Bug 831 – Insufficient numerical precision of timestamped simulation time in the ascii trace file (ns-3.7)

Bug 831 - Insufficient numerical precision of timestamped simulation time in the ascii trace file (ns-3.7)


Summary:	Insufficient numerical precision of timestamped simulation time in the ascii ...

Status:	RESOLVED INVALID

Product:	ns-3
Classification:	Unclassified
Component:	core
Version:	ns-3.7
Hardware:	PC Linux

Importance:	P5 normal
Assigned To:	Craig Dowell

URL:
Keywords:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2010-03-03 18:36 UTC by Jakub Konka
Modified:	2010-05-16 18:25 UTC (History)
CC List:	2 users (show)

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Description Jakub Konka 2010-03-03 18:36:51 UTC

Overview:
The simulation time expressed in seconds and timestamped in the ascii trace file has insufficient numerical precision, and can cause erroneous results especially for high-speed wired data networks. 

Compare with bug 830 http://www.nsnam.org/bugzilla/﷒0﷓

The only difference between the two bugs is in the underlying NS3 modules: in ns-3-dev OutputStreamWrapper was responsible, in ns-3.7 AsciiWriter is.

In AsciiWriter module case, the bug can be fixed in exactly the same way as in OutputStreamWrapper (see bug 830 http://www.nsnam.org/bugzilla/﷒1﷓ ).

Comment 1 Craig Dowell 2010-04-07 14:45:49 UTC

With the new tracing framework, a user can set the floating point precision of the underlying stream to whatever is required.

  AsciiTraceHelper helper;
  Ptr<OutputStreamWrapper> stream = helper.CreateFileStream ("file");
  stream->GetStream ()->precision (8);

Does that meet your needs?