[ODE] iterative solver: testing needed

[gl]

Just ran a quick test, throwing a bunch of spheres around my heightfield.
First impressions - wow.  In situations where loads of spheres are touching
one another (not as kinky as it sounds), the original solver usually kills
my renderer to below 1fps.  The iterative solver with the recommended 5
steps runs the same (i can't spot any visual differences), but at a
beautiful 50fps.  Way to go Dave!

I had a quick play with test_crash, and I see a problem where the buggy is
slowly moving right from the outset with Dave's solver, whilst it stops
completely with the original (as it should).  I can toggle between those
behaviours.  This is before any input has been applied.

Is this the problem you meant Dave?  It sounds like you were getting
spinning - of the car itself?  I'm not seeing that, just the wheels rotating
very slowly when it should be stationary.
--
gl

----- Original Message -----
From: "gl" <gl@ntlworld.com>
To: <ode@q12.org>
Cc: <david@csworkbench.com>
Sent: Sunday, March 30, 2003 10:43 AM
Subject: Re: [ODE] iterative solver: testing needed


>
> Small problem compiling the test on MS VC:
>
> ode/test/test_crash.cpp(205) : error C2086: 'i' : redefinition
>
> simply remove "int i" at line 172.
> --
> gl
>
>
> ----- Original Message -----
> From: <david@csworkbench.com>
> To: <ode@q12.org>
> Sent: Friday, March 28, 2003 3:32 PM
> Subject: [ODE] iterative solver: testing needed
>
>
> > Well guys, I need some help finding out why my car is spinning when it
> > stops in the iterative solver, so I'm releasing it for y'all to play
with.
> >  If you can help me define exactly what causes it, maybe I can track
down
> > my bug.  I think it has something to do with the contact constraint, but
> > I've tried all kinds of friction and slip parameters with both the LCP
and
> > my simpler solver (there's a define at the top of stepfast.cpp --
> > FAST_FACTOR or SLOW_LCP).  And I just can't seem to find anything that
> > makes it not spin (intuitively, the last thing I changed is what would
> > have caused it....)  So y'all give it a whirl and throw some ideas at
me.
> >
> > http://www.csworkbench.com/stepfast.zip
> >
> > Place that in the ode directory and extract it.  It will replace your
> > Makefile, Makefile.deps, and ode/include/objects.h files, as well as
> > placing the stepfast.h/cpp in the ode/src directory.  Then running make
> > should compile it in.  I've also put the test file I've been using
> > (test_crash.cpp) in the ode/test directory.  You'll notice lots of
defines
> > at the top.  You can change ROWS and COLS to a higher number to make the
> > army of cars, and uncomment #define WALL to add the box wall to the
> > simulation.  ITERS is the number of iterations per step.  You can press
> > 'f' during the simulation to switch back and forth between the iterative
> > solver and the old solver.  The green/red ball in the sky tells you
which
> > one you're using currently (green=iterative, red=old).
> >
> > So, play around with it, see if you can help me find my bug.  (Or just
> > play around with it :)  I'll continue testing and work on some
> > documentation.  If you want to use the iterative solver in a current
> > program of yours, just change:
> > dWorldStep(world, timestep);
> > to
> > dWorldStepFast(world, timestep, iterations);
> > 5 seems to be a generally good start for the number of iterations in the
> > tests I've run.  But more complex systems may need a higher number.
> >
> > Thanks for the help,
> > David Whittaker
> >
> >
> > _______________________________________________
> > ODE mailing list
> > ODE@q12.org
> > http://q12.org/mailman/listinfo/ode
> >
>
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