abIndex-class function

Class "abIndex" of Abstract Index Vectors

The "abIndex" class, short for Abstract Index Vector , is used for dealing with large index vectors more efficiently, than using integer (or numeric) vectors of the kind 2:1000000 or c(0:1e5, 1000:1e6).

Note that the current implementation details are subject to change, and if you consider working with these classes, please contact the package maintainers (packageDescription("Matrix")$Maintainer).

class

Objects from the Class

Objects can be created by calls of the form new("abIndex", ...), but more easily and typically either by as(x, "abIndex") where x is an integer (valued) vector, or directly by abIseq() and combination c(...) of such.

Slots

• kind:: a character string, one of ("int32", "double", "rleDiff"), denoting the internal structure of the abIndex object.

• x:: Object of class "numLike"; is used (i.e., not of length 0) only iff the object is not

   compressed, i.e., currently exactly when `kind != "rleDiff"`.
  

• rleD:: object of class "rleDiff", used for compression via rle.

Methods

• as.numeric, as.integer, as.vector: signature(x = "abIndex"): ...
• [: signature(x = "abIndex", i = "index", j = "ANY", drop = "ANY"): ...
• coerce: signature(from = "numeric", to = "abIndex"): ...
• coerce: signature(from = "abIndex", to = "numeric"): ...
• coerce: signature(from = "abIndex", to = "integer"): ...
• length: signature(x = "abIndex"): ...
• Ops: signature(e1 = "numeric", e2 = "abIndex"): These and the following arithmetic and logic operations are not yet implemented ; see Ops for a list of these (S4) group methods.
• Ops: signature(e1 = "abIndex", e2 = "abIndex"): ...
• Ops: signature(e1 = "abIndex", e2 = "numeric"): ...
• Summary: signature(x = "abIndex"): ...
• show: ("abIndex"): simple show method, building on show(<rleDiff>).
• is.na: ("abIndex"): works analogously to regular vectors.
• is.finite, is.infinite: ("abIndex"): ditto.

Note

This is currently experimental and not yet used for our own code. Please contact us (packageDescription("Matrix")$Maintainer), if you plan to make use of this class.

Partly builds on ideas and code from Jens Oehlschlaegel, as implemented (around 2008, in the GPL'ed part of) package ff.

See Also

rle (base) which is used here; numeric

Examples

showClass("abIndex")
ii <- c(-3:40, 20:70)
str(ai <- as(ii, "abIndex"))# note
ai # -> show() method

stopifnot(identical(-3:20,
                    as(abIseq1(-3,20), "vector")))