From help-octave-request at bevo dot che dot wisc dot edu  Wed Jan 19 12:18:18 2000
Subject: Re: downsimplex
From: etienne grossmann <etienne at anonimo dot isr dot ist dot utl dot pt>
To: bsapp at lanl dot gov
CC: fabian at tu-cottbus dot de, help-octave@bevo.che.wisc.edu,         etienne@isr.ist.utl.pt
Date: Wed, 19 Jan 2000 18:17:03 +0000 (WET)



  Hello
  
Ben Sapp wrote:
#  etienne grossmann wrote:
#  >   If you like, we should be able to write decent minimizing tools. It
#  > should be easier for 2 persons than for one.
#  > 
#  I agree.   I will help on this effort.   As a matter of fact I suggest
#  that you do not write any thing similar to lp(Linear Programming) in
#  Matlab.   I have a .oct file that is almos complete.  It will be very
                      ^^^^
                     Excuse my ignorance, I do not know 
                   what .oct files are; the html-doc doesn't
                    say much. 

#  similar to Matlabs lp in it's synopsis.  I hope that when it is finished
#  it can be put in octave and replace lp_solve which still needs to be
#  written.  

  Our matlab must be missing some toolboxes (certainly a good
budgetary measure), I can't find anything about "lp".

#  I assume from the discussion that downsimplex means the simplex method
#  of Nelder and Mead?  I only ask because lp uses the simplex method
#  also.  But, the simplex method of Nelder-Mead is much different than the
#  simplex method used in Linear Programming.   Both, however, reduce the
#  cost(or function) at every iteration.  So, both could be correctly
#  called downsimplex.  I guess we just need to agree on a terminology.   


  Yes, the "downhill simplex" I was speaking of is Nelder and Mead's,
for minimizing an arbitrary function. This is very easy to
program. The "lp" you are writing is for finding optima of a linear
function with linear inequality constraints, isn't it? This is a much
bigger program to write, if I get it correctly.

  The problem with my code (apart from bugs, I mean) is it's
synopsis, which I should simplify. I don't know if I should change the
way options are passed, or if I should change the way I explain the
passing of options.

  It would probably be easier for octave users if options were passed
to octave functions in a similar way , especially options that
represent the same quantities e.g. number of iterations etc.

  Any ideas on the subject ?

  Cheers,


  Etienne



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