blockGLasso: Block Gibbs sampler for Bayesian Graphical Lasso

Description Usage Arguments Details Value Author(s) References Examples

Description

Blockwise sampling from the conditional distribution of a permuted column/row for simulating the posterior distribution for the concentration matrix specifying a Gaussian Graphical Model

Usage

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blockGLasso(X, iterations = 2000, burnIn = 1000, adaptive = FALSE,
  lambdaPriora = 1, lambdaPriorb = 1/10, adaptiveType = c("norm",
  "priorHyper"), priorHyper = NULL, gammaPriors = 1, gammaPriort = 1,
  lambdaii = 1, keepLambdas = TRUE, illStart = c("identity", "glasso"),
  rho = 0.1, verbose = TRUE, ...)

Arguments

X

Data matrix

iterations

Length of Markov chain after burn-in

burnIn

Number of burn-in iterations

adaptive

Logical; Adaptive graphical lasso (TRUE) or regular (FALSE). Default is FALSE.

lambdaPriora

Shrinkage parameter (lambda) gamma distribution shape hyperparameter (Ignored if adaptive=TRUE)

lambdaPriorb

Shrinkage parameter (lambda) gamma distribution scale hyperparameter (Ignored if adaptive=TRUE)

adaptiveType

Choose of adaptive type. Options are "norm" for norm of concentration matrix based adaptivity and "priorHyper" for informative adaptivity

priorHyper

Matrix of gamma scale hyper parameters (Ignord if adaptiveType="norm")

gammaPriors

labmda_ij gamma distribution shape prior (Ignored if adaptive=FALSE)

gammaPriort

lambda_ij gamma distribution rate prior (Ignored if adaptive=FALSE)

lambdaii

lambda_ii hyperparameter (Ignored if adaptive=FALSE)

keepLambdas

Logical: Should lambda MCMC chain (vector / matrix) be kept?

illStart

Method for generating a positive definite estimate of the sample covariance matrix if sample covariance matrix is not semi-positive definite

rho

Regularization parameter for the graphical lasso estimate of the sample covariance matrix (if illStart="glasso")

verbose

logical; if TRUE return MCMC progress

Details

Implements the block Gibbs sampler for the posterior distribution of a GGM concentration matrix estimated via the Bayesian Graphical Lasso introduced by Wang (2012) or the Bayesian Adaptive Graphical Lasso. For the adaptive case, the element-wise shrinkage parameter is drawn from a gamma distribution where the scale parameter is adaptively modulated directly from the estimated concentration matrix or a user can supply their own informative prior.

Value

Omega

List of concentration matrices from the Markov chains

Lambda

Vector of simulated lambda parameters

Author(s)

Patrick Trainor (University of Louisville)

Hao Wang

References

Wang, H. (2012). Bayesian graphical lasso models and efficient posterior computation. Bayesian Analysis, 7(4). <doi:10.1214/12-BA729> .

Examples

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# Generate true covariance matrix:
s<-.9**toeplitz(0:9)
# Generate multivariate normal distribution:
set.seed(5)
x<-MASS::mvrnorm(n=100,mu=rep(0,10),Sigma=s)
blockGLasso(X=x)

# Same example with short MCMC chain:
s<-.9**toeplitz(0:9)
set.seed(6)
x<-MASS::mvrnorm(n=100,mu=rep(0,10),Sigma=s)
blockGLasso(X=x,iterations=100,burnIn=100)

trainorp/BayesianGLasso documentation built on May 9, 2019, 12:51 p.m.