triplet {spam}

Transform a "spam" Format to Triplets

Description

Returns a list containing the indices and elements of a spam object.

Usage

triplet(x, tri=FALSE)

Arguments

x

sparse matrix of class spam or a matrix.

tri

Boolean indicating whether to create individual row and column indices vectors.

Details

The elements are row (column) first if x is a spam object (matrix).

Value

A list with elements

indices

a by two matrix containing the indices if tri=FALSE.

i, j

vectors containing the row and column indices if tri=TRUE.

values

a vector containing the matrix elements.

Author(s)

Reinhard Furrer

See Also

spam.creation for the inverse operation and foreign for other transformations.

Examples

x <- diag.spam(1:4)
x[2,3] <- 5
triplet(x)
all.equal( spam( triplet(x, tri=TRUE)), x)