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The exponential integrals E_1(x), E_2(x), E_n(x) and Ei(x), and the incomplete gamma function G(a, x) defined for negative values of its first argument. The package also gives easy access to the underlying C routines through an API; see the package vignette for details. A test package included in subdirectory example_API provides an implementation. C routines derived from the GNU Scientific Library <https://www.gnu.org/software/gsl/>.
Package details 


Author  Vincent Goulet [cre, aut], Gerard Jungman [aut] (Original GSL code), Brian Gough [aut] (Original GSL code), Jeffrey A. Ryan [aut] (Package API), Robert Gentleman [aut] (Parts of the R to C interface), Ross Ihaka [aut] (Parts of the R to C interface), R Core Team [aut] (Parts of the R to C interface), R Foundation [aut] (Parts of the R to C interface) 
Maintainer  Vincent Goulet <[email protected]> 
License  GPL (>= 2) 
Version  0.15 
URL  https://github.com/vigou3/expint 
Package repository  View on CRAN 
Installation 
Install the latest version of this package by entering the following in R:

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