R/bootstrap.R

In brandmaier/semtree: Recursive Partitioning for Structural Equation Models

forest.sample <-
  function(dataset,
           mtry = 2,
           covariates = NULL,
           return.oob = F,
           type = "bootstrap") {
    if (mtry > 0) {
      # cov.ids <- which(names(dataset) %in% covariates)
      # sample length(cov.ids)-mtry of those to exclude
      # rem.ids <- sample(cov.ids, length(cov.ids)-mtry)
      # dataset <- dataset[, -rem.ids]
      dataset <- sampleColumns(dataset, covariates, mtry)
    }

    N <- dim(dataset)[1]

    if (type == "bootstrap") {
      indices <- sample(1:N, N, replace = T)
    } else if (type == "subsample") {
      indices <- sample(1:N, round(0.632 * N), replace = F)
    } else {
      stop("Error! Unknown resampling procedure!")
    }
    bootstrap.data <- dataset[indices, ]
    oob.indices <- setdiff(1:N, unique(indices))
    oob.data <- dataset[oob.indices, ]

    if (return.oob) {
      return(list(bootstrap.data = bootstrap.data, oob.data = oob.data))
    } else {
      return(bootstrap.data)
    }
  }