[petsc-users] floating point exception… but only when >4 cores are used...

[Sean Farley]

>> When I attach debugger on error on the local machine, I get a bunch of
>> lines like this one:
>>
>> warning: Could not find object file
>> "/private/tmp/homebrew-gcc-4.6.2-HNPr/gcc-4.6.2/build/x86_64-apple-darwin11.3.0/libstdc++-v3/src/../libsupc++/.libs/libsupc++convenience.a(cp-demangle.o)"
>> - no debug information available for "cp-demangle.c".
>
>
> It looks like you build with autotools. That just makes things hard :)

What? Matt, stop spreading misinformation; autotools has *nothing* to
do with this. You're on a mac and should know better.

Andrew, you get this warnings because the package system (homebrew, in
your case) didn't generate and save the debug symbols for gcc-4.6.2. I
have been trying to add this to MacPorts (but failed) and I might try
to do this with homebrew but until then, you'll have to do something
like the following:

1) tell homebrew to build and destroot gcc
2) manually go to the destroot directory (wherever that is) and run
dsymutil on all the .dylib files. A command to do that is `find
/path/to/destroot -name '*.dylib' -exec dsymutil {} +`
3) continue the homebrew installation (hoping that it picks up the *.dSYM files

Of course, you could just ignore the warnings :-)

As for the other problems, you might want to learn how to launch this
in gdb from the terminal.