How Fuzzy score and Score() function works in HANA?

Hi,

I read fuzzy developer guide of HANA, but i am not getting how HANA calculate score() and fuzzy score?

As per developer guide, Score() is calculate using TF/IDF, and I also try to calculate TF/IDF as per WIKI page, but it gives different values. and Score() value is changed as per x value of fuzzy(x) .

See example

select score() as sc, *

from COMPANIES2

where contains(Companyname,'IBM',fuzzy(0.7))

it returns

SC;                             ID; COMPANYNAME;  CONTACT

0.7599999904632568;   6;  IBM Corp;               M. Master

and for

select score() as sc, *

from COMPANIES2

where contains(Companyname,'IBM',fuzzy(0.2))

it return

SC;                               ID;  COMPANYNAME;       CONTACT

0.16945946216583252;   2;   SAP in Walldorf Corp;  Master Mister

0.8392000198364258;     6;   IBM Corp;                   M. Master

and table content of Companies2 is

ID; Companyname;           contact

1;  SAP Corp;                   Mister Master

2;  SAP in Walldorf Corp;   Master Mister

3;  ASAP;                         Nister Naster

4;  ASAP Corp;                 Mixter Maxter

5;  BSAP orp;                   Imster Marter

6;  IBM Corp;                    M. Master

Please provide any formula or algorithm for above.

Thanks,

Somnath A. Kadam