[Maxima] Exponential Integrals
drdieterkaiser at web.de
Tue Jul 8 14:41:50 CDT 2008
yes, I have found the additional slatec routines on the homepage of slatec
By inspection of the fortran code, I have seen that the slatec E1 routine uses
as an approximation method the evaluation of Chebyshev series.
I will do some tests to compare the accuracy of the slatec routines and an
algorithm which expand in a power series or uses continued fractions.
Von: raymond.toy at ericsson.com [mailto:raymond.toy at ericsson.com]
Gesendet: Dienstag, 8. Juli 2008 19:01
An: Dieter Kaiser
Cc: maxima at math.utexas.edu
Betreff: Re: [Maxima] Exponential Integrals
Dieter Kaiser wrote:
> Before I continue the work on $specint I would like to wait to get some
> 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
> can return numerical values for the Exponential integral E1 using the routine
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
I think that's a great addition.
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