sparseVector: Sparse Vector Construction from Nonzero Entries

In Matrix: Sparse and Dense Matrix Classes and Methods

Sparse Vector Construction from Nonzero Entries

Description

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

Usage

sparseVector(x, i, length)

Arguments

x	vector of the non zero entries; may be missing in which case a "nsparseVector" will be returned.
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.

Details

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

Value

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

Author(s)

Martin Maechler

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)))

(ns <- sparseVector(i= c(7, 3, 2), length = 10))
stopifnot(identical(ns,
      new("nsparseVector", length = 10, i = c(2, 3, 7))))

Matrix documentation built on Aug. 13, 2024, 3:01 p.m.