Re: execution speed in *oct files

[John W. Eaton]

On  8-Jun-1999, Thomas Walter <address@hidden> wrote:

| I think some of those reading this mailing list know about 'GSL', the
| 'GNU scientific library'.  They encoded the blas in C if I understand
| the code right.  Have a large number of random number generators and
| distribution generators.
| 
| Perhaps anybody with more knewledge about the needs for octave may
| have a look at it.  The current version of 'gsl' as tar archive can be
| found at
|       ftp://alpha.gnu.org/gnu/gsl-0.4.1.tar.gz

The TODO file for this library says

  These are the public domain packages we should convert to C and put
  under the GPL:

  fftpack -- mostly done (sine and cosine transforms still to do, want
             to add 2-d ffts, N-d ffts, convolutions)
  quadpack -- in progress (Brian)
  specfun -- in progress (Jerry)
  ranlib --  add the stuff we don't have
  minpack -- 
  odepack --
  blas --  
  starpac -- 
  dassl --
  eispack --
  lapack  -- 
  linpack -- 
  any others ???

I do understand that desire to have a better interface to these
subroutines (that's why I decided to wrap them in C++ classes) but I
don't fully understand the motivation for converting the original
Fortran code to C.  My reasoning for leaving the original code mostly
alone was along the lines of `if it ain't broke, don't fix it'.

I'm assuming that these translations are done at least partly, if not
completely, by hand, so if someone does make a bug fix or release a
new version of any of these packages (although relatively infrequent,
it does happen -- daspk is a newer version of dassl, for example) then
you have to work the fixes back into your translated version instead
of just updating the Fortran sources.  To me, that seems like a lot of
unnecessary work and also maybe asking for some trouble.

I do understand that mixed-language programming can be somewhat
tricky, but if all you ever want to do is call Fortran from C or C++,
it is not really all that bad in practice.  So why go to all the
trouble?  A quick look at the GSL docs and sources didn't turn up any
rationale or motivation for doing the translation.  Can anyone shed
any light on this?

Thanks,

jwe



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