plm (version 2.4-0)

plm.fast: Option to Switch On/Off Fast Data Transformations

Description

A significant speed up can be gained by using fast (panel) data transformation functions from package collapse.

Details

By default, this speed up is not enabled. Option plm.fast can be used to enable/disable the speed up. The option is evaluated prior to execution of supported transformations (see below), so option("plm.fast" = TRUE) enables the speed up while option("plm.fast" = FALSE) disables the speed up.

To have it always switched on, put options("plm.fast" = TRUE) in your .Rprofile file.

See Examples for how to use the option and for a benchmarking example.

By default, package plm uses base R implementations and R-based code. The package collapse provides fast data transformation functions written in C/C++, among them some especially suitable for panel data. Having package collapse installed is a requirement for the speed up. However, this package is currently not a hard dependency for package plm but a 'Suggests' dependency.

Currently, these functions benefit from the speed-up (more functions are under investigation):

• between,

• Between,

• Sum,

• Within.

Examples

# NOT RUN {
### A benchmark plm without and with speed-up
library("plm")
library("collapse")
library("microbenchmark")
rm(list = ls())
data("wlddev", package = "collapse")
form <- LIFEEX ~ PCGDP + GINI

# produce big data set (taken from collapse's vignette)
wlddevsmall <- get_vars(wlddev, c("iso3c","year","OECD","PCGDP","LIFEEX","GINI","ODA"))
wlddevsmall$iso3c <- as.character(wlddevsmall$iso3c)
data <- replicate(100, wlddevsmall, simplify = FALSE)
rm(wlddevsmall)
uniquify <- function(x, i) {
	x$iso3c <- paste0(x$iso3c, i)
	x
}
data <- unlist2d(Map(uniquify, data, as.list(1:100)), idcols = FALSE)
data <- pdata.frame(data, index = c("iso3c", "year"))
pdim(data) # Balanced Panel: n = 21600, T = 59, N = 1274400 // but many NAs
# data <- na.omit(data)
# pdim(data) # Unbalanced Panel: n = 13300, T = 1-31, N = 93900

options("plm.fast" = FALSE) # default: fast functions of 'collapse' not in use
times <- 3 # no. of repetitions for benchmark - this takes quite long!
bench_res_plm_baseR <- microbenchmark(
  plm(form, data = data, model = "within"),
  plm(form, data = data, model = "within", effect = "twoways"),
  plm(form, data = data, model = "random"),
  plm(form, data = data, model = "random", effect = "twoways"),
 times = times)

options("plm.fast" = TRUE)
bench_res_plm_collapse <- microbenchmark(
  plm(form, data = data, model = "within"),
  plm(form, data = data, model = "within", effect = "twoways"),
  plm(form, data = data, model = "random"),
  plm(form, data = data, model = "random", effect = "twoways"),
 times = times)
print(bench_res_plm_baseR,    unit = "s")
print(bench_res_plm_collapse, unit = "s")
# }