hdb documentation error
In the GROMACS 4 manual on page numbered 103, in the list of hydrogen database types, type 6 refers to a pair of hydrogen atoms built from an aliphatic C and its two heavy-atom neighbours.
"6 two tetrahedral hydrogens, e.g. C-CH2 -C
two hydrogen atoms (n1,n2) are generated at a distance of 0.1 nm from atom i in
tetrahedral conformation on the plane bissecting angle i-j-k with angle (n-i-n2)=(n1-i-j)=(n1-i-k)=109.5"
doesn't seem to describe the process correctly. If the H atoms are indeed built near atom i, then they should be "on the plane bisecting angle j-i-k" (spelling and ordering errors) and I think the first angle equal to 109.5 degrees should be "(n1-i-n2)".
Alternatively, if the atoms are actually built near atom j, then the i-j-k angle bit is right and all three angles equal to 109.5 degrees are mis-labelled.
I tried to see which way it is, but got rapidly lost in the hackblock nightmare :-)
The wording is still incorrect in git manual, though I happen to have fixed the spelling error during some recent house-keeping.