aggMatrix: Aggregate Values Accross Rows of a Matrix

In SEEG-Oxford/seegMBG: Streamlined Model-Based Geostatistics Functions for the SEEG Research Group

Description

Apply a function columnwise to groups of rows in a matrix, according to a grouping index. Essentially applies the same tapply to multiple colums of a matrix.

Usage

aggMatrix(x, index, fun = sum, margin = 1, ...)

Arguments

x	a matrix containing numeric, complex, integer or logical values, or a data frame.
index	list of one or more factors, each of same length as dim(x)[1] (as in tapply). The elements are coerced to factors by as.factor.
fun	the function to be applied. In the case of functions like +, %*%, etc., the function name must be backquoted or quoted.
margin	over which margin should the operation take place (i.e. which margin matches index).
...	other arguments to be passed to fun.

Value

a matrix with dimensions dim(x)[1], length(index)

See Also

Other utility: badRows, cellIdx, expand, merge.formula, rowProds

Examples

x <- expand(rnorm(5), 3)
aggMatrix(x, c(1, 1, 1, 2, 2))

SEEG-Oxford/seegMBG documentation built on May 9, 2019, 11:08 a.m.