Matrices
Nemo allow the creation of dense matrices over any computable ring $R$. There are two different kinds of implementation: a generic one for the case where no specific implementation exists (provided by AbstractAlgebra.jl), and efficient implementations of matrices over numerous specific rings, usually provided by C/C++ libraries.
The following table shows each of the matrix types available in Nemo, the base ring $R$, and the Julia/Nemo types for that kind of matrix (the type information is mainly of concern to developers).
Base ring | Library | Element type | Parent type |
---|---|---|---|
Generic ring $R$ | AbstractAlgebra.jl | Generic.Mat{T} | Generic.MatSpace{T} |
$\mathbb{Z}$ | Flint | ZZMatrix | ZZMatrixSpace |
$\mathbb{Z}/n\mathbb{Z}$ (small $n$) | Flint | zzModMatrix | zzModMatrixSpace |
$\mathbb{Z}/n\mathbb{Z}$ (large $n$) | Flint | ZZModMatrix | ZZModMatrixSpace |
$\mathbb{Q}$ | Flint | QQMatrix | QQMatrixSpace |
$\mathbb{Z}/p\mathbb{Z}$ (small $p$) | Flint | fpMatrix | fpMatrixSpace |
$\mathbb{F}_{p^n}$ (small $p$) | Flint | fqPolyRepMatrix | fqPolyRepMatrixSpace |
$\mathbb{F}_{p^n}$ (large $p$) | Flint | FqPolyRepMatrix | FqPolyRepMatrixSpace |
$\mathbb{R}$ (arbitrary precision) | Arb | RealMatrix | RealMatrixSpace |
$\mathbb{C}$ (arbitrary precision) | Arb | ComplexMatrix | ComplexMatrixSpace |
$\mathbb{R}$ (fixed precision) | Arb | ArbMatrix | ArbMatrixSpace |
$\mathbb{C}$ (fixed precision) | Arb | AcbMatrix | AcbMatrixSpace |
The dimensions and base ring $R$ of a generic matrix are stored in its parent object.
All matrix element types belong to the abstract type MatElem
and all of the matrix space types belong to the abstract type MatSpace
. This enables one to write generic functions that can accept any Nemo matrix type.
Note that the preferred way to create matrices is not to use the type constructors but to use the matrix
function, see also the Matrix element constructors section of the AbstractAlgebra manual.
Matrix functionality
All matrix spaces in Nemo provide the matrix functionality of AbstractAlgebra:
https://nemocas.github.io/AbstractAlgebra.jl/stable/matrix
Some of this functionality is provided in Nemo by C libraries, such as Flint, for various specific rings.
In the following, we list the functionality which is provided in addition to the generic matrix functionality, for specific rings in Nemo.
Comparison operators
overlaps
— Methodoverlaps(x::RealMatrix, y::RealMatrix)
Returns true
if all entries of $x$ overlap with the corresponding entry of $y$, otherwise return false
.
overlaps
— Methodoverlaps(x::ComplexMatrix, y::ComplexMatrix)
Returns true
if all entries of $x$ overlap with the corresponding entry of $y$, otherwise return false
.
contains
— Methodcontains(x::RealMatrix, y::RealMatrix)
Returns true
if all entries of $x$ contain the corresponding entry of $y$, otherwise return false
.
contains
— Methodcontains(x::ComplexMatrix, y::ComplexMatrix)
Returns true
if all entries of $x$ contain the corresponding entry of $y$, otherwise return false
.
In addition we have the following ad hoc comparison operators.
Examples
julia> C = RR[1 2; 3 4]
[1.0000000000000000000 2.0000000000000000000]
[3.0000000000000000000 4.0000000000000000000]
julia> D = RR["1 +/- 0.1" "2 +/- 0.1"; "3 +/- 0.1" "4 +/- 0.1"]
[[1e+0 +/- 0.101] [2e+0 +/- 0.101]]
[[3e+0 +/- 0.101] [4e+0 +/- 0.101]]
julia> overlaps(C, D)
true
julia> contains(D, C)
true
Scaling
<<
— Method<<(x::ZZMatrix, y::Int)
Return $2^yx$.
>>
— Method>>(x::ZZMatrix, y::Int)
Return $x/2^y$ where rounding is towards zero.
Examples
julia> A = ZZ[2 3 5; 1 4 7; 9 6 3]
[2 3 5]
[1 4 7]
[9 6 3]
julia> B = A<<5
[ 64 96 160]
[ 32 128 224]
[288 192 96]
julia> C = B>>2
[16 24 40]
[ 8 32 56]
[72 48 24]
Determinant
det_divisor
— Methoddet_divisor(x::ZZMatrix)
Return some positive divisor of the determinant of $x$, if the determinant is nonzero, otherwise return zero.
det_given_divisor
— Methoddet_given_divisor(x::ZZMatrix, d::Integer, proved=true)
Return the determinant of $x$ given a positive divisor of its determinant. If proved == true
(the default), the output is guaranteed to be correct, otherwise a heuristic algorithm is used.
det_given_divisor
— Methoddet_given_divisor(x::ZZMatrix, d::ZZRingElem, proved=true)
Return the determinant of $x$ given a positive divisor of its determinant. If proved == true
(the default), the output is guaranteed to be correct, otherwise a heuristic algorithm is used.
Examples
julia> A = ZZ[2 3 5; 1 4 7; 9 6 3]
[2 3 5]
[1 4 7]
[9 6 3]
julia> c = det_divisor(A)
3
julia> d = det_given_divisor(A, c)
-30
Pseudo inverse
pseudo_inv
— Methodpseudo_inv(x::ZZMatrix)
Return a tuple $(z, d)$ consisting of a matrix $z$ and denominator $d$ such that $z/d$ is the inverse of $x$.
Examples
julia> A = ZZ[1 0 1; 2 3 1; 5 6 7]
[1 0 1]
[2 3 1]
[5 6 7]
julia> B, d = pseudo_inv(A)
([15 6 -3; -9 2 1; -3 -6 3], 12)
Nullspace
nullspace_right_rational
— Methodnullspace_right_rational(x::ZZMatrix)
Return a tuple $(r, U)$ consisting of a matrix $U$ such that the first $r$ columns form the right rational nullspace of $x$, i.e. a set of vectors over $\mathbb{Z}$ giving a $\mathbb{Q}$-basis for the nullspace of $x$ considered as a matrix over $\mathbb{Q}$.
Modular reduction
reduce_mod
— Methodreduce_mod(x::ZZMatrix, y::Integer)
Reduce the entries of $x$ modulo $y$ and return the result.
reduce_mod
— Methodreduce_mod(x::ZZMatrix, y::ZZRingElem)
Reduce the entries of $x$ modulo $y$ and return the result.
Examples
julia> A = ZZ[2 3 5; 1 4 7; 9 2 2]
[2 3 5]
[1 4 7]
[9 2 2]
julia> reduce_mod(A, ZZ(5))
[2 3 0]
[1 4 2]
[4 2 2]
julia> reduce_mod(A, 2)
[0 1 1]
[1 0 1]
[1 0 0]
Lifting
lift
— Methodlift(a::T) where {T <: Zmodn_mat}
Return a lift of the matrix $a$ to a matrix over $\mathbb{Z}$, i.e. where the entries of the returned matrix are those of $a$ lifted to $\mathbb{Z}$.
lift(M::smodule{T}, SM::smodule{T}) where T
Represents the generators of SM
in terms of the generators of M
. If SM
is in M
, rest
is the null module, otherwise rest = reduce(SM, std(M))
. Returns (result, rest)
with for global orderings: Matrix(SM) - Matrix(rest) = Matrix(M)*Matrix(result)
for non-global orderings: Matrix(SM)*U - Matrix(rest) = Matrix(M)*Matrix(result)
where U
is some diagonal matrix of units. To compute this U
, see lift(M::smodule, SM::smodule, goodShape::Bool, isSB::Bool, divide::Bool)
.
lift(M::smodule{T}, SM::smodule{T}, goodShape::Bool, isSB::Bool, divide::Bool) where T
Represents the generators of SM
in terms of the generators of M
. Returns (result, rest, U)
with Matrix(SM)*U - Matrix(rest) = Matrix(M)*Matrix(result)
If SM
is in M
, then rest
is the null module. Otherwise, rest = SM
if !divide
, and rest = normalform(SM, std(M))
if divide
. U
is a diagonal matrix of units, differing from the identity matrix only for local ring orderings.
There are three boolean options. goodShape
: maximal non-zero index in generators of SM
<= that of M
, which should be come from a rank check rank(SM)==rank(M)
. isSB
: generators of M
form a Groebner basis. divide
: allow SM
not to be a submodule of M
.
lift(M::sideal{T}, SM::sideal{T}) where T
Represents the generators of SM
in terms of the generators of M
. If SM
is in M
, rest
is the null module, otherwise rest = reduce(SM, std(M))
. Returns (result, rest)
with for global orderings: Matrix(SM) - Matrix(rest) = Matrix(M)*Matrix(result)
for non-global orderings: Matrix(SM)*U - Matrix(rest) = Matrix(M)*Matrix(result)
where U
is some diagonal matrix of units. To compute this U
, see lift(M::sideal, SM::sideal, goodShape::Bool, isSB::Bool, divide::Bool)
.
lift(M::sideal{T}, SM::sideal{T}, goodShape::Bool, isSB::Bool, divide::Bool) where T
Represents the generators of SM
in terms of the generators of M
. Returns (result, rest, U)
with Matrix(SM)*U - Matrix(rest) = Matrix(M)*Matrix(result)
If SM
is in M
, then rest
is the null module. Otherwise, rest = SM
if !divide
, and rest = normalform(SM, std(M))
if divide
. U
is a diagonal matrix of units, differing from the identity matrix only for local ring orderings.
There are three boolean options. goodShape
: maximal non-zero index in generators of SM
<= that of M
, which should be come from a rank check rank(SM)==rank(M)
. isSB
: generators of M
form a Groebner basis divide
: allow SM
not to be a submodule of M
, which is useful for division with remainder.
lift
— Methodlift(a::T) where {T <: Zmodn_mat}
Return a lift of the matrix $a$ to a matrix over $\mathbb{Z}$, i.e. where the entries of the returned matrix are those of $a$ lifted to $\mathbb{Z}$.
lift(M::smodule{T}, SM::smodule{T}) where T
Represents the generators of SM
in terms of the generators of M
. If SM
is in M
, rest
is the null module, otherwise rest = reduce(SM, std(M))
. Returns (result, rest)
with for global orderings: Matrix(SM) - Matrix(rest) = Matrix(M)*Matrix(result)
for non-global orderings: Matrix(SM)*U - Matrix(rest) = Matrix(M)*Matrix(result)
where U
is some diagonal matrix of units. To compute this U
, see lift(M::smodule, SM::smodule, goodShape::Bool, isSB::Bool, divide::Bool)
.
lift(M::smodule{T}, SM::smodule{T}, goodShape::Bool, isSB::Bool, divide::Bool) where T
Represents the generators of SM
in terms of the generators of M
. Returns (result, rest, U)
with Matrix(SM)*U - Matrix(rest) = Matrix(M)*Matrix(result)
If SM
is in M
, then rest
is the null module. Otherwise, rest = SM
if !divide
, and rest = normalform(SM, std(M))
if divide
. U
is a diagonal matrix of units, differing from the identity matrix only for local ring orderings.
There are three boolean options. goodShape
: maximal non-zero index in generators of SM
<= that of M
, which should be come from a rank check rank(SM)==rank(M)
. isSB
: generators of M
form a Groebner basis. divide
: allow SM
not to be a submodule of M
.
lift(M::sideal{T}, SM::sideal{T}) where T
Represents the generators of SM
in terms of the generators of M
. If SM
is in M
, rest
is the null module, otherwise rest = reduce(SM, std(M))
. Returns (result, rest)
with for global orderings: Matrix(SM) - Matrix(rest) = Matrix(M)*Matrix(result)
for non-global orderings: Matrix(SM)*U - Matrix(rest) = Matrix(M)*Matrix(result)
where U
is some diagonal matrix of units. To compute this U
, see lift(M::sideal, SM::sideal, goodShape::Bool, isSB::Bool, divide::Bool)
.
lift(M::sideal{T}, SM::sideal{T}, goodShape::Bool, isSB::Bool, divide::Bool) where T
Represents the generators of SM
in terms of the generators of M
. Returns (result, rest, U)
with Matrix(SM)*U - Matrix(rest) = Matrix(M)*Matrix(result)
If SM
is in M
, then rest
is the null module. Otherwise, rest = SM
if !divide
, and rest = normalform(SM, std(M))
if divide
. U
is a diagonal matrix of units, differing from the identity matrix only for local ring orderings.
There are three boolean options. goodShape
: maximal non-zero index in generators of SM
<= that of M
, which should be come from a rank check rank(SM)==rank(M)
. isSB
: generators of M
form a Groebner basis divide
: allow SM
not to be a submodule of M
, which is useful for division with remainder.
Examples
julia> R, = residue_ring(ZZ, 7)
(Integers modulo 7, Map: ZZ -> ZZ/(7))
julia> a = R[4 5 6; 7 3 2; 1 4 5]
[4 5 6]
[0 3 2]
[1 4 5]
julia> b = lift(a)
[-3 -2 -1]
[ 0 3 2]
[ 1 -3 -2]
Special matrices
hadamard
— Methodhadamard(R::ZZMatrixSpace)
Return the Hadamard matrix for the given matrix space. The number of rows and columns must be equal.
is_hadamard
— Methodis_hadamard(x::ZZMatrix)
Return true
if the given matrix is Hadamard, otherwise return false
.
hilbert
— Methodhilbert(R::QQMatrixSpace)
Return the Hilbert matrix in the given matrix space. This is the matrix with entries $H_{i,j} = 1/(i + j - 1)$.
Examples
julia> hadamard(matrix_space(ZZ, 3, 3))
ERROR: Unable to create Hadamard matrix
[...]
julia> A = hadamard(matrix_space(ZZ, 4, 4))
[1 1 1 1]
[1 -1 1 -1]
[1 1 -1 -1]
[1 -1 -1 1]
julia> is_hadamard(A)
true
julia> B = hilbert(matrix_space(QQ, 3, 3))
[ 1 1//2 1//3]
[1//2 1//3 1//4]
[1//3 1//4 1//5]
Hermite Normal Form
hnf
— Methodhnf(x::ZZMatrix)
Return the Hermite Normal Form of $x$.
hnf_with_transform
— Methodhnf_with_transform(x::ZZMatrix)
Compute a tuple $(H, T)$ where $H$ is the Hermite normal form of $x$ and $T$ is a transformation matrix so that $H = Tx$.
hnf_modular
— Methodhnf_modular(x::ZZMatrix, d::ZZRingElem)
Compute the Hermite normal form of $x$ given that $d$ is a multiple of the determinant of the nonzero rows of $x$.
hnf_modular_eldiv
— Methodhnf_modular_eldiv(x::ZZMatrix, d::ZZRingElem)
Compute the Hermite normal form of $x$ given that $d$ is a multiple of the largest elementary divisor of $x$. The matrix $x$ must have full rank.
is_hnf
— Methodis_hnf(x::ZZMatrix)
Return true
if the given matrix is in Hermite Normal Form, otherwise return false
.
Examples
julia> A = ZZ[2 3 5; 1 4 7; 19 3 7]
[ 2 3 5]
[ 1 4 7]
[19 3 7]
julia> B = hnf(A)
[1 0 16]
[0 1 18]
[0 0 27]
julia> H, T = hnf_with_transform(A)
([1 0 16; 0 1 18; 0 0 27], [-43 30 3; -44 31 3; -73 51 5])
julia> M = hnf_modular(A, ZZ(27))
[1 0 16]
[0 1 18]
[0 0 27]
julia> N = hnf_modular_eldiv(A, ZZ(27))
[1 0 16]
[0 1 18]
[0 0 27]
julia> is_hnf(M)
true
Lattice basis reduction
Nemo provides LLL lattice basis reduction. Optionally one can specify the setup using a context object created by the following function.
LLLContext(delta::Float64, eta::Float64, rep=:zbasis, gram=:approx)
Return a LLL context object specifying LLL parameters $\delta$ and $\eta$ and specifying the representation as either :zbasis
or :gram
and the Gram type as either :approx
or :exact
.
lll
— Methodlll(x::ZZMatrix, ctx::LLLContext = LLLContext(0.99, 0.51))
Return a matrix $L$ whose rows form an LLL-reduced basis of the $\mathbb{Z}$-lattice generated by the rows of $x$. $L$ may contain additional zero rows.
By default, the LLL is performed with reduction parameters $\delta = 0.99$ and $\eta = 0.51$. These defaults can be overridden by specifying an optional context object.
See lll_gram
for a function taking the Gram matrix as input.
lll_with_transform
— Methodlll_with_transform(x::ZZMatrix, ctx::LLLContext = LLLContext(0.99, 0.51))
Return a tuple $(L, T)$ where the rows of $L$ form an LLL-reduced basis of the $\mathbb{Z}$-lattice generated by the rows of $x$ and $T$ is a transformation matrix so that $L = Tx$. $L$ may contain additional zero rows. See lll
for the used default parameters which can be overridden by supplying an optional context object.
See lll_gram_with_transform
for a function taking the Gram matrix as input.
lll_gram
— Methodlll_gram(x::ZZMatrix, ctx::LLLContext = LLLContext(0.99, 0.51, :gram))
Return the Gram matrix $L$ of an LLL-reduced basis of the lattice given by the Gram matrix $x$. The matrix $x$ must be symmetric and non-singular.
By default, the LLL is performed with reduction parameters $\delta = 0.99$ and $\eta = 0.51$. These defaults can be overridden by specifying an optional context object.
lll_gram_with_transform
— Methodlll_gram_with_transform(x::ZZMatrix, ctx::LLLContext = LLLContext(0.99, 0.51, :gram))
Return a tuple $(L, T)$ where $L$ is the Gram matrix of an LLL-reduced basis of the lattice given by the Gram matrix $x$ and $T$ is a transformation matrix with $L = T^\top x T$. The matrix $x$ must be symmetric and non-singular.
See lll_gram
for the used default parameters which can be overridden by supplying an optional context object.
lll_with_removal
— Methodlll_with_removal(x::ZZMatrix, b::ZZRingElem, ctx::LLLContext = LLLContext(0.99, 0.51))
Compute the LLL reduction of $x$ and throw away rows whose norm exceeds the given bound $b$. Return a tuple $(r, L)$ where the first $r$ rows of $L$ are the rows remaining after removal.
lll_with_removal_transform
— Methodlll_with_removal_transform(x::ZZMatrix, b::ZZRingElem, ctx::LLLContext = LLLContext(0.99, 0.51))
Compute a tuple $(r, L, T)$ where the first $r$ rows of $L$ are those remaining from the LLL reduction after removal of vectors with norm exceeding the bound $b$ and $T$ is a transformation matrix so that $L = Tx$.
lll!
— Methodlll!(x::ZZMatrix, ctx::LLLContext = LLLContext(0.99, 0.51))
Compute an LLL-reduced basis of the $\mathbb{Z}$-lattice generated by the rows of $x$ inplace.
By default, the LLL is performed with reduction parameters $\delta = 0.99$ and $\eta = 0.51$. These defaults can be overridden by specifying an optional context object.
See lll_gram!
for a function taking the Gram matrix as input.
lll_gram!
— Methodlll_gram!(x::ZZMatrix, ctx::LLLContext = LLLContext(0.99, 0.51, :gram))
Compute the Gram matrix of an LLL-reduced basis of the lattice given by the Gram matrix $x$ inplace. The matrix $x$ must be symmetric and non-singular.
By default, the LLL is performed with reduction parameters $\delta = 0.99$ and $\eta = 0.51$. These defaults can be overridden by specifying an optional context object.
Examples
julia> A = ZZ[2 3 5; 1 4 7; 19 3 7]
[ 2 3 5]
[ 1 4 7]
[19 3 7]
julia> L = lll(A, LLLContext(0.95, 0.55, :zbasis, :approx))
[-1 1 2]
[-1 -2 2]
[ 4 1 1]
julia> L, T = lll_with_transform(A)
([-1 1 2; -1 -2 2; 4 1 1], [-1 1 0; -15 10 1; 3 -2 0])
julia> G = lll_gram(gram(A))
[ 6 3 -1]
[ 3 9 -4]
[-1 -4 18]
julia> G, T = lll_gram_with_transform(gram(A))
([6 3 -1; 3 9 -4; -1 -4 18], [-1 1 0; -15 10 1; 3 -2 0])
julia> r, L = lll_with_removal(A, ZZ(100))
(3, [-1 1 2; -1 -2 2; 4 1 1])
julia> r, L, T = lll_with_removal_transform(A, ZZ(100))
(3, [-1 1 2; -1 -2 2; 4 1 1], [-1 1 0; -15 10 1; 3 -2 0])
Smith Normal Form
snf
— Methodsnf(x::ZZMatrix)
Compute the Smith normal form of $x$.
snf_diagonal
— Methodsnf_diagonal(x::ZZMatrix)
Given a diagonal matrix $x$ compute the Smith normal form of $x$.
is_snf
— Methodis_snf(x::ZZMatrix)
Return true
if $x$ is in Smith normal form, otherwise return false
.
Examples
julia> A = ZZ[2 3 5; 1 4 7; 19 3 7]
[ 2 3 5]
[ 1 4 7]
[19 3 7]
julia> B = snf(A)
[1 0 0]
[0 1 0]
[0 0 27]
julia> is_snf(B) == true
true
julia> B = ZZ[2 0 0; 0 4 0; 0 0 7]
[2 0 0]
[0 4 0]
[0 0 7]
julia> C = snf_diagonal(B)
[1 0 0]
[0 2 0]
[0 0 28]
Strong Echelon Form
strong_echelon_form
— Methodstrong_echelon_form(a::zzModMatrix)
Return the strong echeleon form of $a$. The matrix $a$ must have at least as many rows as columns.
strong_echelon_form
— Methodstrong_echelon_form(a::fpMatrix)
Return the strong echeleon form of $a$. The matrix $a$ must have at least as many rows as columns.
Examples
julia> R, = residue_ring(ZZ, 12);
julia> A = R[4 1 0; 0 0 5; 0 0 0 ]
[4 1 0]
[0 0 5]
[0 0 0]
julia> B = strong_echelon_form(A)
[4 1 0]
[0 3 0]
[0 0 1]
Howell Form
howell_form
— Methodhowell_form(a::zzModMatrix)
Return the Howell normal form of $a$. The matrix $a$ must have at least as many rows as columns.
howell_form
— Methodhowell_form(a::fpMatrix)
Return the Howell normal form of $a$. The matrix $a$ must have at least as many rows as columns.
Examples
julia> R, = residue_ring(ZZ, 12);
julia> A = R[4 1 0; 0 0 5; 0 0 0 ]
[4 1 0]
[0 0 5]
[0 0 0]
julia> B = howell_form(A)
[4 1 0]
[0 3 0]
[0 0 1]
Gram-Schmidt Orthogonalisation
gram_schmidt_orthogonalisation
— Methodgram_schmidt_orthogonalisation(x::QQMatrix)
Takes the columns of $x$ as the generators of a subset of $\mathbb{Q}^m$ and returns a matrix whose columns are an orthogonal generating set for the same subspace.
Examples
julia> S = matrix_space(QQ, 3, 3);
julia> A = S([4 7 3; 2 9 1; 0 5 3])
[4 7 3]
[2 9 1]
[0 5 3]
julia> B = gram_schmidt_orthogonalisation(A)
[4 -11//5 95//123]
[2 22//5 -190//123]
[0 5 209//123]
Exponential
Examples
julia> A = RR[2 0 0; 0 3 0; 0 0 1]
[2.0000000000000000000 0 0]
[ 0 3.0000000000000000000 0]
[ 0 0 1.0000000000000000000]
julia> B = exp(A)
[[7.389056098930650227 +/- 4.72e-19] 0 0]
[ 0 [20.08553692318766774 +/- 1.94e-18] 0]
[ 0 0 [2.718281828459045235 +/- 4.30e-19]]
Norm
bound_inf_norm
— Methodbound_inf_norm(x::RealMatrix)
Returns a non-negative element $z$ of type ArbFieldElem
, such that $z$ is an upper bound for the infinity norm for every matrix in $x$
bound_inf_norm
— Methodbound_inf_norm(x::ComplexMatrix)
Returns a non-negative element $z$ of type AcbFieldElem
, such that $z$ is an upper bound for the infinity norm for every matrix in $x$
Examples
julia> A = RR[1 2 3; 4 5 6; 7 8 9]
[1.0000000000000000000 2.0000000000000000000 3.0000000000000000000]
[4.0000000000000000000 5.0000000000000000000 6.0000000000000000000]
[7.0000000000000000000 8.0000000000000000000 9.0000000000000000000]
julia> d = bound_inf_norm(A)
[24.000000059604644775 +/- 3.91e-19]
Shifting
Examples
julia> A = RR[1 2 3; 4 5 6; 7 8 9]
[1.0000000000000000000 2.0000000000000000000 3.0000000000000000000]
[4.0000000000000000000 5.0000000000000000000 6.0000000000000000000]
[7.0000000000000000000 8.0000000000000000000 9.0000000000000000000]
julia> B = ldexp(A, 4)
[16.000000000000000000 32.000000000000000000 48.000000000000000000]
[64.000000000000000000 80.000000000000000000 96.000000000000000000]
[112.00000000000000000 128.00000000000000000 144.00000000000000000]
julia> overlaps(16*A, B)
true
Predicates
Examples
julia> A = CC[1 2 3; 4 5 6; 7 8 9]
[1.0000000000000000000 2.0000000000000000000 3.0000000000000000000]
[4.0000000000000000000 5.0000000000000000000 6.0000000000000000000]
[7.0000000000000000000 8.0000000000000000000 9.0000000000000000000]
julia> isreal(A)
true
julia> isreal(onei(CC)*A)
false
Conversion to Julia matrices
Julia matrices use a different data structure than Nemo matrices. Conversion to Julia matrices is usually only required for interfacing with other packages. It isn't necessary to convert Nemo matrices to Julia matrices in order to manipulate them.
This conversion can be performed with standard Julia syntax, such as the following, where A
is an ZZMatrix
:
Matrix{Int}(A)
Matrix{BigInt}(A)
In case the matrix cannot be converted without loss, an InexactError
is thrown: in this case, cast to a matrix of BigInt
s rather than Int
s.
Eigenvalues and Eigenvectors (experimental)
eigenvalues
— Methodeigenvalues(A::ComplexMatrix)
Return the eigenvalues of A
.
This function is experimental.
eigenvalues_with_multiplicities
— Methodeigenvalues_with_multiplicities(A::ComplexMatrix)
Return the eigenvalues of A
with their algebraic multiplicities as a vector of tuples (ComplexFieldElem, Int)
. Each tuple (z, k)
corresponds to a cluster of k
eigenvalues of $A$.
This function is experimental.
eigenvalues_simple
— Methodeigenvalues_simple(A::ComplexMatrix, algorithm::Symbol = :default)
Returns the eigenvalues of A
as a vector of AcbFieldElem
. It is assumed that A
has only simple eigenvalues.
The algorithm used can be changed by setting the algorithm
keyword to :vdhoeven_mourrain
or :rump
.
This function is experimental.
julia> A = CC[1 2 3; 0 4 5; 0 0 6]
[1.0000000000000000000 2.0000000000000000000 3.0000000000000000000]
[ 0 4.0000000000000000000 5.0000000000000000000]
[ 0 0 6.0000000000000000000]
julia> eigenvalues_simple(A)
3-element Vector{ComplexFieldElem}:
1.0000000000000000000
4.0000000000000000000
6.0000000000000000000
julia> A = CC[2 2 3; 0 2 5; 0 0 2]
[2.0000000000000000000 2.0000000000000000000 3.0000000000000000000]
[ 0 2.0000000000000000000 5.0000000000000000000]
[ 0 0 2.0000000000000000000]
julia> eigenvalues(A)
1-element Vector{ComplexFieldElem}:
2.0000000000000000000
julia> eigenvalues_with_multiplicities(A)
1-element Vector{Tuple{ComplexFieldElem, Int64}}:
(2.0000000000000000000, 3)