colVars: Column and row-wise variances and standard deviations of a...

In Rfast: A Collection of Efficient and Extremely Fast R Functions

Column and row-wise variances and standard deviations of a matrix

Description

Column and row-wise variances and standard deviations of a matrix

Usage

## S3 method for class 'matrix'
colVars(x, std = FALSE, na.rm = FALSE, parallel = FALSE, cores = 0)
## S3 method for class 'data.frame'
colVars(x, std = FALSE, na.rm = FALSE, parallel = FALSE, cores = 0)
colVars(x, std = FALSE, na.rm = FALSE, parallel = FALSE, cores = 0)
rowVars(x, std = FALSE, na.rm = FALSE, parallel = FALSE, cores = 0)

Arguments

x	A matrix with the data.
std	A boolean variable specyfying whether you want the variances (FALSE) or the standard deviations (TRUE) of each column.
na.rm	TRUE or FAlSE for remove NAs if exists.
parallel	Should parallel implentations take place in C++? The default value is FALSE.
cores	Number of cores to use for parallelism. Valid only when argument parallel is set to TRUE. Default value is 0 and it means the maximum supported cores.

Details

We found this on stackoverflow which was created by David Arenburg. We then modified the function to match the sums type formula of the variance, which is faster.

Value

A vector with the column variances or standard deviations.

Author(s)

Michail Tsagris and Manos Papadakis.

R implementation and documentation: Michail Tsagris <[e-mail]> and Manos Papadakis <[e-mail]>.

See Also

colmeans, colMedians, colrange

Examples

x <- matrix( rnorm(100 * 100), ncol = 100 )
a2 <- colVars(x)
x<-a2<-NULL

Rfast documentation built on Nov. 9, 2023, 5:06 p.m.