question about warning message

[Andreas Stolcke]

Sarah,

there are differences in floating point arithmetic between Sparc and Intel
CPUs, but it looks like something else is going on.  Please send me the 
input data (just the counts would be enough) and how exactly you invoke
ngram-count and I'll try to figure it out.  I might be a good-old-fashioned
bug ...

--Andreas

In message <Pine.LNX.4.21.0105231331160.3828-100000 at titanium.cs.washington.edu>
you wrote:
> hi all,
> 
> I am running SRILM 1.0.1 on two different platforms (linux and
> solaris) and got different results using the same data with exactly the
> same commands.  I'm hoping that someone else might have some insight...  
> 
> I'm not doing anything fancy - in this case, I just used ngram-count to
> build a trigram lm using the default settings for GT discounting, etc.  
> Still, I get noticably different results ( ppl= 18.0975 ppl1= 40.7525 in
> linux and  ppl= 17.2411 ppl1= 38.3 in solaris )
> 
> The solaris version gives the following warning, but the linux version
> does not:
>  warning: discount coeff 1 is out of range: 0.900585
> 
> I turned on the -debug 3 flag to get more information, and the output of
> the two versions are nearly identical.  The differences are the warning
> above, also, one verision discards 1 1-gram prob prdeicting a pseudo-event
> while the other discards 2, and in the end, they have very different
> left-over probability masses ( 0.00388768 vs.  4.55956e-06, where the
> second number corresponds with the warning I quoted above )
> although they distribute these over the same number of
> unseen events and write the same number of n-grams.  The GT-count numbers
> are also all the same in both versions.
> 
> I found the warning message in the code (in lm/src/Discount.cc) but I
> don't really understand what's causing it, and I certainly don't
> understand why I get it on one installation and not the other.  If anyone
> has any insight to offer, I'd greatly appreciate it. 
> 
> thanks much,
> Sarah
> 
> ________________________
> Sarah Schwarm
> sarahs at cs.washington.edu
>