brms (version 2.3.1)

stanvar: User-defined variables passed to Stan

Description

Prepare user-defined variables to be passed to Stan's data block. This is primarily useful for defining more complex priors and for refitting models without recompilation despite changing priors.

Usage

stanvar(x, name = NULL, scode = NULL)

Arguments

x

An R object containing data to be passed to Stan.

name

Optinal character string providing the desired variable name of the object in x. If NULL (the default) the variable name is directly infered from x.

scode

Optional line of Stan code to define the variable in Stan's data block. If NULL (the default), the Stan code is inferred based on the class of x.

Value

An object of class stanvars.

Examples

# NOT RUN {
bprior <- prior(normal(mean_intercept, 10), class = "Intercept")
stanvars <- stanvar(5, name = "mean_intercept")
make_stancode(count ~ Trt, epilepsy, prior = bprior, 
              stanvars = stanvars)
              
# define a multi-normal prior with known covariance matrix
bprior <- prior(multi_normal(M, V), class = "b")
stanvars <- stanvar(rep(0, 2), "M", scode = "  vector[K] M;") +
  stanvar(diag(2), "V", scode = "  matrix[K, K] V;") 
make_stancode(count ~ Trt + log_Base4_c, epilepsy,
              prior = bprior, stanvars = stanvars)

# }