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dsp (version 1.2.0)

sampleDSP: Sample the dynamic shrinkage process parameters

Description

Compute one draw for each of the parameters in the dynamic shrinkage process for the special case in which the shrinkage parameter kappa ~ Beta(alpha, beta) with alpha = beta. The primary example is the dynamic horseshoe process with alpha = beta = 1/2.

Usage

sampleDSP(
  omega,
  evolParams,
  sigma_e = 1,
  loc = NULL,
  prior_dhs_phi = c(10, 2),
  alphaPlusBeta = 1
)

Value

List of relevant components:

  • the T x p evolution error standard deviations sigma_wt,

  • the T x p log-volatility ht, the p x 1 log-vol unconditional mean(s) dhs_mean,

  • the p x 1 log-vol AR(1) coefficient(s) dhs_phi,

  • the T x p log-vol innovation standard deviations sigma_eta_t from the Polya-Gamma priors,

  • the p x 1 initial log-vol SD sigma_eta_0,

  • and the mean of log-vol means dhs_mean0 (relevant when p > 1)

Arguments

omega

T x p matrix of evolution errors

evolParams

list of parameters to be updated (see Value below)

sigma_e

the observation error standard deviation; for (optional) scaling purposes

loc

list of the row and column indices to fill in a band-sparse matrix

prior_dhs_phi

the parameters of the prior for the log-volatility AR(1) coefficient dhs_phi; either NULL for uniform on [-1,1] or a 2-dimensional vector of (shape1, shape2) for a Beta prior on [(dhs_phi + 1)/2]

alphaPlusBeta

For the symmetric prior kappa ~ Beta(alpha, beta) with alpha=beta, specify the sum [alpha + beta]