[ODE] SIGSEGV in dSolveLCP() at ode/src/lcp.cpp:1137

[Sergey Kurdakov]

Hello Olivier,

> I volunteer to implement this patch if it will be integrated into the 
> main ODE CVS trunk.

personally really thanks

 but one notion maybe as malloc/free could pose some run time overhead  then possibly  it worths a try to use 
some memory manager for ex 

http://www.geocities.com/wkaras/heapmm/heapmm.html ( public domain code)

at least maybe for some cases the speed will be faster.

Regards
Serge

----- Original Message ----- 
From: "Olivier Michel" <Olivier.Michel at cyberbotics.com>
Cc: "ode" <ode at q12.org>
Sent: Thursday, February 12, 2004 2:31 PM
Subject: Re: [ODE] SIGSEGV in dSolveLCP() at ode/src/lcp.cpp:1137


> Well, it works fine now. I patched the lcp.cpp file as follow:
> 
> #define ALLOCA(x) malloc(x)
> #define FREEA(a) free(x)
> 
> and I added a FREEA() for each ALLOCA() call in the source code. Now my 
> simulation never crashes (great!).
> We could do the same for other files (step.cpp, matrix.cpp, etc.) and 
> set up some #ifdef stuff so that the user can compile ODE in stack 
> allocation of dynamic allocation mode.
> 
> I volunteer to implement this patch if it will be integrated into the 
> main ODE CVS trunk.
> 
> Let me know what do you think about it.
> 
> -Olivier
> 
> 
> Olivier Michel wrote:
> 
> > Thanks for the replies. However, I cannot work around this problem:
> >
> > (1) I tryed increasing the heap size under Linux: "ulimit -s 
> > unlimited" to increase the heap size from 8192 to unlimited, but that 
> > didn't helped (might be ineffective).
> >
> > (2) I tryed to use dWorldStepFast1 instead of dWorldStep, but then all 
> > my bodies are falling down breaking the joints I set. I set all the 
> > masses to 1 to try to avoid this problem but it didn't change anything 
> > (still collapsing the model).
> >
> > It seems the simulation works with fine dSolveLCP() when the n 
> > parameter remains below ~200. However, when my two humanoid robots hit 
> > each other (~44 bodies connected through joints), n reaches 384 and 
> > the SIGSEGV occurs...
> >
> > I will try to replace all the ALLOCA from lcp.cpp to dynamical 
> > allocations / desallocations as it seems to be the only way to work 
> > around this problem, isn't it ?
> >
> > If it works, may I contribute this alternative to the ODE cvs if this 
> > is usefull for others ?
> >
> > -Olivier
> >
> > Martin C. Martin wrote:
> >
> >> Search the docs for "stack," and you'll see at least two things you 
> >> can do.
> >>
> >> - Martin
> >>
> >> Olivier Michel wrote:
> >>
> >>> Hi there,
> >>>
> >>> I have a bug in my ODE simulation which occurs in ODE dSolveLCP() 
> >>> function after a while and when two objects enter in collision, but 
> >>> I don't understand why a SIGSEGV occurs while creating a stack 
> >>> object in ode/src/lcp.cpp:1137. Here is what I get from gdb (under 
> >>> Linux/woody):
> >>>
> >>> Program received signal SIGSEGV, Segmentation fault.
> >>> [Switching to Thread 1024 (LWP 6180)]
> >>> 0x0817333e in dSolveLCP (n=351, A=0xbfef1630, x=0xbfeef480, 
> >>> b=0xbfeeff90,
> >>>   w=0xbfeee970, nub=0, lo=0xbfff9af0, hi=0xbfff8fe0, findex=0xbfff8a54)
> >>>   at ode/src/lcp.cpp:1137
> >>> 1137      dLCP lcp 
> >>> (n,nub,A,x,b,w,lo,hi,L,d,Dell,ell,delta_w,state,findex,p,C,Arows);
> >>>
> >>> How can the creation of a dLCP object cause a SIGSEGV ? Shall I try 
> >>> to replace it by something like:
> >>>
> >>> dLCP *lcp = new dLCP(...);
> >>>
> >>> Any hint would be appreciated.
> >>>
> >>> -Olivier
> >>
> >>
> > _______________________________________________
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> >
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