Mishra, Srikanta <MISHRAS <at> battelle.org> writes:
> 
> Is there an R function for evaluating the exponential integral
> 
> Ei(x) = INT(-inf,x) exp(t)/t dt
  Try the gsl package.
  Also library(sos); findFn("{exponential integral}")
although admittedly it doesn't find the Expint page
in the gsl package ...