R: Rollup Sparse Arrays

rollup {slam}

R Documentation

Rollup Sparse Arrays

Description

Rollup (aggregate) sparse arrays along arbitrary dimensions.

Usage

rollup(x, MARGIN, INDEX, FUN, ...)

## S3 method for class 'simple_triplet_matrix'
rollup(x, MARGIN, INDEX, FUN = sum, ...)
## S3 method for class 'simple_sparse_array'
rollup(x, MARGIN, INDEX, FUN = sum, ...)
## S3 method for class 'matrix'
rollup(x, MARGIN, INDEX, FUN = sum, ...)
## S3 method for class 'array'
rollup(x, MARGIN, INDEX, FUN = sum, ...)

Arguments

`x`	a sparse array containing numeric, integer, or logical values.
`MARGIN`	a vector giving the subscripts (names) of the dimensions to be rolled up.
`INDEX`	a corresponding (`list` of) `factor` (components) in the sense that `as.factor(f)` defines the grouping.
`FUN`	the name of the function to be applied.
`...`	optional arguments to `FUN`.

Details

Provides fast summation over the rows or columns of sparse matrices in simple_triplet-form.

Note that the default method tries to coerce x to array.

Value

An object of the same class as x where for class simple_triplet_matrix the values are always of type double. The dimnames are taken from (the components of) INDEX.

Note

If (a component of) INDEX contains NA values the corresponding positions are ignored.

Author(s)

Christian Buchta

Examples

##
x <- matrix(c(1, 0, 0, 2, 1, NA), nrow = 2, 
	    dimnames = list(A = 1:2, B = 1:3))
x
zz <- rollup(x, 2L, c(1,2,1), na.rm = TRUE)
zz
##
s <- as.simple_triplet_matrix(x)
z <- rollup(s, 2L, c(1,2,1), na.rm = TRUE)
identical(zz, as.matrix(z))
##
a <- as.simple_sparse_array(s)
z <- rollup(a, 2L, c(1,2,1), na.rm = TRUE)
identical(as.array(zz), as.array(z))
##
zz <- rollup(x, 2L, c(1,NA,1), na.rm = TRUE)
zz
##
z  <- rollup(s, 2L, c(1,NA,1), na.rm = TRUE)
identical(zz, as.matrix(z))
##
z  <- rollup(a, 2L, c(1,NA,1), na.rm = TRUE)
identical(as.array(zz), as.array(z))

[Package slam version 0.1-23 Index]