distributions3
, inspired by the eponynmous Julia
package, provides a
generic function interface to probability distributions. distributions
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()
.distributions
is not yet on CRAN. 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] 0 0 0 0 0 0 0 0 0 1
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 objectsAny scripts or data that you put into this service are public.
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