Sampler Function

Description

This is a wrapper for the sampling funcions of the vdg package. It extracts design properties from the design passed to it to take appropriate samples.

Usage

1
2
sampler(n, design, type = c("spherical", "cuboidal", "lhs", "mlhs", "slhs",
  "rslhs", "custom"), at = FALSE, custom.fun = NULL, ...)

Arguments

n

number of points to sample

design

design for which the sample is required (either a matrix or data frame)

type

type of design region/sampling method. One of "spherical", "cuboidal", "lhs", "mlhs", "slhs", "rslhs" or "custom". Option "custom" requires custom.fun to be non-NULL.

at

logical; should sampling be done on the surface of hyperspheres or hypercubes? Not used for LHS methods.

custom.fun

A custom sampling function, used in conjunction with type = "custom". The first and second arguments must be the sample size and dimension respectively.

...

other arguments passed to the underlying sampling functions.

Value

Matrix with samples as rows, with S3 class smpl

Author(s)

Pieter C. Schoonees

References

Pieter C. Schoonees, Niel J. le Roux, Roelof L.J. Coetzer (2016). Flexible Graphical Assessment of Experimental Designs in R: The vdg Package. Journal of Statistical Software, 74(3), 1-22. \Sexpr[results=rd,stage=build]{tools:::Rd_expr_doi("10.18637/jss.v074.i03")}.

See Also

runif_sphere, runif_cube, LHS, MLHS, SLHS, RSLHS

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
## Default spherical design region
set.seed(1896)
samp1 <- sampler(n = 100, design = expand.grid(x = -1:1, y = -1:1))
plot(samp1)

## Supplying a custom sampling function based on lhs::improvedLHS()
library("lhs")
sfun <- function(n, k, dup = 1) 2 * improvedLHS(n, k, dup = dup) - 1
samp2 <- sampler(n = 100, design = expand.grid(x = -1:1, y = -1:1),
                 type = "custom", custom.fun = sfun)
plot(samp2)