Series
TensorDec.Series
— Type.Series{C,M}
Class representing multivariate series. The series is a dictionary, which associates values of type C to monomials of type M.
TensorDec.dual
— Function.dual(p::Polynomial, d:: Int64) -> Series{T}
Compute the series associated to the tensor p of degree d. T is the type of the coefficients of the polynomial p.
dual(p::Polynomial) -> Series{T}
Compute the series associated to the polynomial p, replacing the variables xi by its dual dxi. T is the type of the coefficients of the polynomial p.
dot
TensorDec.moment
— Function.moment(w::Vector{T}, P::Matrix{T}) -> Vector{Int64} -> T
Compute the moment function $α -> ∑_{i} ω_{i} P_{i}^α$ associated to the sequence P of r points of dimension n, which is a matrix of size r*n and the weights w.
moment(p::Polynomial, zeta::Vector{T}) -> Vector{Int64} -> T
Compute the moment function $α \rightarrow p(ζ^α)$.
TensorDec.series
— Function.series(f,L) -> Series{T}
Compute the generating series $\sum_{x^{α} \in L} f(α) z^α$ for a function $f: \mathbb{N}^n \rightarrow T$ and a sequence L of monomials.
series(w:: Vector{T}, P::Matrix{T}, L::Vector{M}) -> Series{T}
Compute the series of the moment sequence $∑_{i} ω_{i} P_{i}^α$ for $α \in L$.
series(w:: Vector{T}, P::Matrix{T}, X, d::Int64) -> Series{T}
Compute the series of the moment sequence $∑_i ω_{i} P_{i}^α$ for $|α| \leq d$.
series(p::Polynomial, zeta, X, d::Int64) -> Series{T}
Compute the series of moments $p(ζ^α)$ for $|α| \leq d$.
series(H::Matrix{C}, L1::Vector{M}, L2::Vector{M}) -> Series{C,M}
Compute the series associated to the Hankel matrix H, with rows (resp. columns) indexed by the array of monomials L1 (resp. L2).
TensorDec.hankel
— Function.hankel(σ::Series{T}, L1, L2) -> Array{T,2}
Hankel matrix of $σ$ with the rows indexed by the list of polynomials L1 and the columns by L2. The entries are the dot product for $σ$ of the corresponding elements in L1 and L2.
Example
julia> L =[1, x1, x2, x1^2, x1*x2, x2^2]
julia> H = hankel(s,L,L)
6x6 Array{Float64,2}:
4.0 5.0 7.0 5.0 11.0 13.0
5.0 5.0 11.0 -1.0 17.0 23.0
7.0 11.0 13.0 17.0 23.0 25.0
5.0 -1.0 17.0 -31.0 23.0 41.0
11.0 17.0 23.0 23.0 41.0 47.0
13.0 23.0 25.0 41.0 47.0 49.0
Compute the Hankel matrix (a.k.a. Catalecticant matrix) in degree d of the symmetric tensor F.
maxdegree