Comments for Thomas Løcke Being Incoherent

Comment on Concurrent Ada Programming by Thomas Løcke

Thomas Løcke — Fri, 18 May 2012 10:28:33 +0000

Hey Francois,

That’s some pretty awesome code you got going there! Thanks for linking it.

I used the Ada.Task_Identification package because it clearly shows that different tasks have different internal id’s, and it does so in a very beginner friendly way.

Also it’s nice to learn about the existence of the Ada.Task_* packages. They are very handy.

Comment on Concurrent Ada Programming by Francois

Francois — Fri, 18 May 2012 08:06:10 +0000

I just made a similar implementation of dispatching jobs in parallel.
See code at http://shootout.alioth.debian.org/u64q/program.php?test=regexdna&lang=gnat&id=3
in procedure Parallel_Count.
There is no need of the package Ada.Task_Identification;
After completion of job, the returning worker gives its job_nbr to the dispatcher.
Improvement in speed on a 4-core is limited to a factor of 3 wrt to single core.
9 jobs => 2 rounds with 4 cores + 1 round with 1 core. = 3

Comment on Concurrent Ada Programming by Thomas Løcke

Thomas Løcke — Thu, 17 May 2012 20:35:24 +0000

I know there’s a book on its way about concurrent programming in Haskell:

https://plus.google.com/u/0/107890464054636586545/posts/QTzpXhc8r8f
http://www.haskell.org/pipermail/haskell/2012-May/023328.html

I do plan on buying that book, but whether or not I’ll ever reach a level of Haskell competence to be able to compare its features to Ada I honestly don’t know.

What I do know is that both Ada and Haskell are awesomely nice languages.

Comment on Concurrent Ada Programming by Apoptose

Apoptose — Thu, 17 May 2012 18:30:40 +0000

No problemo, I’m glad I understand better how the code works now.

I know you have done some Haskell, do you plan to write some kind of comparison between concurrent programming in Ada and in Haskell?
Bye.

Comment on Concurrent Ada Programming by Thomas Løcke

Thomas Løcke — Thu, 17 May 2012 17:15:38 +0000

There we go! Thanks to Apoptose for catching that nasty little bug.

Prior to the fix I was completely abusing the fact that a task can die silently if exceptions aren’t handled. The worst part about that is that it is described here:

http://www.adaic.org/resources/add_content/standards/05rat/html/Rat-1-3-4.html

And I read that a short while ago when I started mucking around with the Ada.Task_* packages. My memory is failing me!

Comment on Concurrent Ada Programming by Thomas Løcke

Thomas Løcke — Thu, 17 May 2012 17:01:25 +0000

Hey Apoptose,

Try using this as the body of Get:

begin
Put_Line (“before: ” & J’Img);
Job := J;
J := J – 1;
Put_Line (“after: ” & J’Img);
end Get

You’ll see that J never goes below zero.

But you’re right, it’s not really pretty. I’ll fix it to make it more clear. Thanks for pointing it out.

edit: Blarg.. Can’t even read my own output any longer. It does go below 0 – sheesh. Fix on its way!

Comment on Concurrent Ada Programming by Apoptose

Apoptose — Thu, 17 May 2012 16:48:55 +0000

Hello,
there is something I don’t understand with your second example:

it seems that in the end, J gets lower than 0, so a Constraint_Error is raised in procedure Get, but no error message is displayed.

So if I understand well, the line
exit when A_Job < 1;
is useless because anyway the task exit because of Constraint_Error.

Why?

Comment on Why I Love Free and Open Source Software by Bryan Zutter

Bryan Zutter — Fri, 11 May 2012 16:34:53 +0000

This is a great article and very well written. Looking forward to more of your posts.

Comment on Why I Love Free and Open Source Software by Lettre d’information de la FSFE Février 2012. | ANDRE Ani et GNU/Linux

Sat, 04 Feb 2012 17:48:16 +0000

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Comment on Ada Programming on Slackware by Thomas Løcke

Thomas Løcke — Thu, 02 Feb 2012 06:13:14 +0000

Hey Patrick,

No problem, I’m just glad you made it work. And yea, I’ve been bitten by the PATH issue also. It’s a classic!