Trace Plot of spifa Posterior Samples — plot

Draws MCMC traceplots (iteration vs. value) directly from a fitted spifa model, in one of two formats: faceted (facet = TRUE, the default; one panel per parameter, with its own free y-scale, so a slow-mixing or small-variance parameter isn't visually flattened by others sharing the same axis) or overlaid (facet = FALSE; all series on a single panel, for a quick glance at overall convergence).

Usage

plot_trace(
  x,
  select,
  facet = TRUE,
  burnin = 0,
  thin = 1,
  nshow = 10,
  ncol = 1,
  legend = NULL,
  ...
)

Arguments

x: A fitted spifa model.
select: Parameters to plot, passed to the variable argument of subset_draws: either a group name (e.g. "A", matching every parameter in that group) or one or more full indexed names (e.g. "c[1]", paste0("A[", 1:10, ",1]")).
facet: Logical; if TRUE (default), draw one panel per parameter; if FALSE, overlay every series on a single panel. See Description.
burnin: Number of initial iterations to discard.
thin: Thinning interval applied after burnin.
nshow: If select matches more than nshow parameters, a random (sorted) subsample of nshow of them is shown instead of all of them. Set to NULL to always show every matched parameter.
ncol: Number of columns in the facet grid (facet = TRUE only); defaults to a single column.
legend: Legend position (facet = FALSE only): one of "bottom", "right", "none", or a logical. Defaults to NULL, which shows the legend unless there are more than 10 series, since a legend that large stops being readable and can dwarf the plot itself.
...: Currently unused.

Value

A ggplot object.

Author

Erick A. Chacón-Montalván

Examples

# \donttest{
data(ipixuna)
samples <- spifa(items ~ 1, data = ipixuna, nfactors = 3, ngp = 0, niter = 1000)

plot_trace(samples, select = "c", facet = TRUE)

plot_trace(samples, select = "c", facet = FALSE)


# more than nshow (10) parameters: a random subsample is shown
plot_trace(samples, select = "A", facet = TRUE, nshow = 6)


# explicit selection instead of a random subsample
plot_trace(samples, select = paste0("A[", 1:10, ",1]"), facet = TRUE)

# }