R: Row Sums/Means of Sparse Symmetric Matrices

rowSums.dist {proxy} | R Documentation

## Row Sums/Means 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)

    colSums.dist(x, na.rm = FALSE)
    colMeans.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?

### 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 symmetry the result is always the same as for `rowSums` or `rowMeans`.

### Value

A numeric vector of row sums.

### Author(s)

Christian Buchta

### 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)

[Package proxy version 0.4-22 Index]