Coerce to a random variable

Convert x to an rvar object.

as_rvar(x, dim = NULL, dimnames = NULL, nchains = NULL)

as_rvar_numeric(x, dim = NULL, dimnames = NULL, nchains = NULL)

as_rvar_integer(x, dim = NULL, dimnames = NULL, nchains = NULL)

as_rvar_logical(x, dim = NULL, dimnames = NULL, nchains = NULL)

Arguments

x

(multiple options) An object that can be converted to an rvar, such as a vector, array, or an rvar itself.

dim

(integer vector) One or more integers giving the maximal indices in each dimension to override the dimensions of the rvar to be created (see dim()). If NULL (the default), dim is determined by the input. NOTE: This argument controls the dimensions of the rvar, not the underlying array, so you cannot change the number of draws using this argument.

dimnames

(list) Character vectors giving the names in each dimension to override the names of the dimensions of the rvar to be created (see dimnames()). If NULL (the default), this is determined by the input. NOTE: This argument controls the names of the dimensions of the rvar, not the underlying array.

nchains

(positive integer) The number of chains. The default is 1.

Value

An object of class "rvar" (or one of its subtypes) representing a random variable.

Details

For objects that are already rvars, returns them (with modified dimensions if dim is not NULL).

For numeric or logical vectors or arrays, returns an rvar with a single draw and the same dimensions as x. This is in contrast to the rvar() constructor, which treats the first dimension of x as the draws dimension. As a result, as_rvar() is useful for creating constants.

While as_rvar() attempts to pick the most suitable subtype of rvar based on the type of x (possibly returning an rvar_factor or rvar_ordered), as_rvar_numeric(), as_rvar_integer(), and as_rvar_logical() always coerce the draws of the output rvar to be numeric, integer, or logical (respectively), and always return a base rvar, never a subtype.

See also

rvar() to construct rvars directly. See rdo(), rfun(), and rvar_rng() for higher-level interfaces for creating rvars.

Examples

# You can use as_rvar() to create "constant" rvars (having only one draw):
x <- as_rvar(1)
x
#> rvar<1>[1] mean ± sd:
#> [1] 1 ± NA 

# Such constants can be of arbitrary shape:
as_rvar(1:4)
#> rvar<1>[4] mean ± sd:
#> [1] 1 ± NA  2 ± NA  3 ± NA  4 ± NA 
as_rvar(matrix(1:10, nrow = 5))
#> rvar<1>[5,2] mean ± sd:
#>      [,1]     [,2]    
#> [1,]  1 ± NA   6 ± NA 
#> [2,]  2 ± NA   7 ± NA 
#> [3,]  3 ± NA   8 ± NA 
#> [4,]  4 ± NA   9 ± NA 
#> [5,]  5 ± NA  10 ± NA 
as_rvar(array(1:12, dim = c(2, 3, 2)))
#> rvar<1>[2,3,2] mean ± sd:
#> , , 1
#> 
#>      [,1]     [,2]     [,3]    
#> [1,]  1 ± NA   3 ± NA   5 ± NA 
#> [2,]  2 ± NA   4 ± NA   6 ± NA 
#> 
#> , , 2
#> 
#>      [,1]     [,2]     [,3]    
#> [1,]  7 ± NA   9 ± NA  11 ± NA 
#> [2,]  8 ± NA  10 ± NA  12 ± NA 
#> 

# as_rvar_numeric() coerces subtypes of rvar to the base rvar type
y <- as_rvar_factor(c("a", "b", "c"))
y
#> rvar_factor<1>[3] mode <entropy>:
#> [1] a <0>  b <0>  c <0> 
#> 3 levels: a b c
as_rvar_numeric(y)
#> rvar<1>[3] mean ± sd:
#> [1] 1 ± NA  2 ± NA  3 ± NA