[ODE] floats/doubles

Tobias Thorsen tobias at chaseace.com
Wed Feb 12 15:07:02 2003


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Hi ODE list

Ive implemented ode into a rudimentary engine i created, and i just used =
the default settings for a while with double prescision. So now i wanted =
to test how much performance i would get when compiling with single =
prescision instead. But the problem is that it simply doesnt run =
anymore. I dont do any "illegal" conversions between my internal numbers =
and dReals. Only an occational pos.x =3D (float) pos[0] and simple stuff =
like that.
I know the problem can be anywhere in my program and might not have =
anything to do with ODE, but has anyone experienced similar problems?
I get some warnings when i compile, but none that i would consider =
dangerous.

My app seems to start up, and runs very slow using a LOT of time in the =
ODE simulate code. 25ms or more.  (it ran less than 8 in double =
prescision mode) (800mhz pIII). All my models are gone (probably off to =
infinity) and the program seems to crash on the strangest places where =
it really shouldnt crash.

Any ideas?

Thanks.
Tobias Thorsen
www.spacetimefoam.com


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<DIV><FONT face=3DArial size=3D2>Hi ODE list</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>Ive implemented ode into a rudimentary =
engine i=20
created, and i just used the default settings for a while with double=20
prescision. So now i wanted to test how much performance i would get =
when=20
compiling with single prescision instead. But the problem is that it =
simply=20
doesnt run anymore. I dont do any "illegal" conversions between&nbsp;my =
internal=20
numbers and dReals. Only an occational pos.x =3D (float) pos[0] and =
simple stuff=20
like that.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I know the problem can be anywhere in =
my=20
program&nbsp;and might not have anything to do with ODE, but has anyone=20
experienced similar problems?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I get some warnings when i compile, but =
none that i=20
would consider&nbsp;dangerous.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>My app seems to start up, and runs very =
slow using=20
a LOT of time in the ODE simulate code. 25ms or more.&nbsp; (it ran less =

than&nbsp;8 in double prescision mode) (800mhz pIII). All my models are =
gone=20
(probably off to infinity) and the program seems to crash on the =
strangest=20
places where it really shouldnt crash.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>Any ideas?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>Thanks.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Tobias Thorsen</FONT></DIV>
<DIV><FONT face=3DArial size=3D2><A=20
href=3D"http://www.spacetimefoam.com">www.spacetimefoam.com</A></FONT></D=
IV>
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