#' Bayesian LASSO
#'
#' @description The Bayesian LASSO of Park & Casella (2008). The Bayesian Lasso is equivalent to using independent double exponential
#' (Laplace distribution) priors on the
#' coefficients with a scale of sigma / lambda. However, doing this directly results in slow convergence and poor mixing.
#' The Laplace distribution can be expressed as a scale mixture of normals with an exponential distribution as the scale
#' parameter. This is the method that Park & Casella (2008) utilize and the method that is utilized here. The hierarchical
#' structure of the prior distribution is given below. \cr
#' \cr
#' Note that for the binomial and poisson likelihood functions plug-in pseudovariances are used.
#' \cr
#' Model Specification:
#' \cr
#' \if{html}{\figure{blasso.png}{}}
#' \if{latex}{\figure{blasso.png}{}}
#' \cr
#' \cr
#' Plugin Pseudo-Variances: \cr
#' \cr
#' \if{html}{\figure{pseudovar.png}{}}
#' \if{latex}{\figure{pseudovar.png}{}}
#'
#'
#' @param formula the model formula
#' @param data a data frame.
#' @param family one of "gaussian", "st" (Student-t with nu=3), "binomial", or "poisson".
#' @param lambda.prior either "dmouch" (the default) or "gamma"
#' @param log_lik Should the log likelihood be monitored? The default is FALSE.
#' @param iter How many post-warmup samples? Defaults to 10000.
#' @param warmup How many warmup samples? Defaults to 1000.
#' @param adapt How many adaptation steps? Defaults to 2000.
#' @param chains How many chains? Defaults to 4.
#' @param thin Thinning interval. Defaults to 1.
#' @param method Defaults to "rjparallel". For an alternative parallel option, choose "parallel" or. Otherwise, "rjags" (single core run).
#' @param cl Use parallel::makeCluster(# clusters) to specify clusters for the parallel methods. Defaults to two cores.
#' @param ... Other arguments to run.jags.
#'
#' @references Park, T., & Casella, G. (2008). The Bayesian Lasso. Journal of the American Statistical Association, 103(482), 681-686. Retrieved from http://www.jstor.org/stable/27640090 \cr
#' \cr
#' @return
#' a runjags object
#' @export
#' @examples
#' blasso()
blasso = function(formula, data, family = "gaussian", lambda.prior = "dmouch", log_lik = FALSE, iter=10000, warmup=1000, adapt=2000, chains=4, thin=1, method = "rjparallel", cl = makeCluster(2), ...){
X = model.matrix(formula, data)[,-1]
y = model.frame(formula, data)[,1]
if (lambda.prior == "dmouch") {
if (method == "parallel"){
message("method switching to rjparallel to enable use of DuMouchel's prior")
method <- "rjparallel"
}
if (family == "gaussian"){
resids = y - as.vector(lmSolve(formula , data) %*% t(model.matrix(formula, data)))
tau = prec(resids)
jags_blasso = "model{
lambda ~ dmouch(1)
tau ~ dgamma(0.01, 0.01)
sigma2 <- 1 / tau
for (p in 1:P){
eta[p] ~ dexp(lambda^2 / 2)
omega[p] <- 1 / (sigma2 * eta[p])
beta[p] ~ dnorm(0, omega[p])
}
Intercept ~ dnorm(0, 1e-10)
for (i in 1:N){
mu[i] <- Intercept + sum(beta[1:P] * X[i,1:P])
y[i] ~ dnorm(mu[i], tau)
log_lik[i] <- logdensity.norm(y[i], mu[i], tau)
ySim[i] ~ dnorm(mu[i], tau)
}
sigma <- sqrt(sigma2)
Deviance <- -2 * sum(log_lik[1:N])
}"
P <- ncol(X)
write_lines(jags_blasso, "jags_blasso.txt")
jagsdata <- list(X = X, y = y, N = length(y), P = ncol(X))
monitor <- c("Intercept", "beta", "sigma", "lambda", "Deviance", "ySim", "log_lik")
if (log_lik == FALSE){
monitor = monitor[-(length(monitor))]
}
inits <- lapply(1:chains, function(z) list("Intercept" = lmSolve(formula, data)[1],
"beta" = lmSolve(formula, data)[-1],
"eta" = rep(1, P),
"tau" = tau,
"lambda" = sample(2:10, size = 1),
"ySim" = sample(y, length(y)),
.RNG.name= "lecuyer::RngStream",
.RNG.seed= sample(1:10000, 1)))
out = run.jags(model = "jags_blasso.txt", modules = c("bugs on", "glm on", "dic off"), n.chains = chains, monitor = monitor, data = jagsdata, inits = inits, burnin = warmup, sample = iter, thin = thin, adapt = adapt, method = method, cl = cl, summarise = FALSE, ...)
file.remove("jags_blasso.txt")
if (!is.null(cl)) {
parallel::stopCluster(cl = cl)
}
return(out)
}
if (family == "st"){
resids = y - as.vector(lmSolve(formula , data) %*% t(model.matrix(formula, data)))
tau = prec(resids)
jags_blasso = "model{
tau ~ dgamma(.01, .01)
sigma2 <- 1/tau
lambda ~ dmouch(1)
for (p in 1:P){
eta[p] ~ dexp(lambda^2 / 2)
omega[p] <- 1 / (sigma2 * eta[p])
beta[p] ~ dnorm(0, omega[p])
}
Intercept ~ dnorm(0, 1e-5)
for (i in 1:N){
mu[i] <- Intercept + sum(beta[1:P] * X[i,1:P])
y[i] ~ dt(mu[i], tau, 3)
log_lik[i] <- logdensity.t(y[i], mu[i], tau, 3)
ySim[i] ~ dt(mu[i], tau, 3)
}
sigma <- sqrt(sigma2)
Deviance <- -2 * sum(log_lik[1:N])
}"
P <- ncol(X)
write_lines(jags_blasso, "jags_blasso.txt")
jagsdata <- list(X = X, y = y, N = length(y), P = ncol(X))
monitor <- c("Intercept", "beta", "sigma", "lambda", "Deviance", "ySim", "log_lik")
if (log_lik == FALSE){
monitor = monitor[-(length(monitor))]
}
inits <- lapply(1:chains, function(z) list("Intercept" = lmSolve(formula, data)[1],
"beta" = lmSolve(formula, data)[-1],
"eta" = rep(1, P),
"tau" = tau * 3,
"lambda" = sample(2:10, size = 1),
"ySim" = sample(y, length(y)),
.RNG.name= "lecuyer::RngStream",
.RNG.seed= sample(1:10000, 1)))
out = run.jags(model = "jags_blasso.txt", modules = c("bugs on", "glm on", "dic off"), monitor = monitor, data = jagsdata, inits = inits, burnin = warmup, sample = iter, thin = thin, adapt = adapt, method = method, cl = cl, n.chains = chains, summarise = FALSE, ...)
file.remove("jags_blasso.txt")
if (!is.null(cl)) {
parallel::stopCluster(cl = cl)
}
return(out)
}
if (family == "binomial"){
jags_blasso = "model{
lambda ~ dgamma(0.50, 0.20)
for (p in 1:P){
eta[p] ~ dexp(lambda^2 / 2)
omega[p] <- 1 / (sigma2 * eta[p])
beta[p] ~ dnorm(0, omega[p])
}
Intercept ~ dnorm(0, 1e-10)
for (i in 1:N){
logit(psi[i]) <- Intercept + sum(beta[1:P] * X[i,1:P])
y[i] ~ dbern(psi[i])
log_lik[i] <- logdensity.bern(y[i], psi[i])
ySim[i] ~ dbern(psi[i])
}
Deviance <- -2 * sum(log_lik[1:N])
}"
P <- ncol(X)
write_lines(jags_blasso, "jags_blasso.txt")
jagsdata <- list(X = X, y = y, N = length(y), P = ncol(X), sigma2 = pow(mean(y), -1) * pow(1 - mean(y), -1))
monitor <- c("Intercept", "beta", "lambda", "Deviance", "ySim", "log_lik")
if (log_lik == FALSE){
monitor = monitor[-(length(monitor))]
}
inits <- lapply(1:chains, function(z) list("Intercept" = as.vector(coef(glmnet::glmnet(x = X, y = y, family = "binomial", lambda = 0.025, alpha = 0, standardize = FALSE))[1,1]),
"beta" = rep(0, P),
"eta" = rgamma(P, 2, 1),
"lambda" = sample(2:10, size = 1),
"ySim" = sample(y, length(y)),
.RNG.name= "lecuyer::RngStream",
.RNG.seed= sample(1:10000, 1)))
out = run.jags(model = "jags_blasso.txt", modules = c("bugs on", "glm on", "dic off"), monitor = monitor, data = jagsdata, inits = inits, burnin = warmup, sample = iter, thin = thin, adapt = adapt, method = method, cl = cl, summarise = FALSE, ...)
file.remove("jags_blasso.txt")
if (!is.null(cl)) {
parallel::stopCluster(cl = cl)
}
return(out)
}
if (family == "poisson"){
jags_blasso = "model{
lambda ~ dgamma(0.5 , 0.20)
for (p in 1:P){
eta[p] ~ dexp(lambda^2 / 2)
omega[p] <- 1 / (sigma2 * eta[p])
beta[p] ~ dnorm(0, omega[p])
}
Intercept ~ dnorm(0, 1e-10)
for (i in 1:N){
log(psi[i]) <- Intercept + sum(beta[1:P] * X[i,1:P])
y[i] ~ dpois(psi[i])
log_lik[i] <- logdensity.pois(y[i], psi[i])
ySim[i] ~ dpois(psi[i])
}
Deviance <- -2 * sum(log_lik[1:N])
}"
P <- ncol(X)
write_lines(jags_blasso, "jags_blasso.txt")
jagsdata <- list(X = X, y = y, N = length(y), P = ncol(X), sigma2 = pow(mean(y) , -1))
monitor <- c("Intercept", "beta", "lambda", "Deviance", "ySim", "log_lik")
if (log_lik == FALSE){
monitor = monitor[-(length(monitor))]
}
inits <- lapply(1:chains, function(z) list("Intercept" = as.vector(coef(glmnet::glmnet(x = X, y = y, family = "poisson", lambda = 0.025, alpha = 0, standardize = FALSE))[1,1]),
"beta" = rep(0, P),
"eta" = rgamma(P, 2, 1),
"lambda" = sample(2:10, size = 1),
"ySim" = sample(y, length(y)),
.RNG.name= "lecuyer::RngStream",
.RNG.seed= sample(1:10000, 1)))
out = run.jags(model = "jags_blasso.txt", modules = c("bugs on", "glm on", "dic off"), n.chains = chains, monitor = monitor, data = jagsdata, inits = inits, burnin = warmup, sample = iter, thin = thin, adapt = adapt, method = method, cl = cl, summarise = FALSE, ...)
file.remove("jags_blasso.txt")
if (!is.null(cl)) {
parallel::stopCluster(cl = cl)
}
return(out)
}
}
if (lambda.prior == "gamma"){
if (family == "gaussian"){
resids = y - as.vector(lmSolve(formula , data) %*% t(model.matrix(formula, data)))
tau = prec(resids)
jags_blasso = "model{
lambda ~ dgamma(0.50, 0.20)
tau ~ dgamma(0.01, 0.01)
sigma2 <- 1 / tau
for (p in 1:P){
eta[p] ~ dexp(lambda^2 / 2)
omega[p] <- 1 / (sigma2 * eta[p])
beta[p] ~ dnorm(0, omega[p])
}
Intercept ~ dnorm(0, 1e-10)
for (i in 1:N){
mu[i] <- Intercept + sum(beta[1:P] * X[i,1:P])
y[i] ~ dnorm(mu[i], tau)
log_lik[i] <- logdensity.norm(y[i], mu[i], tau)
ySim[i] ~ dnorm(mu[i], tau)
}
sigma <- sqrt(sigma2)
Deviance <- -2 * sum(log_lik[1:N])
}"
P <- ncol(X)
write_lines(jags_blasso, "jags_blasso.txt")
jagsdata <- list(X = X, y = y, N = length(y), P = ncol(X))
monitor <- c("Intercept", "beta", "sigma", "lambda", "Deviance", "ySim", "log_lik")
if (log_lik == FALSE){
monitor = monitor[-(length(monitor))]
}
inits <- lapply(1:chains, function(z) list("Intercept" = lmSolve(formula, data)[1],
"beta" = lmSolve(formula, data)[-1],
"eta" = rep(1, P),
"tau" = tau,
"lambda" = sample(2:10, size = 1),
"ySim" = sample(y, length(y)),
.RNG.name= "lecuyer::RngStream",
.RNG.seed= sample(1:10000, 1)))
out = run.jags(model = "jags_blasso.txt", modules = c("bugs on", "glm on", "dic off"), n.chains = chains, monitor = monitor, data = jagsdata, inits = inits, burnin = warmup, sample = iter, thin = thin, adapt = adapt, method = method, cl = cl, summarise = FALSE, ...)
file.remove("jags_blasso.txt")
if (!is.null(cl)) {
parallel::stopCluster(cl = cl)
}
return(out)
}
if (family == "st"){
resids = y - as.vector(lmSolve(formula , data) %*% t(model.matrix(formula, data)))
tau = prec(resids)
jags_blasso = "model{
tau ~ dgamma(.01, .01)
sigma2 <- 1/tau
lambda ~ dgamma(0.50, 0.20)
for (p in 1:P){
eta[p] ~ dexp(lambda^2 / 2)
omega[p] <- 1 / (sigma2 * eta[p])
beta[p] ~ dnorm(0, omega[p])
}
Intercept ~ dnorm(0, 1e-5)
for (i in 1:N){
mu[i] <- Intercept + sum(beta[1:P] * X[i,1:P])
y[i] ~ dt(mu[i], tau, 3)
log_lik[i] <- logdensity.t(y[i], mu[i], tau, 3)
ySim[i] ~ dt(mu[i], tau, 3)
}
sigma <- sqrt(sigma2)
Deviance <- -2 * sum(log_lik[1:N])
}"
P <- ncol(X)
write_lines(jags_blasso, "jags_blasso.txt")
jagsdata <- list(X = X, y = y, N = length(y), P = ncol(X))
monitor <- c("Intercept", "beta", "sigma", "lambda", "Deviance", "ySim", "log_lik")
if (log_lik == FALSE){
monitor = monitor[-(length(monitor))]
}
inits <- lapply(1:chains, function(z) list("Intercept" = lmSolve(formula, data)[1],
"beta" = lmSolve(formula, data)[-1],
"eta" = rep(1, P),
"tau" = tau * 3,
"lambda" = sample(2:10, size = 1),
"ySim" = sample(y, length(y)),
.RNG.name= "lecuyer::RngStream",
.RNG.seed= sample(1:10000, 1)))
out = run.jags(model = "jags_blasso.txt", modules = c("bugs on", "glm on", "dic off"), monitor = monitor, data = jagsdata, inits = inits, burnin = warmup, sample = iter, thin = thin, adapt = adapt, method = method, cl = cl, n.chains = chains, summarise = FALSE, ...)
file.remove("jags_blasso.txt")
if (!is.null(cl)) {
parallel::stopCluster(cl = cl)
}
return(out)
}
if (family == "binomial"){
jags_blasso = "model{
lambda ~ dgamma(0.50, 0.20)
for (p in 1:P){
eta[p] ~ dexp(lambda^2 / 2)
omega[p] <- 1 / (sigma2 * eta[p])
beta[p] ~ dnorm(0, omega[p])
}
Intercept ~ dnorm(0, 1e-10)
for (i in 1:N){
logit(psi[i]) <- Intercept + sum(beta[1:P] * X[i,1:P])
y[i] ~ dbern(psi[i])
log_lik[i] <- logdensity.bern(y[i], psi[i])
ySim[i] ~ dbern(psi[i])
}
Deviance <- -2 * sum(log_lik[1:N])
}"
P <- ncol(X)
write_lines(jags_blasso, "jags_blasso.txt")
jagsdata <- list(X = X, y = y, N = length(y), P = ncol(X), sigma2 = pow(mean(y), -1) * pow(1 - mean(y), -1))
monitor <- c("Intercept", "beta", "lambda", "Deviance", "ySim", "log_lik")
if (log_lik == FALSE){
monitor = monitor[-(length(monitor))]
}
inits <- lapply(1:chains, function(z) list("Intercept" = as.vector(coef(glmnet::glmnet(x = X, y = y, family = "binomial", lambda = 0.025, alpha = 0, standardize = FALSE))[1,1]),
"beta" = rep(0, P),
"eta" = rgamma(P, 2, 1),
"lambda" = sample(2:10, size = 1),
"ySim" = sample(y, length(y)),
.RNG.name= "lecuyer::RngStream",
.RNG.seed= sample(1:10000, 1)))
out = run.jags(model = "jags_blasso.txt", modules = c("bugs on", "glm on", "dic off"), monitor = monitor, data = jagsdata, inits = inits, burnin = warmup, sample = iter, thin = thin, adapt = adapt, method = method, cl = cl, summarise = FALSE, ...)
file.remove("jags_blasso.txt")
if (!is.null(cl)) {
parallel::stopCluster(cl = cl)
}
return(out)
}
if (family == "poisson"){
jags_blasso = "model{
lambda ~ dgamma(0.5 , 0.20)
for (p in 1:P){
eta[p] ~ dexp(lambda^2 / 2)
omega[p] <- 1 / (sigma2 * eta[p])
beta[p] ~ dnorm(0, omega[p])
}
Intercept ~ dnorm(0, 1e-10)
for (i in 1:N){
log(psi[i]) <- Intercept + sum(beta[1:P] * X[i,1:P])
y[i] ~ dpois(psi[i])
log_lik[i] <- logdensity.pois(y[i], psi[i])
ySim[i] ~ dpois(psi[i])
}
Deviance <- -2 * sum(log_lik[1:N])
}"
P <- ncol(X)
write_lines(jags_blasso, "jags_blasso.txt")
jagsdata <- list(X = X, y = y, N = length(y), P = ncol(X), sigma2 = pow(mean(y) , -1))
monitor <- c("Intercept", "beta", "lambda", "Deviance", "ySim", "log_lik")
if (log_lik == FALSE){
monitor = monitor[-(length(monitor))]
}
inits <- lapply(1:chains, function(z) list("Intercept" = as.vector(coef(glmnet::glmnet(x = X, y = y, family = "poisson", lambda = 0.025, alpha = 0, standardize = FALSE))[1,1]),
"beta" = rep(0, P),
"eta" = rgamma(P, 2, 1),
"lambda" = sample(2:10, size = 1),
"ySim" = sample(y, length(y)),
.RNG.name= "lecuyer::RngStream",
.RNG.seed= sample(1:10000, 1)))
out = run.jags(model = "jags_blasso.txt", modules = c("bugs on", "glm on", "dic off"), n.chains = chains, monitor = monitor, data = jagsdata, inits = inits, burnin = warmup, sample = iter, thin = thin, adapt = adapt, method = method, cl = cl, summarise = FALSE, ...)
file.remove("jags_blasso.txt")
if (!is.null(cl)) {
parallel::stopCluster(cl = cl)
}
return(out)
}
}
}
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