distributions3
, inspired by the eponynmous Julia
package, provides a
generic function interface to probability distributions.
distributions3
has two goals:
Replace the rnorm()
, pnorm()
, etc, family of functions with S3
methods for distribution objects
Be extremely well documented and friendly for students in intro stat classes.
The main generics are:
random()
: Draw samples from a distribution.pdf()
: Evaluate the probability density (or mass) at a point.cdf()
: Evaluate the cumulative probability up to a point.quantile()
: Determine the quantile for a given probability.
Inverse of cdf()
.You can install distributions3
with:
install.packages("distributions3")
You can install the development version with:
install.packages("devtools")
devtools::install_github("alexpghayes/distributions3")
The basic usage of distributions3
looks like:
library(distributions3)
X <- Bernoulli(0.1)
random(X, 10)
#> [1] 1 0 0 0 0 0 0 1 0 0
pdf(X, 1)
#> [1] 0.1
cdf(X, 0)
#> [1] 0.9
quantile(X, 0.5)
#> [1] 0
Note that quantile()
always returns lower tail probabilities. If
you aren’t sure what this means, please read the last several paragraphs
of vignette("one-sample-z-confidence-interval")
and have a gander at
the plot.
I am very happy to review PRs and provide advice on how to add new functionality to the package. Documentation improvements are particularly appreciated!
To add a new distribution, the best way to get started is to look at
R/Beta.R
and tests/testthat/test-Beta.R
, copy them, and modify them
for whatever new distribution you’d like to add.
Please note that distributions3
is released with a Contributor Code
of
Conduct.
By contributing to this project, you agree to abide by its terms.
For a comprehensive overview of the many packages providing various distribution related functionality see the CRAN Task View.
distr
is quite similar
to distributions
, but uses S4 objects and is less focused on
documentation.distr6
builds on
distr
, but uses R6 objectsfitdistrplus
provides extensive functionality for fitting various distributions
but does not treat distributions themselves as objectsAdd the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.