Exponential Integrals



Dieter Kaiser wrote:
> Before I continue the work on $specint I would like to wait to get some response
> to be sure the changes and extensions will work and are accepted.
> 
> Meanwhile I have implemented some routines for the Exponential Integrals as
> simplifying functions. The only function I have found in Maxima is $expint which
> can return numerical values for the Exponential integral E1 using the routine
> slatec:de1.

I think slatec includes routines for E1, Ei, Li and En.  Just weren't 
included in maxima because there weren't any implementations of these in 
maxima at that time.

> 
> I would like to suggest the following Maxima User functions:

These names are ok.  But I would suggest that we use Macsyma names, if 
they exist.  If not, then perhaps we should follow Mathematica or Maple.


> Because all Exponential Integrals can be represented as a Incomplete Gamma
> function for which $specint has an algorithm to get the Laplace transform, we
> might extend $specint to integrate the Exponential Integrals too.

We could also implement the incomplete gamma function.

> 
> Is the suggested extension of Exponential Integrals of interest for the project?

I think that's a great addition.

Ray