asum: Sum over dimension margins

In spray: Sparse Arrays and Multivariate Polynomials

Sum over dimension margins

Description

Sum over specified dimension margins.

Usage

## S3 method for class 'spray'
asum(S, dims, drop=TRUE, ...)
asum_inverted(S, dims)
process_dimensions(S,dims)

Arguments

S	spray object
dims	Vector of strictly positive integers corresponding to dimensions to be summed over
drop	Boolean, with default TRUE meaning to drop the summed dimensions, and FALSE meaning to retain them.
...	Further arguments, currently ignored

Details

Function asum.spray() is the method for asum(). This takes a spray, and a vector of integers corresponding to dimensions to be summed over.

Function asum_inverted() is the same, but takes a vector of integers corresponding to dimensions not to sum over. This function is here because there is nice C++ idiom for it.

Function process_dimensions() ensures that the dims argument is consistent with the spray S and returns a cleaned version thereof.

Value

Returns a spray object.

Author(s)

Robin K. S. Hankin

Examples

S <- spray(matrix(sample(0:2,60,replace=TRUE),ncol=3),addrepeats=TRUE)
S

asum(S,1)
asum(S,1:2)

asum(S,1:2,drop=FALSE)


asum(S,c(1,3)) == asum_inverted(S,2)

spray documentation built on Sept. 11, 2024, 9:24 p.m.