Re: [Help-glpk] Optimization and Multicore GLPK

[Harley]

Given this is the Christmas holiday period in Australia & NZ (except for ex-pats located in Berlin), 
I have only been catching up with this thread now.

I concur with Robbie about the choice of git for the version control for the project. I personally 
work everyday with Subversion, but for this type of community development, git is the standard and 
is well supported through github. As for the management of commits to the site, there are well 
established approaches for managing community development projects and it would make sense to have 
Andrew (possibly with some assistance or with others) maintaining control of the commitment process.

For those questioning the need for the requirement of re-entrant code for GLPK, I asked the same 
question and Xypron sent this answer to me by email:

"you are right that multiple processes may run GLPK at the same time. But many
applications like Apache or Tomcat are multi threaded. So maybe you would
like to create a webservice offering route optimization by solving a TSP. You
wouldn't be able to do so with the current GLPK because Apache has multiple
threads per worker process, and you definitely do not want to shut down
Apache if one of the TSPs has a problem because a user of your webservice
came up with some strange input."

For profiling and possible static analysis of the GLPK code, I seem to recall a commercial product 
that claimed to offer advanced static analysis and profiling of C code for optimisation and code 
reorganisation and were offering to allow use of the product for open source GPL projects for free. 
It claimed lots of benefits and its list of open source products that had used it were impressive, 
but I cant seem to recall the name of the product and I have no idea if their claims are in fact 
true. I will do some investigation to see if I can find it and then review what it offers to see if 
it may be of benefit for code review and to get ideas for code improvements.

Regards,

Harley

On 28/12/12 8:51 PM, Robbie Morrison wrote:
> Hi Reg, all
>
> ------------------------------------------------------------
> To:           glpk <address@hidden>
> Subject:      Re: [Help-glpk] Optimization and Multicore GLPK
> From:         Reginald Beardsley <address@hidden>
> Date:         Thu, 27 Dec 2012 16:45:00 -0800 (PST)
> ------------------------------------------------------------
>
> I just picked out a couple of points, mostly
> related to the process and not the technicalities.
> Note too that some of the original post has been
> reordered.
>
> PROBLEM STATEMENTS
>
> > The solution I understand.  The problem I don't.
> The problems being addressed need to be fully
> articulated and agreed upon.
>
> VERSION CONTROL
>
> > As for version control, there is a strong
> > benefit to having an accessible change history.
> > Particularly in tracking down bugs.  However, I
> > don't think there is any benefit to having
> > multiple people modifying the code in a
> > repository.  I think much preferable for people
> > to send proposed changes to Andrew and if he
> > accepts them they get integrated into the
> > repository.
> There are a number of workflows supported by
> distributed version control systems.  xypron (if I
> am not mistaken) has suggested this one in the
> past:
>
>    
> http://git-scm.com/book/en/Distributed-Git-Distributed-Workflows#Dictator-and-Lieutenants-Workflow
>
> > FWIW I don't like git and would suggest
> > mercurial instead.
> I think 'git' is, for better or worse, the default
> for open source projects these days.
>
> Bug tracking might also be helpful.  Again a
> workflow and a maintainer need to be assigned.
>
> CODE STYLE
>
> > A very serious issue in maintenance programming is
> > style.  Sadly very few programmers understand the
> > importance of matching the style of the existing
> > code.
> I doubt if there will be a problem with
> "incorrect" coding.  The current codebase is so
> utterly consistent.  Indeed, the style police
> would be better occupied looking thru my wardrobe.
>
> WIKIBOOK CHAPTER
>
> > Much more useful in my view is people taking on
> > chores like the wiki, setting up a profiling
> > system, testing on major platforms, etc.  Doing
> > what no one else is doing.
> Good point.
>
> I started marking up a wiki page:
>
>    http://en.wikibooks.org/wiki/GLPK/Sandbox_%28for_content_under_development%29
>
> The working title is: Code optimization and
> concurrent execution effort.  Let me know (Reg
> perhaps) if this can be improved upon.  Once the
> real page is made, this chapter title will (more
> or less) be set in stone.
>
> I'll continue to work on the content over the new
> year break.  All feedback gratefully received.
>
> Robbie
> ---
> Robbie Morrison
> PhD student -- policy-oriented energy system simulation
> Technical University of Berlin (TU-Berlin), Germany
> University email (redirected) : address@hidden
> Webmail (preferred)           : address@hidden
> [from Webmail client]
>
>
>
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>
> --
> ------------------------------------------------------------------
>       Dr. Harley Mackenzie         ABN:   36 348 783 012
>
>       HARD Software                Web:   www.hardsoftware.com
>       PO BOX 8004                  Tel:   +61 3 5222 3435
>       Newtown 3220, Australia      Email: address@hidden
> ------------------------------------------------------------------