Plot posterior smooths

## Usage

```
# S3 method for smooth_samples
draw(
object,
select = NULL,
n_samples = NULL,
seed = NULL,
xlab = NULL,
ylab = NULL,
title = NULL,
subtitle = NULL,
caption = NULL,
alpha = 1,
colour = "black",
contour = FALSE,
contour_col = "black",
n_contour = NULL,
scales = c("free", "fixed"),
rug = TRUE,
partial_match = FALSE,
angle = NULL,
ncol = NULL,
nrow = NULL,
guides = "keep",
...
)
```

## Arguments

- object
a fitted GAM, the result of a call to

`mgcv::gam()`

.- select
character, logical, or numeric; which smooths to plot. If

`NULL`

, the default, then all model smooths are drawn. Numeric`select`

indexes the smooths in the order they are specified in the formula and stored in`object`

. Character`select`

matches the labels for smooths as shown for example in the output from`summary(object)`

. Logical`select`

operates as per numeric`select`

in the order that smooths are stored.- n_samples
numeric; if not

`NULL`

, sample`n_samples`

from the posterior draws for plotting.- seed
numeric; random seed to be used to if sampling draws.

- xlab
character or expression; the label for the x axis. If not supplied, a suitable label will be generated from

`object`

.- ylab
character or expression; the label for the y axis. If not supplied, a suitable label will be generated from

`object`

.- title
character or expression; the title for the plot. See

`ggplot2::labs()`

.- subtitle
character or expression; the subtitle for the plot. See

`ggplot2::labs()`

.- caption
character or expression; the plot caption. See

`ggplot2::labs()`

.- alpha
numeric; alpha transparency for confidence or simultaneous interval.

- colour
The colour to use to draw the posterior smooths. Passed to

`ggplot2::geom_line()`

as argument`colour`

.- contour
logical; should contour lines be added to smooth surfaces?

- contour_col
colour specification for contour lines.

- n_contour
numeric; the number of contour bins. Will result in

`n_contour - 1`

contour lines being drawn. See`ggplot2::geom_contour()`

.- scales
character; should all univariate smooths be plotted with the same y-axis scale? If

`scales = "free"`

, the default, each univariate smooth has its own y-axis scale. If`scales = "fixed"`

, a common y axis scale is used for all univariate smooths.Currently does not affect the y-axis scale of plots of the parametric terms.

- rug
logical; draw a rug plot at the bottom of each plot for 1-D smooths or plot locations of data for higher dimensions.

- partial_match
logical; should smooths be selected by partial matches with

`select`

? If`TRUE`

,`select`

can only be a single string to match against.- angle
numeric; the angle at which the x axis tick labels are to be drawn passed to the

`angle`

argument of`ggplot2::guide_axis()`

.- ncol, nrow
numeric; the numbers of rows and columns over which to spread the plots

- guides
character; one of

`"keep"`

(the default),`"collect"`

, or`"auto"`

. Passed to`patchwork::plot_layout()`

- ...
arguments to be passed to

`patchwork::wrap_plots()`

.

## Examples

```
load_mgcv()
dat1 <- data_sim("eg1", n = 400, dist = "normal", scale = 1, seed = 1)
## a single smooth GAM
m1 <- gam(y ~ s(x0) + s(x1) + s(x2) + s(x3), data = dat1, method = "REML")
## posterior smooths from m1
sm1 <- smooth_samples(m1, n = 15, seed = 23478)
## plot
draw(sm1, alpha = 0.7)
## plot only 5 randomly smapled draws
draw(sm1, n_samples = 5, alpha = 0.7)
## A factor-by smooth example
dat2 <- data_sim("eg4", n = 400, dist = "normal", scale = 1, seed = 1)
## a multi-smooth GAM with a factor-by smooth
m2 <- gam(y ~ fac + s(x2, by = fac) + s(x0), data = dat2, method = "REML")
## posterior smooths from m1
sm2 <- smooth_samples(m2, n = 15, seed = 23478)
## plot, this time selecting only the factor-by smooth
draw(sm2, select = "s(x2)", partial_match = TRUE, alpha = 0.7)
# \donttest{
## A 2D smooth example
dat3 <- data_sim("eg2", n = 400, dist = "normal", scale = 1, seed = 1)
## fit a 2D smooth
m3 <- gam(y ~ te(x, z), data = dat3, method = "REML")
## get samples
sm3 <- smooth_samples(m3, n = 10)
## plot just 6 of the draws, with contour line overlays
draw(sm3, n_samples = 6, contour = TRUE, seed = 42)
# }
```