Re: Debugging stochastic programs
- From: "AN O'Nymous" <a_n_onymous80@xxxxxxxxxxx>
- Date: 23 Jan 2006 04:40:13 -0800
Dr Ivan D. Reid wrote:
> But are you starting with the same seeeding each time?
Yes. I will try to leave running two separate runs with exactly the
same input & database files. The database files were slightly different
for both runs where the sigsegv occurred, and I suppose if the number
of random calls was off by just 1, the seeds differ after that.
> Turn on bounds checking, and look very carefully for mismatched
> sub-program parameters (esp. if sections are compiled separately).
It is one program compiled as a whole, using Intel FC 8.0 for Linux.
How do I turn on bounds checking?
> Are you overflowing an accumulated sum (tho' that's not likely to
> directly cause a sigsegv, I think)?
I don't think so. I haven't noticed this bug with other runs of similar
size. I'm guessing a specific random generated number that is causing
problems with the code is somehow responsible.
I don't have such a line in my code but an example of what I'm saying
temp = 1.0/random
The above code would be fine for all values except for a particular
random value of 0.
How do people normally debug a stochastic program that only crashes
after 1 day and is otherwise fine in 99.9% of the other runs?