Probably not – I bet it compiles the same RandomC as it does for a real node, so it still seeds based on TOS_NODE_ID. I have no idea if you can access “outside” sources of randomness from a TOSSIM node.
From: [email protected] [mailto:[email protected]] On Behalf Of Michiel Konstapel Sent: Thursday, July 10, 2014 16:17 To: Jisha Mary Jose Cc: Tinyos-Help Subject: Re: [Tinyos-help] random number Hi! Please keep replies on the list, so others can contribute/benefit, too. I’m not familiar with TOSSIM, so I just googled ‘TOSSIM random seed’ and looks like you can initialize its random number generator: http://tinyos-help.10906.n7.nabble.com/Reproducible-TOSSIM-simulations-td16341.html. This person has the opposite problem, trying to get reproducible run. However, I don’t know if the Tossim seed is used by the random number generator. From: Jisha Mary Jose [mailto:[email protected]] Sent: Thursday, July 10, 2014 12:16 To: Michiel Konstapel Subject: Re: [Tinyos-help] random number Hi, Thankyou for the response. I am working in TOSSIM, so there are no real motes. What is any other option to generate random numbers? Please guide me.. Regards, Jisha Mary Jose ......jMj...... On 10 July 2014 15:21, Michiel Konstapel <[email protected]<mailto:[email protected]>> wrote: Timer.getNow() starts over at zero after every boot, so you’re probably using the same seed every time unless something during the boot process takes a variable amount of time (and on an embedded system or in the simulator, it probably takes the same amount of time, every time – at least down to the millisecond level). Michiel From: [email protected]<mailto:[email protected]> [mailto:[email protected]<mailto:[email protected]>] On Behalf Of Jisha Mary Jose Sent: Thursday, July 10, 2014 11:18 To: Eric Decker Cc: Tinyos Help Request; Tinyos-Help Subject: Re: [Tinyos-help] random number I did that, i changed the seed. But still same numbers are generated again and again at a particular node. Regards, Jisha Mary Jose ......jMj...... On 10 July 2014 13:05, Eric Decker <[email protected]<mailto:[email protected]>> wrote: asked and answered. The random number generator is pseudo-random. It starts up using a SEED which you need to modify to get different sequences. On Wed, Jul 9, 2014 at 11:52 PM, Jisha Mary Jose <[email protected]<mailto:[email protected]>> wrote: Hi, I have to generate random number for a node to use in key generation. But i always get the same random number. So ichanged seed value using the current system time as shown below. module SecurityC{ uses interface Boot; uses interface Random; uses interface ParameterInit<uint16_t> as SeedInit; uses interface Timer<TMilli>; } implementation{ uint32_t rand1; uint32_t t; event void Timer.fired() { t=call Timer.getNow(); dbg("Boot", "%s Current time: %d \n", sim_time_string(), t); } event void Boot.booted() { dbg("Boot", "Application booted.\n"); t=call Timer.getNow(); call SeedInit.init(t); rand1 = (call Random.rand32()%10)+7; dbg("Boot", "%s Random number 1: %d \n", sim_time_string(), rand1); } } But still i am getting the same number always. How to solve this? Regards, Jisha Mary Jose ......jMj...... _______________________________________________ Tinyos-help mailing list [email protected]<mailto:[email protected]> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help -- Eric B. Decker Senior (over 50 :-) Researcher
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