R/interface-read.R

In sakrejda/stannis: Handles output from Stan (mc-stan.org)

#' Read the parameter dimensions of the binary rewrite
#'
#' @param root where the rewrite is rooted.
#' @param name optionally name of a parameter to get dimensions from.
#' @return named list of parameter dimensions
#' @export
get_dimensions = function(root, name = NULL) {
  if (is.null(name)) {
    dim_path = file.path(root, 'dimensions.bin')
    name_path = file.path(root, 'names.bin')
    dims = .Call('get_dimensions', PACKAGE = 'stannis', dim_path, name_path) 
    return(dims)
  } else {
    dims = .Call('get_parameter_dimensions', root, name)
    return(dims)
  }
}

#' Read a specific parameter from the binary rewrite
#' 
#' @param root where the rewrite is rooted
#' @return array of parameter samples
#' @export
get_parameter = function(root, name, mmap = FALSE) {
  if (!dir.exists(root) || length(root) != 1) 
    stop("argument 'root' must be a path to a single directory.")
  if (!is.character(name) || length(name) != 1)
    stop("argument 'name' must be a length-1 character vector.")
  if (!mmap) {
    parameter = .Call('get_parameter', PACKAGE = 'stannis', root, name) 
    parameter = array(data = parameter[['data']], dim = parameter[['dims']])
  } else {
    parameter_path = file.path(root, paste0(name, '-reshape.bin'))
    parameter = mmap::mmap(parameter_path, mmap::real64())
    dim(parameter) = get_dimensions(root, name)
  }
  return(parameter)
}