[Rd] problem with glm (PR#452)
Peter Dalgaard BSA
20 Feb 2000 13:30:07 +0100
Brad McNeney <firstname.lastname@example.org> writes:
> I'll see what I can do about getting a more reproducible error.
> Any tips on what to look for if I'm running R within GDB? I don't have
> much experience with the debugger. I mostly just use it to see where my
> programs are dying. But R is not -- it just gives strange error messages.
One technique is to set a breakpoint at the line that displays the
error, then you can inspect the condition that caused it (you may have
to go "up" a couple of times to get into an interesting environment.)
Sometimes, it turns out that a variable contains something that it
shouldn't due to memory corruption and then you may have to set a
breakpoint earlier in the code and then maybe a watchpoint on the
Another thing that is useful even without gdb is to investigate the
output of traceback() and maybe set
options(error=quote(DUMP <<- sys.status()))
which allows you to subsequently investigate any active environment at
the time of the error, e.g. using ls(envir=DUMP$sys.frames[]), and
(Newer snapshots have a more elaborate dump.frames function, but the
above should do).
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
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