How to change the VCS random seed

[jammed]

When running VCS, the default seed for RNG is 1.
ex:
% vcs -R -sverilog my_test.sv

If I run this many times I will always get the same simulation results.


How do I change the random seed, so that if I run my_test many times, i get different simulation results from different seeds?
Is there a compile-time/run-time option that can change the seed value?
ex:
% vcs -R -sverilog <option_for_specifying_random_seed> my_test.sv

 

[aji_vlsi]

ntb_random_seed

When running VCS, the default seed for RNG is 1.
ex:
% vcs -R -sverilog my_test.sv

Try:

+ntb_random_seed=<number>

If you have a PERL/Shell script around your vcs, then it is quite easy to generate a random number and pass it to vcs.

HTH
Ajeetha
www.noveldv.com

 

[jammed]

vcs random seed

thanks aji for your suggestion.

actually i have already tried that before, but somehow i can't get it to work.
do you have a working example?

anyway, i have figured out a way of doing it, using $value$plusargs("seed=%d",seed)

from the command line, i can use :
%simv +seed=<value>

and yes, i generate the value using a script, so it really is random now everytime i run it. =)

cheers.

 

[sudhamahesh70]

Re: VCS random seed

use this command after compilation

./simv +ntb_random_seed=value

Its working for me.

--Mahesh