Build a GAM formula dynamically

Usage

build_formula(
  target,
  covariates,
  smooth_terms = NULL,
  group_by = "group",
  participant_id = "subjectID",
  k
)

Arguments

target: Diffusion metric to model
covariates: List of strings of GAM covariates, not including the smoothing terms over nodes and the random effect due to subjectID. This list can also include smoothing terms.
smooth_terms: Smoothing terms, not including the smoothing terms over nodes and the random effect due to subjectID.
group_by: The grouping variable used to group nodeID smoothing terms
participant_id: The name of the column that encodes participant ID
k: Dimension of the basis used to represent the node smoothing term

Value

A GAM formula

Examples

formula <- build_formula(target = "dti_fa",
                         covariates = c("group", "sex"),
                         k = 40)
formula <- build_formula(target = "dki_md",
                         covariates = c("group", "sex", "s(age, by=sex)"),
                         k = 32)