Re: Time precision

[Yuri Pryadkin <yuri@who.isi.edu>]

It's been fixed.  Thanks!

 -Yuri

Pablo Molinero Fernandez <molinero@stanford.edu> writes:

> Hi Massimo,
> 
> I agree with you. I think that in the next ns release they should maintain
> the precission of the traces throughout the simulation. It is a simple
> matter of changing lines 255 and 276 in ns-2/ns-2/trace.cc from:
> 
> sprintf(wrk_, "%c %g %d %d %s %d %s %d %s%s %s%s %d %d",
> 
> to:
> 
> sprintf(wrk_, "%c %.9g %d %d %s %d %s %d %s%s %s%s %d %d",
> 
> or:
> 
> sprintf(wrk_, "%c %.9f %d %d %s %d %s %d %s%s %s%s %d %d",
> 
> Pablo
> 
> On Tue, 15 Jun 1999, Massimo Pegorer - Stage wrote:
> 
> > Running some simulations I've noticed that time in ns output files is
> > always given with the six most significant digits, and this fact gives
> > me some problems in postprocessing these files because of the rounding;
> > for example, when the time goes beyond 100 seconds, fractions of msec
> > are lost:
> > 
> > [...]
> > - 99.9961 0 1 cbr 1000 ------- 0 0.0 1.0 19803 19803
> > r 99.9962 0 1 cbr 1000 ------- 0 0.0 1.0 19801 19801
> > r 100.001 0 1 cbr 1000 ------- 0 0.0 1.0 19802 19802
> > + 100.003 0 1 cbr 1000 ------- 0 0.0 1.0 19804 19804
> > [...]
> > 
> > This has curious consequences for nam, too. For absurde, if you have a
> > cbr flow with 5ms interval time between packets (interval_=0.005) and it
> > starts at 1000, packets #0 and #1 will have the same start-time (1000)
> > and nam will visualize only packet #1 and not #0!
> > 
> > + 1000 0 1 cbr 1000 ------- 0 0.0 1.0 0 0
> > - 1000 0 1 cbr 1000 ------- 0 0.0 1.0 0 0
> > + 1000 0 1 cbr 1000 ------- 0 0.0 1.0 1 1
> > - 1000 0 1 cbr 1000 ------- 0 0.0 1.0 1 1
> > + 1000.01 0 1 cbr 1000 ------- 0 0.0 1.0 2 2
> > - 1000.01 0 1 cbr 1000 ------- 0 0.0 1.0 2 2
> > r 1000.01 0 1 cbr 1000 ------- 0 0.0 1.0 0 0
> > + 1000.01 0 1 cbr 1000 ------- 0 0.0 1.0 3 3
> > - 1000.01 0 1 cbr 1000 ------- 0 0.0 1.0 3 3
> > r 1000.01 0 1 cbr 1000 ------- 0 0.0 1.0 1 1
> > r 1000.02 0 1 cbr 1000 ------- 0 0.0 1.0 2 2
> > [...]
> > 
> > I think this depends on sprintf %g default precisions (in
> > Trace::format), but in my opinion it would be more useful to have always
> > time with the same format and with six digits after the decimal-point
> > (microsec), such as with %f.
> > I hope not to have annoyed you with tedious questions. Thanks for
> > suggest.
> > 
> > max
> > 
> > 
> > --
> > Massimo Pegorer, student
> > Dipartimento di Elettronica e Informatica
> > Universita' degli Studi di Padova
> > Padova - ITALIA
> > 
> > 
> 
> -------------------------------------------------
> Pablo Molinero Fern�ndez
> (650) 497-7490 (home)
> (650) 723-1414 (office)
> http://www.stanford.edu/~molinero
> Snail-mail:  Gates Building 3A, Room 342
>              Stanford, CA 94305-9030