[Ns-developers] ns-3.4 : Random Variables

[Raj Bhattacharjea]

The random variable tree here:
http://code.nsnam.org/raj/ns-3-rng-changes/

Has been proposed for merge.  In the process of preparing it for
merge, I became aware that it breaks the regression in ways I didn't
expect.  I've been trying to understand the changes it introduces to
the trace output, but I am hesitant to merge the tree until we can all
agree that the changes are well understood and sensible.

I apologize for delaying the merge while I fiddled with understanding
the issues, and for not addressing the list sooner.  The question I
have which remains is: are we sure that the changes to the RNG output
behavior that tree above introduces are consistent with the changes to
the seeding behavior?  Or, are there some subtle bugs?  I can't shake
the feeling that there is something fishy with the seeding behavior.
For example:

SeedManager::SetSeed(seeds) exists, and calls
RngStream::SetPackageSeed, which calls
RngStream::EnsureGlobalInitialized, which might recursively call
RngStream::SetPackageSeed with values read from the environment
variables (and different from what I passed into SeedManager::SetSeed
to begin with).  I am just plum puzzled by this behavior.

Also, should applying this changeset:
http://code.nsnam.org/raj/ns-3-rng-changes/rev/debf1a8a96d3
To the tip of ns-3-dev change the regression output?  Is it only for
the users of GetSingleValue?


-- 
Raj Bhattacharjea
Georgia Institute of Technology
School of Electrical and Computer Engineering
Ph.D. Candidate
Systems Analyst
404.894.2955