| compile {compiler} | R Documentation |
These functions provide an interface to a byte code compiler for R.
cmpfun(f, options = NULL)
compile(e, env = .GlobalEnv, options = NULL)
cmpfile(infile, outfile, ascii = FALSE, env = .GlobalEnv,
verbose = FALSE, options = NULL)
loadcmp(file, envir = .GlobalEnv, chdir = FALSE)
disassemble(code)
enableJIT(level)
compilePKGS(enable)
getCompilerOption(name, options)
setCompilerOptions(...)
f |
a closure. |
options |
list of named compiler options |
env |
the top level environment for the compiling. |
file,infile,outfile |
pathnames; outfile defaults to infile with a .Rc extension in place of any existing extension. |
ascii |
logical; should the compiled file be saved in ascii format? |
verbose |
logical; should the compiler show what is being compiled |
envir |
environment to evaluate loaded expressions in. |
chdir |
logical; change directory before evaluation? |
code |
byte code expression or compiled closure |
e |
expression to compile |
level |
integer; the JIT level to use |
enable |
logical; enable compiling packages if |
name |
character string; name of option to return |
... |
named compiler options to set |
The function cmpfun compiles the body of a closure and
returns a new closure with the same formals and the body replaced by
the compiled body expression.
compile compiles an expression into a byte code object; the
object can then be evaluated with eval.
cmpfile parses the expression in infile, compiles
them, and writes the compiled expressions to outfile. If
outfile is not provided, it is formed from infile by
replacing or appending a .Rc suffix.
loadcmp is used to load compiled files. It is similar to
sys.source, except that its default loading environment is the
global environment rather than the base environment.
disassemble produces a printed representation of the code
that may be useful to give a hint of what is going on.
enableJIT enables or disables just-in-time (JIT)
compilation. JIT is disabled if the argument is 0. If enable is
1 then closures are compiled before their first use. If enable
is 2, then in addition closures are also compiled before they are
duplicated (useful for some packages, like lattice, that store
closures in lists). If enable is 3 then in addition all loops
are compiled before they are executed. JIT can also be enabled by
starting R with the environment variable R_ENABLE_JIT set to
one of these values.
compilePKGS enables or disables compiling packages when they
are installed. This requires that the package use lazy loading as
compilation occurs as functions are written to the lazy loading data
base. This can also be enabled by starting R with the environment
variable R_COMPILE_PKGS set to a positive integer value.
Currently the compiler warns about a variety of things. It does
this by using cat to print messages. Eventually this should
use the condition handling mechanism.
The options argument can be used to control compiler operation.
There are currently three options: optimize,
suppressAll, and suppressUndefined. optimize
specifies the optimization level, which can be an integer form 0 to 3.
suppressAll should be a scalar logical; if TRUE no
messages will be shown. suppressUndefined can be TRUE to
suppress all messages about undefined variables, or it can be a
character vector of the names of variables for which messages should
not be shown.
getCompilerOption returns the value of the specified option.
The default value is returned unless a value is supplied in the
options argument; the options argument is primarily for
internal use. setCompilerOption sets the default option
values. It returns a named list of the previous values.
Calling the compiler a byte code compiler is actually a bit of a
misnomer: the external representation of code objects currently uses
int operands, and when compiled with gcc the internal
representation is actually threaded code rather than byte code.
Luke Tierney
# a simple example
f <- function(x) x+1
fc <- cmpfun(f)
fc(2)
disassemble(fc)
# old R version of lapply
la1 <- function(X, FUN, ...) {
FUN <- match.fun(FUN)
if (!is.list(X))
X <- as.list(X)
rval <- vector("list", length(X))
for(i in seq(along = X))
rval[i] <- list(FUN(X[[i]], ...))
names(rval) <- names(X) # keep `names' !
return(rval)
}
# a small variation
la2 <- function(X, FUN, ...) {
FUN <- match.fun(FUN)
if (!is.list(X))
X <- as.list(X)
rval <- vector("list", length(X))
for(i in seq(along = X)) {
v <- FUN(X[[i]], ...)
if (is.null(v)) rval[i] <- list(v)
else rval[[i]] <- v
}
names(rval) <- names(X) # keep `names' !
return(rval)
}
# Compiled versions
la1c <- cmpfun(la1)
la2c <- cmpfun(la2)
# some timings
x <- 1:10
y <- 1:100
system.time(for (i in 1:10000) lapply(x, is.null))
system.time(for (i in 1:10000) la1(x, is.null))
system.time(for (i in 1:10000) la1c(x, is.null))
system.time(for (i in 1:10000) la2(x, is.null))
system.time(for (i in 1:10000) la2c(x, is.null))
system.time(for (i in 1:1000) lapply(y, is.null))
system.time(for (i in 1:1000) la1(y, is.null))
system.time(for (i in 1:1000) la1c(y, is.null))
system.time(for (i in 1:1000) la2(y, is.null))
system.time(for (i in 1:1000) la2c(y, is.null))