[SRILM User List] Does the calculation of Back Off Weight use the special property of different Discount?

[Andreas Stolcke]

On 3/4/2014 2:31 AM, Junfei Guo wrote:
> Hi All,
>
> From the source code I can see that to calculate the Lower Oder Weight 
> for interpolation, Srilm uses the special properties of different 
> Discount function. For example for Modified KN, it uses the fact that 
> the discount is a constant for all trigrams which shows up more than 3 
> times.
>
> My question is weather the calculation of Back Off Weight also use 
> this sort of information or it only assume a general discount function.

The computation of backoff weights if independent of discounting 
method.  It is only determined by the requirement that the sum of all 
probabilities for a given history sum up to 1.

Andreas


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