Learn R Programming

gmvarkit (version 1.1.1)

pick_allA: Pick coefficient all matrices

Description

pick_allA picks all coefficient matrices \(A_{m,i} (i=1,..,p, m=1,..,M)\) from the given parameter vector so that they are arranged in a 4D array with the fourth dimension indicating each component and third dimension indicating each lag.

Usage

pick_allA(p, M, d, params)

Arguments

p

a positive integer specifying the autoregressive order of the model.

M

a positive integer specifying the number of mixture components.

d

number of time series in the system.

params

a real valued vector specifying the parameter values. Should be size \(((M(pd^2+d+d(d+1)/2+1)-1)x1)\) and have form \(\theta\)\( = \)(\(\upsilon\)\(_{1}\), ...,\(\upsilon\)\(_{M}\), \(\alpha_{1},...,\alpha_{M-1}\)), where:

  • \(\upsilon\)\(_{m}\) \( = (\phi_{m,0},\)\(\phi\)\(_{m}\)\(,\sigma_{m})\)

  • \(\phi\)\(_{m}\)\( = (vec(A_{m,1}),...,vec(A_{m,p})\)

  • and \(\sigma_{m} = vech(\Omega_{m})\), m=1,...,M.

Above \(\phi_{m,0}\) is the intercept parameter, \(A_{m,i}\) denotes the \(i\):th coefficient matrix of the \(m\):th mixture component, \(\Omega_{m}\) denotes the error term covariance matrix of the \(m\):th mixture component and \(\alpha_{m}\) is the mixing weight parameter. If parametrization=="mean", just replace each \(\phi_{m,0}\) with regimewise mean \(\mu_{m}\). \(vec()\) is vectorization operator that stacks columns of a given matrix into a vector. \(vech()\) stacks columns of a given matrix from the principal diagonal downwards (including elements on the diagonal) into a vector. The notations are in line with the cited article by KMS (2016).

Value

Returns a 4D array containing the coefficient matrices of the all components. Coefficient matrix \(A_{m,i}\) can be obtained by choosing [, , i, m].

Warning

No argument checks!

References

  • Kalliovirta L., Meitz M. and Saikkonen P. 2016. Gaussian mixture vector autoregression. Journal of Econometrics, 192, 485-498.

  • Lutkepohl H. 2005. New Introduction to Multiple Time Series Analysis, Springer.