data.table (version 1.16.0)

fsort: Fast parallel sort

Description

Similar to base::sort but fast using parallelism. Experimental.

Usage

fsort(x, decreasing = FALSE, na.last = FALSE, internal=FALSE, verbose=FALSE, ...)

Value

The input in sorted order.

Arguments

x

A vector. Type double, currently.

decreasing

Decreasing order?

na.last

Control treatment of NAs. If TRUE, missing values in the data are put last; if FALSE, they are put first; if NA, they are removed; if "keep" they are kept with rank NA.

internal

Internal use only. Temporary variable. Will be removed.

verbose

Print tracing information.

...

Not sure yet. Should be consistent with base R.

Details

Process will raise error if x contains negative values. Unless x is already sorted fsort will redirect processing to slower single threaded order followed by subset in following cases:

• data type other than double (numeric)

• data having NAs

• decreasing==FALSE

Examples

x = runif(1e6)
system.time(ans1 <- sort(x, method="quick"))
system.time(ans2 <- fsort(x))
identical(ans1, ans2)