x_OP_y: Fast calculation of 'z <- x OP y' and 'z <- t(t(x) OP y)'

In HenrikBengtsson/matrixStats: Functions that Apply to Rows and Columns of Matrices (and to Vectors)

Fast calculation of 'z <- x OP y' and 'z <- t(t(x) OP y)'

Description

Fast calculation of 'z <- x OP y' and 'z <- t(t(x) OP y)', where OP can be +, -, *, and /. For + and *, na.rm = TRUE will drop missing values first.

Usage

x_OP_y(x, y, OP, xrows = NULL, xcols = NULL, yidxs = NULL,
  commute = FALSE, na.rm = FALSE)

t_tx_OP_y(x, y, OP, xrows = NULL, xcols = NULL, yidxs = NULL,
  commute = FALSE, na.rm = FALSE)

Arguments

x	A numeric or logical NxK matrix.
y	A numeric or logical vector of length L.
OP	A character specifying which operator to use.
xrows, xcols	A vector indicating subset of rows (and/or columns) to operate over 'x'. If NULL, no subsetting is done.
yidxs	A vector indicating subset of elements to operate over 'y'. If NULL, no subsetting is done.
commute	If TRUE, 'y OP x' ('t(y OP t(x))') is calculated, otherwise 'x OP y' ('t(t(x) OP y)').
na.rm	If TRUE, missing values are excluded.

Value

Returns a numeric NxK matrix.

Missing values

If na.rm = TRUE, then missing values are "dropped" before applying the operator to each pair of values. For instance, if x[1, 1] is a missing value, then the result of x[1, 1] + y[1] equals y[1]. If also y[1] is a missing value, then the result is a missing value. This only applies to additions and multiplications. For subtractions and divisions, argument na.rm is ignored.

Author(s)

Henrik Bengtsson

Examples

x <- matrix(c(1, 2, 3, NA, 5, 6), nrow = 3, ncol = 2)

# Add 'y' to each column
y <- 1:2
z0 <- x + y
z1 <- x_OP_y(x, y, OP = "+")
print(z1)
stopifnot(all.equal(z1, z0))


# Add 'y' to each row
y <- 1:3
z0 <- t(t(x) + y)
z1 <- t_tx_OP_y(x, y, OP = "+")
print(z1)
stopifnot(all.equal(z1, z0))

HenrikBengtsson/matrixStats documentation built on Nov. 15, 2024, 3:20 p.m.