Simulation from Decay-adjusted Spatio-temporal (DAST) models

Simulates data from a fitted DAST model object (output from dast) or from user-specified DAST parameters.

Usage

dast_sim(
  n_sim,
  model_fit = NULL,
  formula = NULL,
  data = NULL,
  den = NULL,
  time = NULL,
  mda_times = NULL,
  int_mat = NULL,
  power_val = NULL,
  cov_offset = NULL,
  crs = NULL,
  convert_to_crs = NULL,
  scale_to_km = TRUE,
  sim_pars = list(beta = NULL, sigma2 = NULL, tau2 = NULL, phi = NULL, psi = NULL,
    sigma2_re = NULL, alpha = NULL, gamma = NULL),
  messages = TRUE
)

Arguments

n_sim: Number of simulations.
model_fit: Optional fitted DAST model object of class RiskMap. If supplied, it overrides model specification arguments.
formula: Model formula including a gp() term.
data: Data frame or sf object used for simulation.
den: Binomial denominator variable. If missing, it is assumed to be 1.
time: Survey-time information. For simulations from scratch this can be a column in data (unquoted name or character string) or a numeric vector of length nrow(data).
mda_times: Vector of MDA times.
int_mat: Intervention matrix (n x length(mda_times)) with coverage values.
power_val: Power value for the MDA impact function.
cov_offset: Optional offset for the linear predictor.
crs: Coordinate reference system (CRS) code.
convert_to_crs: Optional CRS to transform coordinates to before simulation.
scale_to_km: Logical; if TRUE distances are computed in kilometers.
sim_pars: List of simulation parameters. Used only when model_fit is NULL. Includes beta, sigma2, tau2, phi, psi, sigma2_re, alpha, and gamma.
messages: Logical; if TRUE print progress messages.

Value

A list with simulated outcomes in data_sim as an n x n_sim matrix (rows are observations, columns are simulations), simulated latent components and parameter values used for simulation.