rfun {posterior} | R Documentation |
Create functions of random variables
Description
Function that create functions that can accept and/or produce rvar
s.
Usage
rfun(.f, rvar_args = NULL, rvar_dots = TRUE, ndraws = NULL)
Arguments
.f |
(multiple options) A function to turn into a function that accepts and/or produces random variables:
|
rvar_args |
(character vector) The names of the arguments of |
rvar_dots |
(logical) Should dots ( |
ndraws |
(positive integer). The number of draws used to construct new
random variables if no |
Details
This function wraps an existing function (.f
) such that it returns rvar
s containing
whatever type of data .f
would normally return.
The returned function, when called, executes .f
possibly multiple times, once for each draw of
the rvar
s passed to it, then returns a new
rvar
representing the output of those function evaluations. If the arguments contain no rvar
s,
then .f
will be executed ndraws
times and an rvar
with that many draws returned.
Functions created by rfun()
are not necessarily fast (in fact in some cases they may be very slow), but
they have the advantage of allowing a nearly arbitrary R functions to be executed against rvar
s
simply by wrapping them with rfun()
. This makes it especially useful as a prototyping
tool. If you create code with rfun()
and it is unacceptably slow for your application,
consider rewriting it using math operations directly on rvar
s (which should be fast),
using rvar_rng()
, and/or using operations directly on the arrays that back the rvar
s
(via draws_of()
).
Value
A function with the same argument specification as .f
, but which can accept and return
rvar
s.
See Also
Examples
rvar_norm <- rfun(rnorm)
rvar_gamma <- rfun(rgamma)
mu <- rvar_norm(10, mean = 1:10, sd = 1)
sigma <- rvar_gamma(1, shape = 1, rate = 1)
x <- rvar_norm(10, mu, sigma)
x