Compute and display a univariate averaged shifted histogram (polynomial kernel)

Description

See bin1 & ash1 for more information.

Usage

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stat_ash(mapping = NULL, data = NULL, geom = "area", position = "stack",
  ab = NULL, nbin = 50, m = 5, kopt = c(2, 2), na.rm = FALSE,
  show.legend = NA, inherit.aes = TRUE, ...)

Arguments

mapping

Set of aesthetic mappings created by aes or aes_. If specified and inherit.aes = TRUE (the default), is combined with the default mapping at the top level of the plot. You only need to supply mapping if there isn't a mapping defined for the plot.

data

A data frame. If specified, overrides the default data frame defined at the top level of the plot.

geom

Use to override the default Geom

position

Position adjustment, either as a string, or the result of a call to a position adjustment function.

ab

half-open interval for bins [a,b). If no value is specified, the range of x is stretched by 5% at each end and used the interval.

nbin

number of bins desired. Default 50.

m

integer smoothing parameter; Default 5.

kopt

vector of length 2 specifying the kernel, which is proportional to ( 1 - abs(i/m)^kopt(1) )i^kopt(2); (2,2)=biweight (default); (0,0)=uniform; (1,0)=triangle; (2,1)=Epanechnikov; (2,3)=triweight.

na.rm

If FALSE (the default), removes missing values with a warning. If TRUE silently removes missing values.

show.legend

logical. Should this layer be included in the legends? NA, the default, includes if any aesthetics are mapped. FALSE never includes, and TRUE always includes.

inherit.aes

If FALSE, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. borders.

...

other arguments passed on to layer. There are three types of arguments you can use here:

  • Aesthetics: to set an aesthetic to a fixed value, like color = "red" or size = 3.

  • Other arguments to the layer, for example you override the default stat associated with the layer.

  • Other arguments passed on to the stat.

Details

A sample of the output from stat_ash():

Figure: stat\_ash\_01.png

Aesthetics

geom_ash understands the following aesthetics (required aesthetics are in bold):

  • x

  • alpha

  • color

  • fill

  • linetype

  • size

Computed variables

density

ash density estimate

References

David Scott (1992), "Multivariate Density Estimation," John Wiley, (chapter 5 in particular).

B. W. Silverman (1986), "Density Estimation for Statistics and Data Analysis," Chapman & Hall.

Examples

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# compare
library(gridExtra)
set.seed(1492)
dat <- data.frame(x=rnorm(100))
grid.arrange(ggplot(dat, aes(x)) + stat_ash(),
             ggplot(dat, aes(x)) + stat_bkde(),
             ggplot(dat, aes(x)) + stat_density(),
             nrow=3)

cols <- RColorBrewer::brewer.pal(3, "Dark2")
ggplot(dat, aes(x)) +
  stat_ash(alpha=1/2, fill=cols[3]) +
  stat_bkde(alpha=1/2, fill=cols[2]) +
  stat_density(alpha=1/2, fill=cols[1]) +
  geom_rug() +
  labs(x=NULL, y="density/estimate") +
  scale_x_continuous(expand=c(0,0)) +
  theme_bw() +
  theme(panel.grid=element_blank()) +
  theme(panel.border=element_blank())