Matrix (version 1.0-9)

sparseVector: Sparse Vector Construction from Nonzero Entries

Description

User friendly construction sparse vectors, i.e., objects inheriting from class sparseVector, from indices and values of its nonzero entries.

Usage

sparseVector(x, i, length)

Arguments

x

vector of the non zero entries.

i

integer vector (of the same length as x) specifying the indices of the non-zero (or non-TRUE) entries of the sparse vector.

length

length of the sparse vector.

Value

• a sparse vector, i.e., inheriting from class sparseVector.

Details

zero entries in x are dropped automatically, analogously as drop0() acts on sparse matrices.

See Also

sparseMatrix() constructor for sparse matrices; the class sparseVector.

Examples

str(sv <- sparseVector(x = 1:10, i = sample(999, 10), length=1000))

sx <- c(0,0,3, 3.2, 0,0,0,-3:1,0,0,2,0,0,5,0,0)
ss <- as(sx, "sparseVector")
stopifnot(identical(ss,
   sparseVector(x = c(2, -1, -2, 3, 1, -3, 5, 3.2),
                i = c(15L, 10:9, 3L,12L,8L,18L, 4L), length = 20L)))