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Checksum (was : EGCG 9.0 and beyond)

Frederic PLEWNIAK plewniak at igbmc.u-strasbg.fr
Thu Mar 20 08:41:09 EST 1997


Jose R. Valverde wrote:
> 
> In article <5gpe92$c4c at acebo.sdi.uam.es>,

>> Wait a second! The ones that keep cksum do
>> finish in the last column! So that may be it, that last ~ Peter was
>> mentioning a while back? Hum...
>>
Perfectly right...
The checksum is calculated as follows :

 Checksum = (Sum for each pos of ((pos%57) * ASC(res[pos]))) % 10000
  
   where pos is position in sequence, and res[pos] is the residue
   at position pos (including gaps) and ASC(res[pos]) its ASCII 
   value.


Since the ASCII value is 46 for '.' and 126 for '~' it's no
wonder why sequences having gaps at the end do not have the
same checksum in GCG 9 (end-gaps '~') as in GCG 8 (end-gaps '.').
GCG 9 checksums are just perfectly normal.

Regards,

Fred



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