Construct a parameter with a prior, weight and an update flag.

Usage

Param(
  init,
  weight = if_else(init == 0, 0, 1),
  update = weight > 0,
  prior = init
)

Arguments

init: the initial value of the parameter.
weight: the weight of the prior.
update: a flag indicating if the parameter shouldbe updated in the MCMC.
prior: mean value of the prior distribution, may be used with weight to fully determine prior parameters.

Value

A list with the following elements:

init the initial value of the parameter.
weight the weight of the prior.
update a flag indicating if the parameter shouldbe updated in the MCMC.
prior mean value of the prior distribution, may be used with weight to fully determine prior parameters.

Examples

# Fully specified parameter.
Param(init = 0, weight = 1, update = TRUE, prior = 0.5)
#> $init
#> [1] 0
#> 
#> $update
#> [1] TRUE
#> 
#> $prior
#> [1] 0.5
#> 
#> $weight
#> [1] 1
#> 
#> attr(,"class")
#> [1] "Param"
# Fixed parameter
# Weight = 0 implies update=FALSE and prior is ignored.
Param(0, 0)
#> $init
#> [1] 0
#> 
#> $update
#> [1] FALSE
#> 
#> $prior
#> [1] 0
#> 
#> $weight
#> [1] 0
#> 
#> attr(,"class")
#> [1] "Param"
# Update parameter that starts at zero.
Param(0, weight =1, update=TRUE)
#> $init
#> [1] 0
#> 
#> $update
#> [1] TRUE
#> 
#> $prior
#> [1] 0
#> 
#> $weight
#> [1] 1
#> 
#> attr(,"class")
#> [1] "Param"
# Parameters specified at zero implies fixed.
Param(0)
#> $init
#> [1] 0
#> 
#> $update
#> [1] FALSE
#> 
#> $prior
#> [1] 0
#> 
#> $weight
#> [1] 0
#> 
#> attr(,"class")
#> [1] "Param"