[gmx-users] a query....
Mark.Abraham at anu.edu.au
Tue Jan 31 13:44:07 CET 2006
Xavier Periole wrote:
>> This is what I got after typing "1 & 2"
>> Copied index group 1 'group1'
>> Copied index group 2 'group2'
>> Merged two groups with AND: 635 637 -> 0
>> Group is empty
> here says the group is empty !!! Which is why there is zero !!!
> the two groups have just no atoms in common !!! If you want to merge
> you got to use pipe "|"
It's Boolean logic applied to sets. "&" is the intersection operator,
"|" is the union operator.
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