cba (version 0.2-5)

rowSums.dist: Row Sums of Sparse Symmetric Matrices

Description

Compute the row (column) sums or means for a sparse symmetric (distance) matrix.

Usage

rowSums.dist(x, na.rm = FALSE)
rowMeans.dist(x, na.rm = FALSE, diag = TRUE)

Arguments

x

an object of class dist.

na.rm

logical, should missing values (including NaN) be omitted from the summation?

diag

logical, should the diagonal elements be included in the computation?

Value

• A numeric vector of row sums.

Details

These functions are more efficient than expanding an object of class dist to matrix and using rowSums or rowMeans.

colSums and colMeans are provided for convenience. However, note that due to symmetricity the result is always the same as for rowSums or rowMeans.

See Also

as.matrix, as.dist, and rowSums.

Examples

## 
x <- matrix(runif(10*2),ncol=2)
d <- dist(x)
rowSums(as.matrix(d))
rowSums.dist(d)			# the same

rowMeans(as.matrix(d))
rowMeans.dist(d)		# the same
rowMeans.dist(d, diag = FALSE)	# not the same
## NAs
d[3] <- NA
rowSums.dist(d, na.rm = TRUE)
rowMeans.dist(d, na.rm = TRUE)