[gmx-users] tpr file

[Mark Abraham]

> Dear GMX users,
>
> The following message is from a tpr file by gmxdump command:
>
> atom[  1111]={type=  4, typeB=  4, ptype=    Atom, m= 1.20110e+01,
> q=-5.29400e-01, mB= 1.20110e+01, qB=-5.29400e-01, resnr=   32}
> grpnrs=[ 0 0 0 0 0 0 0 0 0 0 ]}
>
> Could anyone tell me what does "type=  4" mean? I have checked the
> manual and mailing list, but no fortune to get the answer. Thank you for
> your help!

It's some kind of an atom type, which is an index into the list of atom
types actually used in your topology, which are sorted by earliest
occurrence in the atom list in the .top file. The .top / .tpr file pair I
compared to verify this had two different H atom types getting the same
value for type= as above. I couldn't work out the basis for this without
reading the code, I'm afraid. Numbering starts from zero, not one.

Mark