Re: [OpenSTA-devel] Re: When is Random not random?

[Mark E. <ma...@bo...>]

Daniel Sutcliffe wrote:
> Peter Wickersham wrote:
>>So, I looked at the source and the code appears to use srand()
>>everytime it calls rand() with the last result from calling rand().
>>However, this actually ends up producing more collisions more
>>quickly than just calling srand() once. 
> 
> 
> Can you give us a source file and line number to save me a little bit
> of work?  I'm only just getting into the inner workings of SCL - the
> previous SCL internals expert no longer has time to give to this 
> project.
> 

This will be the variable handling at runtime, in both CECRangeVar.cpp 
and CECListVar.cpp. The seed generated at the start of the variable use 
should bring in a semi random element (see comments in 
CECVar::GetRandomSeed()). Obviously not enough :-) Can't remember if the 
options passed at variable contruction will allow a runtime descision as 
to if this is REPEATABLE RANDOM or not though. Can probably have a look 
later if no one else gets a chance.

Mark