matrixStats (version 0.51.0)

rowWeightedMedians: Calculates the weighted medians for each row (column) in a matrix

Description

Calculates the weighted medians for each row (column) in a matrix.

Usage

rowWeightedMedians(x, w=NULL, rows=NULL, cols=NULL, na.rm=FALSE, ...)
 colWeightedMedians(x, w=NULL, rows=NULL, cols=NULL, na.rm=FALSE, ...)

Arguments

x

A numeric NxK matrix.

w

A numeric vector of length K (N).

rows, cols

A vector indicating subset of rows (and/or columns) to operate over. If NULL, no subsetting is done.

na.rm

If TRUE, missing values are excluded from the calculation, otherwise not.

...

Additional arguments passed to weightedMedian().

Value

Returns a numeric vector of length N (K).

Details

The implementations of these methods are optimized for both speed and memory. If no weights are given, the corresponding rowMedians()/colMedians() is used.

See Also

See rowMedians() and colMedians() for non-weighted medians. Internally, weightedMedian() is used.

Examples

 x <- matrix(rnorm(20), nrow=5, ncol=4)
print(x)

# Non-weighted row averages
xM0 <- rowMedians(x)
xM <- rowWeightedMedians(x)
stopifnot(all.equal(xM, xM0))

# Weighted row averages (uniform weights)
w <- rep(2.5, ncol(x))
xM <- rowWeightedMedians(x, w=w)
stopifnot(all.equal(xM, xM0))

# Weighted row averages (excluding some columns)
w <- c(1,1,0,1)
xM0 <- rowMedians(x[,(w == 1),drop=FALSE]);
xM <- rowWeightedMedians(x, w=w)
stopifnot(all.equal(xM, xM0))

# Weighted row averages (excluding some columns)
w <- c(0,1,0,0)
xM0 <- rowMedians(x[,(w == 1),drop=FALSE]);
xM <- rowWeightedMedians(x, w=w)
stopifnot(all.equal(xM, xM0))

# Weighted averages by rows and columns
w <- 1:4
xM1 <- rowWeightedMedians(x, w=w)
xM2 <- colWeightedMedians(t(x), w=w)
stopifnot(all.equal(xM2, xM1))