[lammps-users] Use of compute displace/atom in newest LAMMPS version.

Dear LAMMPS users,

I have been using a quite new version of LAMMPS (downloaded November 18, 2009), and have used these commands to compute the displacement of atoms relative to their original positions:

fix startpos all coord/original # Saves the inital particle positions as reference
compute disp all displace/atom startpos # Computes the displacement of each atom relative to the initial position

After downloading and making LAMMPS today (December 30, 2009), my script does not work anymore, and I wonder why.

I can see from the documentation online that the "fix coord/original" command has changed name to "fix store/coord", and that the whole command should be obsolete as the "compute displace/atom" command now invokes its own "fix store/coord". This means that my two input lines above should be replaced by one line like this:

compute disp all displace/atom

But when I try to run the input file, I get a message "ERROR: Invalid fix style".

Can anyone help me solving this problem?

Christer H. Ersland.

It's a bug. In compute_displace_atom.cpp, change the string
coord/original to store/coord. I'll post a patch for this,
but probably not until tomorrow.