[9fans] simulation and newsqueak

[9fans] simulation and newsqueak

[Skip Tavakkolian]

i need to build a monte carlo simulator to model a system.  i
was first thinking of using libthread and channels, etc.  but i'm
wondering if newsqueak would be a better fit. has it been used
for this?

the kenc specific pragmas in the sources on rob's site seem to hint
that it ran on plan9 at some point but i can't see it on sources?

Re: [9fans] simulation and newsqueak

[Pietro Gagliardi]

Have you done a port of Newsqueak to Plan 9? I tried using Rob's
original code (and failed, albeit not very miserably).

What do you mean by "monte carlo" - the solitaire? Perhaps a look at
the concept would be helpful.

On May 30, 2008, at 6:27 PM, Skip Tavakkolian wrote:

> i need to build a monte carlo simulator to model a system.  i
> was first thinking of using libthread and channels, etc.  but i'm
> wondering if newsqueak would be a better fit. has it been used
> for this?
>
> the kenc specific pragmas in the sources on rob's site seem to hint
> that it ran on plan9 at some point but i can't see it on sources?
>
>

Re: [9fans] simulation and newsqueak

[Iruata Souza]

On Fri, May 30, 2008 at 7:53 PM, Pietro Gagliardi <pietro10@mac.com> wrote:
> Have you done a port of Newsqueak to Plan 9? I tried using Rob's original
> code (and failed, albeit not very miserably).
>
> What do you mean by "monte carlo" - the solitaire? Perhaps a look at the
> concept would be helpful.
>

http://www.isv.uu.se/~ingelman/graduate_school/courses/montecarlo/

iru

Re: [9fans] simulation and newsqueak

[Bakul Shah]

On Fri, 30 May 2008 15:27:12 PDT Skip Tavakkolian <9nut@9netics.com>  wrote:
> i need to build a monte carlo simulator to model a system.  i
> was first thinking of using libthread and channels, etc.  but i'm
> wondering if newsqueak would be a better fit. has it been used
> for this?

Why Newsqueak?  Why not roll your own simulation kernel?
Basically you need

    new_thread(function, argument, stackksize);
    condition = new_condition();
    busy(how_many_time_units);
    wait(condition);
    signal(condition);
    yield();	// may be

You do need stack switching code in asm or use setjmp/longjmp
for it but the rest is pretty easy.  The scheduler is a
priority queue of (time-to-run,thread), each condition has a
list of waiter threads, busy(n) puts the current thread on
the schedule to run n time units in future, wait(cond) puts
the current thread on the waiter list of cond, signal(cond)
moves all waiter threads to the run-queue and yield()s etc.
This simulation kernel is likely to be more efficient than a
generic threads package.  As an example, on a 1.5Ghz P4 (IBM
T42) per thread context switch time is about 56ns for 1000
threads, increasing to about 490ns for 100,000 threads.

You can use one or more threads to generate random events
with whatever probabilistic distribution you want.

Re: [9fans] simulation and newsqueak

[Rob Pike]

The Unix source is on my web site.

-rob

Re: [9fans] simulation and newsqueak

[Pietro Gagliardi]

On May 31, 2008, at 1:29 AM, Rob Pike wrote:

> The Unix source is on my web site.
>
> -rob
>

And I had lots of problems porting that to Plan 9. It works well on my
Mac, though.

Re: [9fans] simulation and newsqueak

[Russ Cox]

> And I had lots of problems porting that to Plan 9.

This is a totally useless comment.
If you said something about what the
problems were, then maybe people
on the list might be more willing to help you.

9fans is a mailing list, not IRC.

Russ