biotools (version 1.2)

findSubsample: Finding an Optimized Subsample

Description

It allows one to find an optimized (minimized or maximized) numeric subsample according to a statistic of interest. For example, it might be of interest to determine a subsample whose standard deviation is the lowest among all of those obtained from all possible subsamples of the same size.

Usage

findSubsample(x, size, fun = sd, minimize = TRUE, niter = 10000)

Arguments

x

a numeric vector.

size

an integer; the size of the subsample.

fun

an object of class function; the statistic at which to evaluate the subsample.

minimize

logical; if TRUE (default) findSubsample will find a subsample that minimizes stat.

niter

an integer indicating the number of iterations, i.e., the number of subsamples to be selected (without replacement) from the original sample, x. The larger is this number, the more optimized is the subsample to be found, but this also imp

Value

• A list of
• dataname
  a character.
• niter
  the number of iterations.
• fun
  the objective function.
• stat
  the achieved statistic for the optimized subsample.
• criterion
  a character indicating the type of optimization.
• subsample
  a numeric vector; the optimized subsample.
• labels
  a string containg the labels of the subsample values.

See Also

sample, creategroups

Examples

# Example 1
y <- rnorm(40, 5, 2)
findSubsample(x = y, size = 6)

# Example 2
f <- function(x) diff(range(x)) # max(x) - min(x)
findSubsample(x = y, size = 6, fun = f, minimize = FALSE, niter = 20000)

# End (not run)