Posterior predictions at specified times for given subjects and antigen/isotype

Generates draw-level posterior predictions of the antibody trajectory at user-specified time points, for one or more subjects and a selected antigen/isotype. This is a low-level helper used by residual-based posterior predictive diagnostics.

Usage

predict_posterior_at_times(model, ids, antigen_iso, times)

Arguments

model

A data frame of posterior draws in long format with columns: Subject, Iso_type, Chain, Iteration, Parameter, value.

ids

Character vector of subject IDs to include (matched against Subject).

antigen_iso

Character scalar specifying the antigen/isotype to include (matched against Iso_type).

times

Numeric vector of time points (days) at which to evaluate predictions.

Value

A tibble with one row per (posterior draw \(\times\) time \(\times\) subject), including the evaluated prediction res. Output includes at least:

id

Subject ID (character).

t

Time (days) at which prediction was evaluated.

Chain

MCMC chain index (if present in model).

Iteration

MCMC iteration index (if present in model).

sample_id

Row index for the draw (added if missing).

y0, y1, t1, alpha, shape

Model parameters (wide).

res

Predicted antibody level at time t.

Details

This function pivots posterior draws to wide format (parameters as columns), expands them over times, and evaluates the antibody curve via an internal implementation of the antibody kinetics model using parameters y0, y1, t1, alpha, and shape.

See also

compute_residual_metrics

Examples

if (FALSE) { # \dontrun{
preds <- predict_posterior_at_times(
  model = overall_sf2a,
  ids = "newperson",
  antigen_iso = "IgG",
  times = c(0, 30, 90, 180)
)
} # }