Row and column diagonal scaling

Scale each row or column of a matrix by a numeric vector, equivalent to left- or right-multiplying by a diagonal matrix. rowscale computes diag(d) %*% X (row \(i\) scaled by d[i]); colscale computes X %*% diag(d) (column \(j\) scaled by d[j]).

Usage

rowscale(X, d)

colscale(X, d)

Arguments

X

A matrix or aMatrix object.

d

Numeric vector of scale factors. Length must equal nrow(X) for rowscale and ncol(X) for colscale.

Value

A matrix or aMatrix of the same dimensions as X.

Examples

m <- matrix(1:6, 2, 3)
rowscale(m, c(2, 0.5))
#> An amatrix dense matrix [cpu|policy=auto|precision=strict]
#> 2 x 3 Matrix of class "adgeMatrix"
#>      [,1] [,2] [,3]
#> [1,]    2    6   10
#> [2,]    1    2    3
colscale(m, c(1, 2, 3))
#> An amatrix dense matrix [cpu|policy=auto|precision=strict]
#> 2 x 3 Matrix of class "adgeMatrix"
#>      [,1] [,2] [,3]
#> [1,]    1    6   15
#> [2,]    2    8   18