Convert R-INLA Model Formulas into a GHRformulas Object

Description

This function converts a character vector of suitable R-INLA formulas into a structured GHRformulas object. The GHRformulas object contains the standardized information about the fixed effects, the random effects, and the outcome variable, ensuring consistency across multiple models to be fitted using the fit_models function.

as_GHRformulas(formulas)

Arguments

formulas: A character vector of model formulas formatted for R-INLA. Each formula must contain a single ~ separating the outcome variable from the predictors. Formulas generated with write_inla_formulas are compatible with this function.

Details

The as_GHRformulas() function parses each input formula to extract the outcome variable, fixed effects (covariates), and random effects. The resulting GHRformulas object is designed to be used with the fit_models function for model fitting with R-INLA.

Returns

A structured list of class GHRformulas with the following components:

formulas: A character vector of the original INLA-compatible model formulas.
vars: A data frame where each row corresponds to a formula and each column to a covariate. Entries indicate whether a covariate is included in the formula.
re: A character vector listing the random effects specified across all formulas.
outcome: A character string indicating the outcome variable (must be consistent across formulas).

Examples

formulas <- c(
"dengue_cases ~ 1 + f(month_id, model = 'rw1')", 
"dengue_cases ~ 1 + f(month_id, model = 'rw1') + tmin.l1") 

# Convert the formulas into a GHRformulas object
formulas <- as_GHRformulas(formulas)

# Inspect the structured GHRformulas object
print(formulas)
# Visualize output: GHRformulas object
class(formulas)