Exponential Integral and Incomplete Gamma Function R package expint version 0.2-1 CRAN Task View: NumericalMathematics (https://CRAN.R-project.org/view=NumericalMathematics) 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 sub-directory example_API provides an implementation. C routines derived from the GNU Scientific Library <https://www.gnu.org/software/gsl/>. Software Depends: R (>= 3.3.0) Suggests: gsl, pracma Vincent Goulet <vincent.goulet@act.ulaval.ca> Comprehensive R Archive Network (CRAN) 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) GPL (>= 2) 2026-01-27 application/tgz https://CRAN.R-project.org/package=expint doi:10.32614/CRAN.package.expint