mat_t B)¶Sets \(C = AB\). Dimensions must be compatible for matrix multiplication. \(C\) is not allowed to be aliased with \(A\) or \(B\). Uses Strassen multiplication (the StrassenWinograd variant).
_fmpz_mat_mul_multi_mod
(fmpz_mat_t C, const fmpz_mat_t A, const fmpz_mat_t B, int sign, flint_bitcnt_t bits)¶fmpz_mat_mul_multi_mod
(fmpz_mat_t C, const fmpz_mat_t A, const fmpz_mat_t B)¶Sets C
to the matrix product \(C = AB\) computed using a multimodular
algorithm. \(C\) is computed modulo several small prime numbers
and reconstructed using the Chinese Remainder Theorem. This generally
becomes more efficient than classical multiplication for large matrices.
The absolute value of the elements of \(C\) should be \(< 2^{\text{bits}}\),
and sign
should be \(0\) if the entries of \(C\) are known to be nonnegative
and \(1\) otherwise. The function
fmpz_mat_mul_multi_mod()
calculates a rigorous bound automatically.
If the default bound is too pessimistic, _fmpz_mat_mul_multi_mod()
can be used with a custom bound.
The matrices must have compatible dimensions for matrix multiplication. No aliasing is allowed.
fmpz_mat_mul_blas
(fmpz_mat_t C, const fmpz_mat_t A, const fmpz_mat_t B)¶Tries to set \(C = AB\) using BLAS and returns \(1\) for success and \(0\) for failure. Dimensions must be compatible for matrix multiplication. No aliasing is allowed. This function currently will fail if the matrices are empty, their dimensions are too large, or their max bits size is over one million bits.
fmpz_mat_sqr
(fmpz_mat_t B, const fmpz_mat_t A)¶Sets B
to the square of the matrix A
, which must be
a square matrix. Aliasing is allowed.
The function calls fmpz_mat_mul()
for dimensions less than 12 and
calls fmpz_mat_sqr_bodrato()
for cases in which the latter is faster.
fmpz_mat_sqr_bodrato
(fmpz_mat_t B, const fmpz_mat_t A)¶Sets B
to the square of the matrix A
, which must be
a square matrix. Aliasing is allowed.
The bodrato algorithm is described in [Bodrato2010].
It is highly efficient for squaring matrices which satisfy both the
following conditions : (a) large elements (b) dimensions less than 150.
fmpz_mat_pow
(fmpz_mat_t B, const fmpz_mat_t A, ulong e)¶Sets B
to the matrix A
raised to the power e
,
where A
must be a square matrix. Aliasing is allowed.
_fmpz_mat_mul_small
(fmpz_mat_t C, const fmpz_mat_t A, const fmpz_mat_t B)¶This internal function sets \(C\) to the matrix product \(C = A B\) computed using classical matrix algorithm assuming that all entries of \(A\) and \(B\) are small, that is, have bits ` le FLINT_BITS  2`. No aliasing is allowed.
_fmpz_mat_mul_double_word
(fmpz_mat_t C, const fmpz_mat_t A, const fmpz_mat_t B)¶fmpz_mat_mul_fmpz_vec
(fmpz * c, const fmpz_mat_t A, const fmpz * b, slong blen)¶fmpz_mat_mul_fmpz_vec_ptr
(fmpz * const * c, const fmpz_mat_t A, const fmpz * const * b, slong blen)¶Compute a matrixvector product of A
and (b, blen)
and store the result in c
.
The vector (b, blen)
is either truncated or zeroextended to the number of columns of A
.
The number entries written to c
is always equal to the number of rows of A
.
fmpz_mat_fmpz_vec_mul
(fmpz * c, const fmpz * a, slong alen, const fmpz_mat_t B)¶fmpz_mat_fmpz_vec_mul_ptr
(fmpz * const * c, const fmpz * const * a, slong alen, const fmpz_mat_t B)¶Compute a vectormatrix product of (a, alen)
and B
and and store the result in c
.
The vector (a, alen)
is either truncated or zeroextended to the number of rows of B
.
The number entries written to c
is always equal to the number of columns of B
.
fmpz_mat_inv
(fmpz_mat_t Ainv, fmpz_t den, const fmpz_mat_t A)¶Sets (Ainv
, den
) to the inverse matrix of A
.
Returns 1 if A
is nonsingular and 0 if A
is singular.
Aliasing of Ainv
and A
is allowed.
The denominator is not guaranteed to be minimal, but is guaranteed
to be a divisor of the determinant of A
.
This function uses a direct formula for matrices of size two or less, and otherwise solves for the identity matrix using fractionfree LU decomposition.
fmpz_mat_kronecker_product
(fmpz_mat_t C, const fmpz_mat_t A, const fmpz_mat_t B)¶Sets C
to the Kronecker product of A
and B
.
fmpz_mat_content
(fmpz_t mat_gcd, const fmpz_mat_t A)¶Sets mat_gcd
as the gcd of all the elements of the matrix A
.
Returns 0 if the matrix is empty.
fmpz_mat_trace
(fmpz_t trace, const fmpz_mat_t mat)¶Computes the trace of the matrix, i.e. the sum of the entries on the main diagonal. The matrix is required to be square.
fmpz_mat_det
(fmpz_t det, const fmpz_mat_t A)¶Sets det
to the determinant of the square matrix \(A\).
The matrix of dimension \(0 \times 0\) is defined to have determinant 1.
This function automatically chooses between fmpz_mat_det_cofactor()
,
fmpz_mat_det_bareiss()
, fmpz_mat_det_modular()
and
fmpz_mat_det_modular_accelerated()
(with proved
= 1), depending on the size of the matrix
and its entries.
fmpz_mat_det_cofactor
(fmpz_t det, const fmpz_mat_t A)¶Sets det
to the determinant of the square matrix \(A\)
computed using direct cofactor expansion. This function only
supports matrices up to size \(4 \times 4\).
fmpz_mat_det_bareiss
(fmpz_t det, const fmpz_mat_t A)¶Sets det
to the determinant of the square matrix \(A\)
computed using the Bareiss algorithm. A copy of the input matrix is
row reduced using fractionfree Gaussian elimination, and the
determinant is read off from the last element on the main
diagonal.
fmpz_mat_det_modular
(fmpz_t det, const fmpz_mat_t A, int proved)¶Sets det
to the determinant of the square matrix \(A\)
(if proved
= 1), or a probabilistic value for the
determinant (proved
= 0), computed using a multimodular
algorithm.
The determinant is computed modulo several small primes and
reconstructed using the Chinese Remainder Theorem.
With proved
= 1, sufficiently many primes are chosen
to satisfy the bound computed by fmpz_mat_det_bound
.
With proved
= 0, the determinant is considered determined
if it remains unchanged modulo several consecutive primes
(currently if their product exceeds \(2^{100}\)).
fmpz_mat_det_modular_accelerated
(fmpz_t det, const fmpz_mat_t A, int proved)¶Sets det
to the determinant of the square matrix \(A\)
(if proved
= 1), or a probabilistic value for the
determinant (proved
= 0), computed using a multimodular
algorithm.
This function uses the same basic algorithm as fmpz_mat_det_modular
,
but instead of computing \(\det(A)\) directly, it generates a divisor \(d\)
of \(\det(A)\) and then computes \(x = \det(A) / d\) modulo several
small primes not dividing \(d\). This typically accelerates the
computation by requiring fewer primes for large matrices, since \(d\)
with high probability will be nearly as large as the determinant.
This trick is described in [AbbottBronsteinMulders1999].
fmpz_mat_det_modular_given_divisor
(fmpz_t det, const fmpz_mat_t A, const fmpz_t d, int proved)¶Given a positive divisor \(d\) of \(\det(A)\), sets det
to the
determinant of the square matrix \(A\) (if proved
= 1), or a
probabilistic value for the determinant (proved
= 0), computed
using a multimodular algorithm.
fmpz_mat_det_bound
(fmpz_t bound, const fmpz_mat_t A)¶Sets bound
to a nonnegative integer \(B\) such that
\(\det(A) \le B\). Assumes \(A\) to be a square matrix.
The bound is computed from the Hadamard inequality
\(\det(A) \le \prod \a_i\_2\) where the product is taken
over the rows \(a_i\) of \(A\).
fmpz_mat_det_bound()
but excludes zero columns. For use with
nonsquare matrices.fmpz_mat_det_divisor
(fmpz_t d, const fmpz_mat_t A)¶Sets \(d\) to some positive divisor of the determinant of the given square matrix \(A\), if the determinant is nonzero. If \(\det(A) = 0\), \(d\) will always be set to zero.
A divisor is obtained by solving \(Ax = b\) for an arbitrarily chosen righthand side \(b\) using Dixon’s algorithm and computing the least common multiple of the denominators in \(x\). This yields a divisor \(d\) such that \(\det(A) / d\) is tiny with very high probability.
fmpz_mat_similarity
(fmpz_mat_t A, slong r, fmpz_t d)¶Applies a similarity transform to the \(n\times n\) matrix \(M\) inplace.
If \(P\) is the \(n\times n\) identity matrix the zero entries of whose row \(r\) (\(0\)indexed) have been replaced by \(d\), this transform is equivalent to \(M = P^{1}MP\).
Similarity transforms preserve the determinant, characteristic polynomial and minimal polynomial.
_fmpz_mat_charpoly_berkowitz
(fmpz * cp, const fmpz_mat_t mat)¶Sets (cp, n+1)
to the characteristic polynomial of
an \(n \times n\) square matrix.
fmpz_mat_charpoly_berkowitz
(fmpz_poly_t cp, const fmpz_mat_t mat)¶Computes the characteristic polynomial of length \(n + 1\) of an \(n \times n\) square matrix. Uses an \(O(n^4)\) algorithm based on the method of Berkowitz.
_fmpz_mat_charpoly_modular
(fmpz * cp, const fmpz_mat_t mat)¶Sets (cp, n+1)
to the characteristic polynomial of
an \(n \times n\) square matrix.
fmpz_mat_charpoly_modular
(fmpz_poly_t cp, const fmpz_mat_t mat)¶Computes the characteristic polynomial of length \(n + 1\) of an \(n \times n\) square matrix. Uses a modular method based on an \(O(n^3)\) method over \(\mathbb{Z}/n\mathbb{Z}\).
_fmpz_mat_charpoly
(fmpz * cp, const fmpz_mat_t mat)¶Sets (cp, n+1)
to the characteristic polynomial of
an \(n \times n\) square matrix.
fmpz_mat_charpoly
(fmpz_poly_t cp, const fmpz_mat_t mat)¶Computes the characteristic polynomial of length \(n + 1\) of an \(n \times n\) square matrix.
_fmpz_mat_minpoly_modular
(fmpz * cp, const fmpz_mat_t mat)¶Sets (cp, n+1)
to the modular polynomial of
an \(n \times n\) square matrix and returns its length.
fmpz_mat_minpoly_modular
(fmpz_poly_t cp, const fmpz_mat_t mat)¶Computes the minimal polynomial of an \(n \times n\) square matrix. Uses a modular method based on an average time \(O~(n^3)\), worst case \(O(n^4)\) method over \(\mathbb{Z}/n\mathbb{Z}\).
_fmpz_mat_minpoly
(fmpz * cp, const fmpz_mat_t mat)¶Sets cp
to the minimal polynomial of an \(n \times n\) square
matrix and returns its length.
fmpz_mat_minpoly
(fmpz_poly_t cp, const fmpz_mat_t mat)¶Computes the minimal polynomial of an \(n \times n\) square matrix.
fmpz_mat_rank
(const fmpz_mat_t A)¶Returns the rank, that is, the number of linearly independent columns (equivalently, rows), of \(A\). The rank is computed by row reducing a copy of \(A\).
fmpz_mat_col_partition
(slong * part, fmpz_mat_t M, int short_circuit)¶Returns the number \(p\) of distinct columns of \(M\) (or \(0\) if the flag
short_circuit
is set and this number is greater than the number
of rows of \(M\)). The entries of array part
are set to values in
\([0, p)\) such that two entries of part are equal iff the corresponding
columns of \(M\) are equal. This function is used in van Hoeij polynomial
factoring.
The following functions allow solving matrixmatrix equations \(AX = B\)
where the system matrix \(A\) is square and has full rank. The solving
is implicitly done over the field of rational numbers: except
where otherwise noted, an integer matrix \(\hat X\) and a separate
denominator \(d\) (den
) are computed such that \(A(\hat X/d) = b\),
equivalently such that \(A\hat X = bd\) holds over the integers.
No guarantee is made that the numerators and denominator
are reduced to lowest terms, but the denominator is always guaranteed
to be a divisor of the determinant of \(A\). If \(A\) is singular,
den
will be set to zero and the elements of the solution
vector or matrix will have undefined values. No aliasing is
allowed between arguments.
fmpz_mat_solve
(fmpz_mat_t X, fmpz_t den, const fmpz_mat_t A, const fmpz_mat_t B)¶Solves the equation \(AX = B\) for nonsingular \(A\). More precisely, computes
(X
, den
) such that \(AX = B \times \operatorname{den}\).
Returns 1 if \(A\) is nonsingular and 0 if \(A\) is singular.
The computed denominator will not generally be minimal.
This function uses Cramer’s rule for small systems and fractionfree LU decomposition followed by fractionfree forward and back substitution for larger systems.
Note that for very large systems, it is faster to compute a modular
solution using fmpz_mat_solve_dixon
.
fmpz_mat_solve_fflu
(fmpz_mat_t X, fmpz_t den, const fmpz_mat_t A, const fmpz_mat_t B)¶Solves the equation \(AX = B\) for nonsingular \(A\). More precisely, computes
(X
, den
) such that \(AX = B \times \operatorname{den}\).
Returns 1 if \(A\) is nonsingular and 0 if \(A\) is singular.
The computed denominator will not generally be minimal.
Uses fractionfree LU decomposition followed by fractionfree forward and back substitution.
fmpz_mat_solve_fflu_precomp
(fmpz_mat_t X, const slong * perm, const fmpz_mat_t FFLU, const fmpz_mat_t B)¶Performs fractionfree forward and back substitution given a precomputed fractionfree LU decomposition and corresponding permutation. If no impossible division is encountered, the function returns \(1\). This does not mean the system has a solution, however a return value of \(0\) can only occur if the system is insoluble.
If the return value is \(1\) and \(r\) is the rank of the matrix \(A\) whose FFLU we have, then the first \(r\) rows of \(p(A)y = p(b)d\) hold, where \(d\) is the denominator of the FFLU. The remaining rows must be checked by the caller.
fmpz_mat_solve_cramer
(fmpz_mat_t X, fmpz_t den, const fmpz_mat_t A, const fmpz_mat_t B)¶Solves the equation \(AX = B\) for nonsingular \(A\). More precisely, computes
(X
, den
) such that \(AX = B \times \operatorname{den}\).
Returns 1 if \(A\) is nonsingular and 0 if \(A\) is singular.
Uses Cramer’s rule. Only systems of size up to \(3 \times 3\) are allowed.
fmpz_mat_solve_bound
(fmpz_t N, fmpz_t D, const fmpz_mat_t A, const fmpz_mat_t B)¶Assuming that \(A\) is nonsingular, computes integers \(N\) and \(D\) such that the reduced numerators and denominators \(n/d\) in \(A^{1} B\) satisfy the bounds \(0 \le n \le N\) and \(0 \le d \le D\).
fmpz_mat_solve_dixon
(fmpz_mat_t X, fmpz_t M, const fmpz_mat_t A, const fmpz_mat_t B)¶Solves \(AX = B\) given a nonsingular square matrix \(A\) and a matrix \(B\) of compatible dimensions, using a modular algorithm. In particular, Dixon’s padic lifting algorithm is used (currently a nonadaptive version). This is generally the preferred method for large dimensions.
More precisely, this function computes an integer \(M\) and an integer
matrix \(X\) such that \(AX = B \bmod M\) and such that all the reduced
numerators and denominators of the elements \(x = p/q\) in the full
solution satisfy \(2pq < M\). As such, the explicit rational solution
matrix can be recovered uniquely by passing the output of this
function to fmpq_mat_set_fmpz_mat_mod
.
A nonzero value is returned if \(A\) is nonsingular. If \(A\) is singular, zero is returned and the values of the output variables will be undefined.
Aliasing between input and output matrices is allowed.
_fmpz_mat_solve_dixon_den
(fmpz_mat_t X, fmpz_t den, const fmpz_mat_t A, const fmpz_mat_t B, const nmod_mat_t Ainv, mp_limb_t p, const fmpz_t N, const fmpz_t D)¶Solves the equation \(AX = B\) for nonsingular \(A\). More precisely, computes
(X
, den
) such that \(AX = B \times \operatorname{den}\) using a
p
adic algorithm for the supplied prime p
. The values N
and
D
are absolute value bounds for the numerator and denominator of the
solution.
Uses the Dixon lifting algorithm with early termination once the lifting stabilises.
fmpz_mat_solve_dixon_den
(fmpz_mat_t X, fmpz_t den, const fmpz_mat_t A, const fmpz_mat_t B)¶Solves the equation \(AX = B\) for nonsingular \(A\). More precisely, computes
(X
, den
) such that \(AX = B \times \operatorname{den}\).
Returns 1 if \(A\) is nonsingular and 0 if \(A\) is singular.
The computed denominator will not generally be minimal.
Uses the Dixon lifting algorithm with early termination once the lifting stabilises.
fmpz_mat_solve_multi_mod_den
(fmpz_mat_t X, fmpz_t den, const fmpz_mat_t A, const fmpz_mat_t B)¶Solves the equation \(AX = B\) for nonsingular \(A\). More precisely, computes
(X
, den
) such that \(AX = B \times \operatorname{den}\).
Returns 1 if \(A\) is nonsingular and 0 if \(A\) is singular.
The computed denominator will not generally be minimal.
Uses a Chinese remainder algorithm with early termination once the lifting stabilises.
fmpz_mat_can_solve_multi_mod_den
(fmpz_mat_t X, fmpz_t den, const fmpz_mat_t A, const fmpz_mat_t B)¶Returns \(1\) if the system \(AX = B\) can be solved. If so it computes
(X
, den
) such that \(AX = B \times \operatorname{den}\). The
computed denominator will not generally be minimal.
Uses a Chinese remainder algorithm.
Note that the matrices \(A\) and \(B\) may have any shape as long as they have the same number of rows.
fmpz_mat_can_solve_fflu
(fmpz_mat_t X, fmpz_t den, const fmpz_mat_t A, const fmpz_mat_t B)¶Returns \(1\) if the system \(AX = B\) can be solved. If so it computes
(X
, den
) such that \(AX = B \times \operatorname{den}\). The
computed denominator will not generally be minimal.
Uses a fraction free LU decomposition algorithm.
Note that the matrices \(A\) and \(B\) may have any shape as long as they have the same number of rows.
fmpz_mat_can_solve
(fmpz_mat_t X, fmpz_t den, const fmpz_mat_t A, const fmpz_mat_t B)¶Returns \(1\) if the system \(AX = B\) can be solved. If so it computes
(X
, den
) such that \(AX = B \times \operatorname{den}\). The
computed denominator will not generally be minimal.
Note that the matrices \(A\) and \(B\) may have any shape as long as they have the same number of rows.
fmpz_mat_find_pivot_any
(const fmpz_mat_t mat, slong start_row, slong end_row, slong c)¶Attempts to find a pivot entry for row reduction.
Returns a row index \(r\) between start_row
(inclusive) and
stop_row
(exclusive) such that column \(c\) in mat
has
a nonzero entry on row \(r\), or returns 1 if no such entry exists.
This implementation simply chooses the first nonzero entry from it encounters. This is likely to be a nearly optimal choice if all entries in the matrix have roughly the same size, but can lead to unnecessary coefficient growth if the entries vary in size.
fmpz_mat_fflu
(fmpz_mat_t B, fmpz_t den, slong * perm, const fmpz_mat_t A, int rank_check)¶Uses fractionfree Gaussian elimination to set (B
, den
) to a
fractionfree LU decomposition of A
and returns the
rank of A
. Aliasing of A
and B
is allowed.
Pivot elements are chosen with fmpz_mat_find_pivot_any
.
If perm
is nonNULL
, the permutation of
rows in the matrix will also be applied to perm
.
If rank_check
is set, the function aborts and returns 0 if the
matrix is detected not to have full rank without completing the
elimination.
The denominator den
is set to \(\pm \operatorname{det}(S)\) where
\(S\) is an appropriate submatrix of \(A\) (\(S = A\) if \(A\) is square)
and the sign is decided by the parity of the permutation. Note that the
determinant is not generally the minimal denominator.
The fractionfree LU decomposition is defined in [NakTurWil1997].
fmpz_mat_rref
(fmpz_mat_t B, fmpz_t den, const fmpz_mat_t A)¶Sets (B
, den
) to the reduced row echelon form of A
and returns the rank of A
. Aliasing of A
and B
is allowed.
The algorithm used chooses between fmpz_mat_rref_fflu
and
fmpz_mat_rref_mul
based on the dimensions of the input matrix.
fmpz_mat_rref_fflu
(fmpz_mat_t B, fmpz_t den, const fmpz_mat_t A)¶Sets (B
, den
) to the reduced row echelon form of A
and returns the rank of A
. Aliasing of A
and B
is allowed.
The algorithm proceeds by first computing a row echelon form using
fmpz_mat_fflu
. Letting the upper part of this matrix be
\((U  V) P\) where \(U\) is full rank upper triangular and \(P\) is a
permutation matrix, we obtain the rref by setting \(V\) to \(U^{1} V\)
using back substitution. Scaling each completed row in the back
substitution to the denominator den
, we avoid introducing
new fractions. This strategy is equivalent to the fractionfree
GaussJordan elimination in [NakTurWil1997], but faster since
only the part \(V\) corresponding to the null space has to be updated.
The denominator den
is set to \(\pm \operatorname{det}(S)\) where
\(S\) is an appropriate submatrix of \(A\) (\(S = A\) if \(A\) is square).
Note that the determinant is not generally the minimal denominator.
fmpz_mat_rref_mul
(fmpz_mat_t B, fmpz_t den, const fmpz_mat_t A)¶Sets (B
, den
) to the reduced row echelon form of A
and returns the rank of A
. Aliasing of A
and B
is allowed.
The algorithm works by computing the reduced row echelon form of A
modulo a prime \(p\) using nmod_mat_rref
. The pivot columns and rows
of this matrix will then define a nonsingular submatrix of A
,
nonsingular solving and matrix multiplication can then be used to determine
the reduced row echelon form of the whole of A
. This procedure is
described in [Stein2007].
fmpz_mat_is_in_rref_with_rank
(const fmpz_mat_t A, const fmpz_t den, slong rank)¶Checks that the matrix \(A/den\) is in reduced row echelon form of rank
rank
, returns 1 if so and 0 otherwise.
fmpz_mat_rref_mod
(slong * perm, fmpz_mat_t A, const fmpz_t p)¶Uses fractionfree GaussJordan elimination to set A
to its reduced row echelon form and returns the rank of A
.
All computations are done modulo p.
Pivot elements are chosen with fmpz_mat_find_pivot_any
.
If perm
is nonNULL
, the permutation of
rows in the matrix will also be applied to perm
.
fmpz_mat_strong_echelon_form_mod
(fmpz_mat_t A, const fmpz_t mod)¶Transforms \(A\) such that \(A\) modulo mod
is the strong echelon form
of the input matrix modulo mod
. The Howell form and the strong
echelon form are equal up to permutation of the rows, see [FieHof2014]
for a definition of the strong echelon form and the algorithm used here.
\(A\) must have at least as many rows as columns.
fmpz_mat_howell_form_mod
(nmod_mat_t A, const fmpz_t mod)¶Transforms \(A\) such that \(A\) modulo mod
is the Howell form of the
input matrix modulo mod
.
For a definition of the Howell form see [StoMul1998]. The Howell form
is computed by first putting \(A\) into strong echelon form and then ordering
the rows.
\(A\) must have at least as many rows as columns.
fmpz_mat_nullspace
(fmpz_mat_t B, const fmpz_mat_t A)¶Computes a basis for the right rational nullspace of \(A\) and returns the dimension of the nullspace (or nullity). \(B\) is set to a matrix with linearly independent columns and maximal rank such that \(AB = 0\) (i.e. \(Ab = 0\) for each column \(b\) in \(B\)), and the rank of \(B\) is returned.
In general, the entries in \(B\) will not be minimal: in particular, the pivot entries in \(B\) will generally differ from unity. \(B\) must be allocated with sufficient space to represent the result (at most \(n \times n\) where \(n\) is the number of column of \(A\)).
fmpz_mat_rref_fraction_free
(slong * perm, fmpz_mat_t B, fmpz_t den, const fmpz_mat_t A)¶Computes an integer matrix B
and an integer den
such that
B / den
is the unique row reduced echelon form (RREF) of A
and returns the rank, i.e. the number of nonzero rows in B
.
Aliasing of B
and A
is allowed, with an inplace
computation being more efficient. The size of B
must be
the same as that of A
.
The permutation order will be written to perm
unless this
argument is NULL
. That is, row i
of the output matrix will
correspond to row perm[i]
of the input matrix.
The denominator will always be a divisor of the determinant of (some submatrix of) \(A\), but is not guaranteed to be minimal or canonical in any other sense.
fmpz_mat_hnf
(fmpz_mat_t H, const fmpz_mat_t A)¶Computes an integer matrix H
such that H
is the unique (row)
Hermite normal form of A
. The algorithm used is selected from the
implementations in FLINT to be the one most likely to be optimal, based on
the characteristics of the input matrix.
Aliasing of H
and A
is allowed. The size of H
must be
the same as that of A
.
fmpz_mat_hnf_transform
(fmpz_mat_t H, fmpz_mat_t U, const fmpz_mat_t A)¶Computes an integer matrix H
such that H
is the unique (row)
Hermite normal form of A
along with the transformation matrix
U
such that \(UA = H\). The algorithm used is selected from the
implementations in FLINT as per fmpz_mat_hnf
.
Aliasing of H
and A
is allowed. The size of H
must be
the same as that of A
and U
must be square of compatible
dimension (having the same number of rows as A
).
fmpz_mat_hnf_classical
(fmpz_mat_t H, const fmpz_mat_t A)¶Computes an integer matrix H
such that H
is the unique (row)
Hermite normal form of A
. The algorithm used is straightforward and
is described, for example, in [Algorithm 2.4.4] [Coh1996].
Aliasing of H
and A
is allowed. The size of H
must be
the same as that of A
.
fmpz_mat_hnf_xgcd
(fmpz_mat_t H, const fmpz_mat_t A)¶Computes an integer matrix H
such that H
is the unique (row)
Hermite normal form of A
. The algorithm used is an improvement on the
basic algorithm and uses extended gcds to speed up computation, this method
is described, for example, in [Algorithm 2.4.5] [Coh1996].
Aliasing of H
and A
is allowed. The size of H
must be
the same as that of A
.
fmpz_mat_hnf_modular
(fmpz_mat_t H, const fmpz_mat_t A, const fmpz_t D)¶Computes an integer matrix H
such that H
is the unique (row)
Hermite normal form of the \(m\times n\) matrix A
, where A
is
assumed to be of rank \(n\) and D
is known to be a positive multiple of
the determinant of the nonzero rows of H
. The algorithm used here is
due to Domich, Kannan and Trotter [DomKanTro1987] and is also described
in [Algorithm 2.4.8] [Coh1996].
Aliasing of H
and A
is allowed. The size of H
must be
the same as that of A
.
fmpz_mat_hnf_modular_eldiv
(fmpz_mat_t A, const fmpz_t D)¶Transforms the \(m\times n\) matrix A
into Hermite normal form,
where A
is assumed to be of rank \(n\) and D
is known to be a
positive multiple of the largest elementary divisor of A
.
The algorithm used here is described in [FieHof2014].
fmpz_mat_hnf_minors
(fmpz_mat_t H, const fmpz_mat_t A)¶Computes an integer matrix H
such that H
is the unique (row)
Hermite normal form of the \(m\times n\) matrix A
, where A
is
assumed to be of rank \(n\). The algorithm used here is due to Kannan and
Bachem [KanBac1979] and takes the principal minors to Hermite normal
form in turn.
Aliasing of H
and A
is allowed. The size of H
must be
the same as that of A
.
fmpz_mat_hnf_pernet_stein
(fmpz_mat_t H, const fmpz_mat_t A, flint_rand_t state)¶Computes an integer matrix H
such that H
is the unique (row)
Hermite normal form of the \(m\times n\) matrix A
. The algorithm used
here is due to Pernet and Stein [PernetStein2010].
Aliasing of H
and A
is allowed. The size of H
must be
the same as that of A
.
fmpz_mat_is_in_hnf
(const fmpz_mat_t A)¶Checks that the given matrix is in Hermite normal form, returns 1 if so and 0 otherwise.
fmpz_mat_snf
(fmpz_mat_t S, const fmpz_mat_t A)¶Computes an integer matrix S
such that S
is the unique Smith
normal form of A
. The algorithm used is selected from the
implementations in FLINT to be the one most likely to be optimal, based on
the characteristics of the input matrix.
Aliasing of S
and A
is allowed. The size of S
must be
the same as that of A
.
fmpz_mat_snf_diagonal
(fmpz_mat_t S, const fmpz_mat_t A)¶Computes an integer matrix S
such that S
is the unique Smith
normal form of the diagonal matrix A
. The algorithm used simply takes
gcds of pairs on the diagonal in turn until the Smith form is obtained.
Aliasing of S
and A
is allowed. The size of S
must be
the same as that of A
.
fmpz_mat_snf_kannan_bachem
(fmpz_mat_t S, const fmpz_mat_t A)¶Computes an integer matrix S
such that S
is the unique Smith
normal form of the diagonal matrix A
. The algorithm used here is due
to Kannan and Bachem [KanBac1979]
Aliasing of S
and A
is allowed. The size of S
must be
the same as that of A
.
fmpz_mat_snf_iliopoulos
(fmpz_mat_t S, const fmpz_mat_t A, const fmpz_t mod)¶Computes an integer matrix S
such that S
is the unique Smith
normal form of the nonsingular \(n\times n\) matrix A
. The algorithm
used is due to Iliopoulos [Iliopoulos1989].
Aliasing of S
and A
is allowed. The size of S
must be
the same as that of A
.
fmpz_mat_is_in_snf
(const fmpz_mat_t A)¶Checks that the given matrix is in Smith normal form, returns 1 if so and 0 otherwise.
fmpz_mat_gram
(fmpz_mat_t B, const fmpz_mat_t A)¶Sets B
to the Gram matrix of the \(m\)dimensional lattice L
in
\(n\)dimensional Euclidean space \(R^n\) spanned by the rows of
the \(m \times n\) matrix A
. Dimensions must be compatible.
A
and B
are allowed to be the same object if A
is a
square matrix.
fmpz_mat_is_hadamard
(const fmpz_mat_t H)¶Returns nonzero iff \(H\) is a Hadamard matrix, meaning that it is a square matrix, only has entries that are \(\pm 1\), and satisfies \(H^T = n H^{1}\) where \(n\) is the matrix size.
fmpz_mat_hadamard
(fmpz_mat_t H)¶Attempts to set the matrix \(H\) to a Hadamard matrix, returning 1 if successful and 0 if unsuccessful.
A Hadamard matrix of size \(n\) can only exist if \(n\) is 1, 2, or a multiple of 4. It is not known whether a Hadamard matrix exists for every size that is a multiple of 4. This function uses the Paley construction, which succeeds for all \(n\) of the form \(n = 2^e\) or \(n = 2^e (q + 1)\) where \(q\) is an odd prime power. Orders \(n\) for which Hadamard matrices are known to exist but for which this construction fails are 92, 116, 156, … (OEIS A046116).
fmpz_mat_get_d_mat
(d_mat_t B, const fmpz_mat_t A)¶Sets the entries of B
as doubles corresponding to the entries of
A
, rounding down towards zero if the latter cannot be represented
exactly. The return value is 1 if any entry of A
is too large to
fit in the normal range of a double, and 0 otherwise.
fmpz_mat_get_d_mat_transpose
(d_mat_t B, const fmpz_mat_t A)¶Sets the entries of B
as doubles corresponding to the entries of
the transpose of A
, rounding down towards zero if the latter cannot
be represented exactly. The return value is 1 if any entry of A
is
too large to fit in the normal range of a double, and 0 otherwise.
fmpz_mat_get_mpf_mat
(mpf_mat_t B, const fmpz_mat_t A)¶Sets the entries of B
as mpfs corresponding to the entries of
A
.
fmpz_mat_chol_d
(d_mat_t R, const fmpz_mat_t A)¶Computes R
, the Cholesky factor of a symmetric, positive definite
matrix A
using the Cholesky decomposition process. (Sets R
such that \(A = RR^{T}\) where R
is a lower triangular matrix.)
fmpz_mat_is_reduced
(const fmpz_mat_t A, double delta, double eta)¶Returns a nonzero value if the basis A
is LLLreduced with factor
(delta
, eta
), and otherwise returns zero. The function is
mainly intended to be used for testing purposes in the fmpz_lll
module.
fmpz_mat_is_reduced_gram
(const fmpz_mat_t A, double delta, double eta)¶Returns a nonzero value if the basis with Gram matrix A
is
LLLreduced with factor (delta
, eta
), and otherwise returns
zero. The function is mainly intended to be used for testing purposes in
the fmpz_lll
module.
fmpz_mat_is_reduced_with_removal
(const fmpz_mat_t A, double delta, double eta, const fmpz_t gs_B, int newd)¶Returns a nonzero value if the basis A
is LLLreduced with factor
(delta
, eta
) and the squared GramSchmidt length of each
\(i\)th vector (where \(i \ge\) newd
) is greater than gs_B
, and
otherwise returns zero. The function is mainly intended to be used for
testing purposes in the fmpz_lll
module.
fmpz_mat_lll_original
(fmpz_mat_t A, const fmpq_t delta, const fmpq_t eta)¶Takes a basis \(x_1, x_2, \ldots, x_m\) of the lattice \(L \subset R^n\) (as
the rows of a \(m \times n\) matrix A
). The output is an (delta
,
eta
)reduced basis \(y_1, y_2, \ldots, y_m\) of the lattice \(L\) (as
the rows of the same \(m \times n\) matrix A
).
fmpz_mat_lll_storjohann
(fmpz_mat_t A, const fmpq_t delta, const fmpq_t eta)¶Takes a basis \(x_1, x_2, \ldots, x_m\) of the lattice \(L \subset R^n\) (as
the rows of a \(m \times n\) matrix A
). The output is an (delta
,
eta
)reduced basis \(y_1, y_2, \ldots, y_m\) of the lattice \(L\) (as
the rows of the same \(m \times n\) matrix A
). Uses a modified version of
LLL, which has better complexity in terms of the lattice dimension,
introduced by Storjohann.
See “Faster Algorithms for Integer Lattice Basis Reduction.” Technical Report 249. Zurich, Switzerland: Department Informatik, ETH. July 30, 1996.