Re: [Contiki-developers] Cooja: random seed

[Fredrik Ö. <fr...@si...>]

(Sorry Joris, I missed your initial response ;) )

Andrea: I just committed a fix for Cooja motes, they didn't properly 
initialize the random library. You'll need to update both platform/cooja 
and tools/cooja from CVS.

Note also that if you reload a simulation (via Crtl+R), COOJA will load 
it using *the same* random seed.
(Reloading via Ctrl+Shift+R will however change the seed.)

Best,
Fredrik

Andrea Martelli skrev:
> I'm using Cooja type motes and I've followed your suggestion but I 
> still can't see great differences in the timeline.
> I will investigate it better.
>
> Thanks!
>
> Andrea
>
> 2010/4/30 Borms Joris <jb...@et... 
> <mailto:jb...@et...>>
>
>     I assume you are using the random functions from lib/random? Are
>     you using Cooja type motes or emulated sky motes?
>
>     In the latter case, each node should have a different random seed,
>     since the seed is set (using node ID) during initialization
>     (platform/sky/contiki-sky-main.c).
>
>     In either case, you could always call the "random_init(unsigned
>     short seed)" function to manually set a seed. Something like
>     "random_init(*(uint16_t*)(&rimeaddr_node_addr))" should probably
>     do the trick.
>
>     Joris
>
>
>
>     From: Andrea Martelli [mailto:and...@gm...
>     <mailto:and...@gm...>]
>     Sent: Friday, April 30, 2010 10:57 AM
>     To: con...@li...
>     <mailto:con...@li...>
>     Subject: [Contiki-developers] Cooja: random seed
>
>     Hello guys,
>
>     I'm doing some simulations in Cooja and the random seed seems to
>     be the same for every node.
>     On each node I scheduled timer-dependent data transmissions, with
>     a timer set to a PERIODIC + RANDOM interval. Whatching the
>     timeline in Cooja, it every node try to transmit at the same time,
>     and I have a lot of collisions!
>
>     How can I choose a different random seed for each node?
>
>
>     Andrea Martelli
>
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-- 
Fredrik Österlind <fr...@si...>, +46706641502