[ODE] ODE debugging dSolveLCP

[Marcello Cirillo]

Hi.

I'm a new subscriber and I have some problems that I hope somebody could 
solve.

I was doing some memory debugging with valgrind on my program, and I've 
got a strange warning / error coming from a ODE library.

Could somebody please explain me if it's a really dangerous problem? It 
seems to come from the dSolveLCP function.
I attach the lines I received from valgrind and GDB.

Thanks
M.


Valgrind Output during normal execution (no segmentation fault yet):

==21128== Use of uninitialised value of size 8
==21128==    at 0x80AA15D: swapProblem(double**, double*, double*, 
double*, double*, double*, int*, int*, int*, int, int, int, int, int) 
(lcp.cpp:240)
==21128==    by 0x80AAA6C: dLCP::dLCP(int, int, double*, double*, 
double*, double*, double*, double*, double*, double*, double*, double*, 
double*, int*, int*, int*, int*, double**) (lcp.cpp:792)
==21128==    by 0x80AC3CF: dSolveLCP(int, double*, double*, double*, 
double*, int, double*, double*, int*) (lcp.cpp:1137)
==21128==    by 0x80A5CD8: dInternalStepIsland_x2(dxWorld*, dxBody* 
const*, int, dxJoint* const*, int, double) (step.cpp:835)

The problem recognised by valgrind is then passed to gdb, that gives the 
following lines:

0x080aa15d in swapProblem (A=0x52be9830, x=0x52bf14e0, b=0x52bf16d0, 
w=0x52bf12f0, lo=0x52bfc800, hi=0x52bfc610, p=0x52be9730, state=0x52be9530,
     findex=0x52bfc514, n=59, i1=5, i2=6, nskip=60, do_fast_row_swaps=0) 
at ode/src/lcp.cpp:240
240       tmp = w[i1];





When a Segmentation Fault occurs in my program, most of the time this is 
the gdb output:

#0  0x080ac35f in dSolveLCP(int, double*, double*, double*, double*, 
int, double*, double*, int*) (n=353, A=0xbfeeced0, x=0xbfeeae00, 
b=0xbfeeb920,
     w=0xbfeea2e0, nub=15, lo=0xbfff97d0, hi=0xbfff8cb0, 
findex=0xbfff8714) 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);

#1  0x080a5cf1 in dInternalStepIsland_x2(dxWorld*, dxBody* const*, int, 
dxJoint* const*, int, double) (world=0x8146890, body=0xbffff030, nb=42,
     _joint=0xbfffebd0, nj=85, stepsize=0.0025000000000000001) at 
ode/src/step.cpp:835
835         dSolveLCP (m,A,lambda,rhs,residual,nub,lo,hi,findex);