R/blasso.R

Defines functions blasso

Documented in blasso

#' 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)
  }

  }
}
abnormally-distributed/Bayezilla documentation built on Oct. 31, 2019, 1:57 a.m.