pmaxC: Parallel maximum/minimum

In hutilscpp: Miscellaneous Functions in C++

Parallel maximum/minimum

Description

Faster pmax() and pmin().

Usage

pmaxC(
  x,
  a,
  in_place = FALSE,
  keep_nas = FALSE,
  dbl_ok = NA,
  nThread = getOption("hutilscpp.nThread", 1L)
)

pminC(
  x,
  a,
  in_place = FALSE,
  keep_nas = FALSE,
  dbl_ok = NA,
  nThread = getOption("hutilscpp.nThread", 1L)
)

pmax0(
  x,
  in_place = FALSE,
  sorted = FALSE,
  keep_nas = FALSE,
  nThread = getOption("hutilscpp.nThread", 1L)
)

pmin0(
  x,
  in_place = FALSE,
  sorted = FALSE,
  keep_nas = FALSE,
  nThread = getOption("hutilscpp.nThread", 1L)
)

pmaxV(
  x,
  y,
  in_place = FALSE,
  dbl_ok = TRUE,
  nThread = getOption("hutilscpp.nThread", 1L)
)

pminV(
  x,
  y,
  in_place = FALSE,
  dbl_ok = TRUE,
  nThread = getOption("hutilscpp.nThread", 1L)
)

pmax3(x, y, z, in_place = FALSE)

pmin3(x, y, z, in_place = FALSE)

Arguments

x	numeric(n) A numeric vector.
a	numeric(1) A single numeric value.
in_place	TRUE | FALSE, default: FALSE Should x be modified in-place? For advanced use only.
keep_nas	TRUE | FALSE, default: FALSE Should NAs values be preserved? By default, FALSE, so the behaviour of the function is dependent on the representation of NAs at the C++ level.
dbl_ok	logical(1), default: NA Is it acceptable to return a non-integer vector if x is integer? This argument will have effect a is both double and cannot be coerced to integer: If NA, the default, a message is emitted whenever a double vector needs to be returned. If FALSE, an error is returned. If TRUE, neither an error nor a message is returned.
nThread	integer(1) The number of threads to use. Combining nThread > 1 and in_place = TRUE is not supported.
sorted	TRUE | FALSE, default: FALSE Is x known to be sorted? If TRUE, x is assumed to be sorted. Thus the first zero determines whether the position at which zeroes start or end.
y, z	numeric(n) Other numeric vectors the same length as x

Value

Versions of pmax and pmin, designed for performance.

When in_place = TRUE, the values of x are modified in-place. For advanced users only.

The differences are:

pmaxC(x, a) and pminC(x, a)

Both x and a must be numeric and a must be length-one.

Note

This function will always be faster than pmax(x, a) when a is a single value, but can be slower than pmax.int(x, a) when x is short. Use this function when comparing a numeric vector with a single value.

Use in_place = TRUE only within functions when you are sure it is safe, i.e. not a reference to something outside the environment.

By design, the functions first check whether x will be modified before allocating memory to a new vector. For example, if all values in x are nonnegative, the vector is returned.

Examples

pmaxC(-5:5, 2)
pmaxC(1:4, 5.5)
pmaxC(1:4, 5.5, dbl_ok = TRUE)
# pmaxC(1:4, 5.5, dbl_ok = FALSE)  # error

hutilscpp documentation built on Oct. 11, 2023, 9:06 a.m.