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#137 floating point error in math.atan2()

Done
nobody
Low
2018-09-30
2010-06-02
Anonymous
No

Originally created by: aeitsch...@yahoo.de

What steps will reproduce the problem?
1.On some Linux-systems just start the Bell UH1

What is the expected output? What do you see instead?
The Bell UH1 should work without any problems. Instead on some Linux-
systems the heli begins to start shaking violently and finally crashing
FlightGear producing a lot of NaN-Errors and  error-message:

Nasal runtime error: floating point error in math.atan2()
  at /usr/share/FlightGear-2.0.0/Aircraft/UH-1/Nasal/uh1.nas, line 15
  called from: /usr/share/FlightGear-2.0.0/Aircraft/UH-1/Nasal/uh1.nas,
line 228
  called from: /usr/share/FlightGear-2.0.0/Aircraft/UH-1/Nasal/uh1.nas,
line 245
  called from: /usr/share/FlightGear-2.0.0/Aircraft/UH-1/Nasal/uh1.nas,
line 387

This won't happen on win32-systems.

What version of the product are you using? On what operating system?
The latest from GIT or Helijah's page.

Ubuntu Lucid (10.04) built with OSG 2.6.8 and simgear 2.0. as an example.
Some other Linux distribution as well

Please provide any additional information below.
http://www.flightgear.org/forums/viewtopic.php?f=25&t=8229&start=15#p81449

http://www.youtube.com/watch?v=W7VITyX7Gak

Discussion

  • Anonymous

    Anonymous - 2010-10-19

    Originally posted by: anders.g... (code.google.com)@gmail.com

    This could be due to subtle differences between floating point arithmetic using 387 or SSE instructions (or even optimization level).
    I know that at one point a certain YASim aircraft would only converge on my system with
    -mfpmath=sse in the CXXFLAGS and not with -mfpmath=387 (which IIRC was the default for my build).

    Labels: Aircraft YASim

     
  • Anonymous

    Anonymous - 2011-05-25

    Originally posted by: cumuluni... (code.google.com)@gmail.com

    Is this still an issue?

    Labels: Priority-Low
    Status: Stalled

     
  • Anonymous

    Anonymous - 2011-07-18

    Originally posted by: cumuluni... (code.google.com)@gmail.com

    Not an issue on my 64bit Linux. Can we close this?

     
  • Anonymous

    Anonymous - 2011-07-18

    Originally posted by: bre... (code.google.com)@gmail.com

    May be related to issue #256, which was fixed some weeks ago and affected 32bit Linux systems with recent compilers (causing NaNs and lot's of subtle issues). Closing this issue now, since there was no feedback since it stalled in May. If anyone still sees this, please "reopen" - or file a new report.

    Status: Expired

     

    Related

    Tickets: #256

  • xDraconian

    xDraconian - 2018-09-30
    • Status: Expired --> Done
     

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