This function plots posterior empirical quantiles for a series-specific smooth term
Usage
plot_mvgam_smooth(
object,
trend_effects = FALSE,
series = 1,
smooth,
residuals = FALSE,
n_resid_bins = 25,
realisations = FALSE,
n_realisations = 15,
derivatives = FALSE,
newdata
)
Arguments
- object
list
object of classmvgam
. Seemvgam()
- trend_effects
logical. If
TRUE
and atrend_formula
was used in model fitting, terms from the trend (i.e. process) model will be plotted- series
integer
specifying which series in the set is to be plotted- smooth
Either a
character
orinteger
specifying which smooth term to be plotted- residuals
logical
. IfTRUE
, posterior quantiles of partial residuals are added to plots of 1-D smooths as a series of ribbon rectangles. Partial residuals for a smooth term are the median Dunn-Smyth residuals that would be obtained by dropping the term concerned from the model, while leaving all other estimates fixed (i.e. the estimates for the term plus the original median Dunn-Smyth residuals). Note that becausemvgam
works with Dunn-Smyth residuals and not working residuals, which are used bymgcv
, the magnitudes of partial residuals will be different to what you would expect fromplot.gam
. Interpretation is similar though, as these partial residuals should be evenly scattered around the smooth function if the function is well estimated- n_resid_bins
integer
specifying the number of bins to group the covariate into when plotting partial residuals. Setting this argument too high can make for messy plots that are difficult to interpret, while setting it too low will likely mask some potentially useful patterns in the partial residuals. Default is25
- realisations
logical
. IfTRUE
, posterior realisations are shown as a spaghetti plot, making it easier to visualise the diversity of possible functions. IfFALSE
, the default, empirical quantiles of the posterior distribution are shown- n_realisations
integer
specifying the number of posterior realisations to plot, ifrealisations = TRUE
. Ignored otherwise- derivatives
logical
. IfTRUE
, an additional plot will be returned to show the estimated 1st derivative for the specified smooth (Note: this only works for univariate smooths)- newdata
Optional
dataframe
for predicting the smooth, containing at least 'series' in addition to any other variables included in the linear predictor of the original model'sformula
. Note that this currently is only supported for plotting univariate smooths
Details
Smooth functions are shown as empirical quantiles (or spaghetti
plots) of posterior partial expectations across a sequence of values
between the variable's min
and max
, while zeroing out
effects of all other variables. At present, only univariate and bivariate
smooth plots are allowed, though note that bivariate smooths rely on
default behaviour from plot.gam
. plot_mvgam_smooth
generates posterior predictions from an object of class mvgam
,
calculates posterior empirical quantiles and plots them. If
realisations = FALSE
, the returned plot shows 90, 60, 40 and 20 percent
posterior quantiles (as ribbons of increasingly darker shades of red) as
well as the posterior median (as a dark red line). If
realisations = TRUE
, a set of n_realisations
posterior draws are
shown. For more nuanced visualisation, supply newdata
just as you
would when predicting from a gam
model or use the more
flexible conditional_effects.mvgam
. Alternatively, if you
prefer to use partial effect plots in the style of gratia
, and if you
have the gratia
package installed, you can use draw.mvgam
. See
gratia_mvgam_enhancements
for details.