Generalised AXPBY operation

Computes the linear combination \(Y := \alpha X + \beta Y\) in place.

Usage

dvcal(N = NULL, ALPHA = 1, X, INCX = 1L, BETA = 1, Y, INCY = 1L)

Arguments

N

Optional integer giving the number of elements. Defaults to `length(X)`.

ALPHA

Numeric scalar multiplying `X`.

X

Double-precision vector, matrix or [`bigmemory::big.matrix`] input.

INCX

Integer stride for traversing `X`.

BETA

Numeric scalar multiplying `Y`.

Y

Double-precision object updated in place.

INCY

Integer stride for traversing `Y`.

Value

Invisibly returns the modified `Y`.

Examples

x <- 1:5
y <- rep(2, 5)
dvcal(ALPHA = 2, X = x, BETA = -1, Y = y)
y
#> [1] 0 2 4 6 8