bad fisher.test() bug (PR#1662)
Thu, 13 Jun 2002 12:17:08 +0200 (MET DST)
(CC'ed to R-bugs ``for the record'')
>>>>> "BDR" == Prof Brian D Ripley <email@example.com> writes:
BDR> On Thu, 13 Jun 2002, Martin Maechler wrote:
>> >>>>> "MM" == Martin Maechler
>> <firstname.lastname@example.org> writes:
>> >>>>> "BDR" == Brian D Ripley <email@example.com>
BDR> Martin, What makes this a `bad bug'? Are you getting a
BDR> seg fault?
MM> yes, always in the half a dozen restarts I tried.
>> (in the mean time I had one case where it did not ..)
BDR> Like Uwe this works for me the first few times and I do
BDR> then get a backtrace (in memory.c, so this is almost
BDR> certainly an earlier overrun).
MM> I see. This has been different for me.
BDR> I think we've had problems before with FEXACT
BDR> incorrectly specifying the required sizes of its
>> (I'm not so sure this is the problem here.)
>> I found that
>> gives a direct segmentation fault (without any error
>> message) for me.
BDR> I've had to compile up gdb 5.2 to get the correct
BDR> information out of R on Linux compiled under gcc-3.1.
BDR> That shows (on the original problem)
BDR> Loaded symbols for
BDR> #0 f3xact (nrow=0x40051074, irow=0x4005113c,
BDR> ncol=0x40051000, icol=0x40051120, dlp=0x4041b110,
BDR> mm=0x40050fc0, fact=0x4035f020, ico=0x4035f4dc,
BDR> iro=0x4035f5a4, it=0x4035f66c, lb=0x4035f734,
BDR> nr=0x4035f7fc, nt=0x4035f8c4, nu=0x4035f98c,
BDR> itc=0x4035fa54, ist=0x40360094, stv=0x40364f18,
BDR> alen=0x40365ba0, tol=0x4004f878) at
BDR> 1125 ist[itp] = -1; (gdb) print itp $1 = -3544
BDR> The same with your variant (except the value of itp).
Okay, I found a much smaller table --- and a different place
for the seg.fault :
Program received signal SIGSEGV, Segmentation fault.
f2xact (nrow=0x8a12ec0, ncol=0x8a12ee0, table=0x8b7bb38, ldtabl=0x8a12f00,
expect=0x89dad68, percnt=0x89dad90, emin=0x89dadb8, prt=0x89dade0,
pre=0x89dae08, fact=0x403b3020, ico=0x403b302c, iro=0x403b3038,
kyy=0x403b3044, idif=0x403b3050, irn=0x403b3058, key=0x403b49d4,
ldkey=0xbfffc398, ipoin=0x403b5d44, stp=0x403b70b0, ldstp=0xbfffc39c,
ifrq=0x403ffef4, dlp=0x4046d450, dsp=0x4046fb30, tm=0x40472210,
key2=0x404748f4, iwk=0x403b3060, rwk=0x403b3d30)
524 obs += fact[ico[j]] - dd;
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