| dimScale {Matrix} | R Documentation |
Scale the Rows and Columns of a Matrix
Description
dimScale, rowScale, and colScale implement
D1 %*% x %*% D2, D %*% x, and x %*% D
for diagonal matrices D1, D2, and D with
diagonal entries d1, d2, and d, respectively.
Unlike the explicit products, these functions preserve dimnames(x)
and symmetry where appropriate.
Usage
dimScale(x, d1 = sqrt(1/diag(x, names = FALSE)), d2 = d1)
rowScale(x, d)
colScale(x, d)
Arguments
x |
a matrix, possibly inheriting from virtual class
|
d1, d2, d |
numeric vectors giving factors by which to scale
the rows or columns of |
Details
dimScale(x) (with d1 and d2 unset) is only
roughly equivalent to cov2cor(x). cov2cor
sets the diagonal entries of the result to 1 (exactly);
dimScale does not.
Value
The result of scaling x, currently always inheriting from
virtual class dMatrix.
It inherits from triangularMatrix if and only
if x does. In the special case of dimScale(x, d1, d2)
with identical d1 and d2, it inherits from
symmetricMatrix if and only if x does.
Author(s)
Mikael Jagan
See Also
Examples
n <- 6L
(x <- forceSymmetric(matrix(1, n, n)))
dimnames(x) <- rep.int(list(letters[seq_len(n)]), 2L)
d <- seq_len(n)
(D <- Diagonal(x = d))
(scx <- dimScale(x, d)) # symmetry and 'dimnames' kept
(mmx <- D %*% x %*% D) # symmetry and 'dimnames' lost
stopifnot(identical(unname(as(scx, "generalMatrix")), mmx))
rowScale(x, d)
colScale(x, d)