how to deal with the data file for three atom styles

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1

Hi everyone

I am puzzled at how to write the data file for read_data command. In my simulation, I need to use three atom styles: full, sphere and ellipsoid. As you see, both of sphere and ellipsoid particles need the density information. Under this condition, Should the density attribute written twice or just once? Can any one tell me which one is correct?
1: atom-ID atom-type x y z molecular-ID charge diameter density ellipsoidflag density
2: atom-ID atom-type x y z molecular-ID charge diameter density ellipsoidflag

Best regards

Yihua Zhou

2

Hi everyone

I am puzzled at how to write the data file for read_data command. In my
simulation, I need to use three atom styles: full, sphere and ellipsoid. As

you cannot have multiple atom styles in your input. you have to use
whatever is the superset of what you need, or create it using atom
style hybrid.

you see, both of sphere and ellipsoid particles need the density
information. Under this condition, Should the density attribute written
twice or just once? Can any one tell me which one is correct?
1: atom-ID atom-type x y z molecular-ID charge diameter density
ellipsoidflag density
2: atom-ID atom-type x y z molecular-ID charge diameter density
ellipsoidflag

all lines have to follow the same format. the read_data documentation
explains how to handle hybrid styles.

i strongly suggest to build some small test systems with only two
variants and see, if you can build a correctly working setup with
these. for some combination of atom styles this may not be
straightforward.

axel.

3

Hi everyone

I am puzzled at how to write the data file for read_data command. In my
simulation, I need to use three atom styles: full, sphere and ellipsoid. As
you see, both of sphere and ellipsoid particles need the density
information. Under this condition, Should the density attribute written
twice or just once? Can any one tell me which one is correct?
1: atom-ID atom-type x y z molecular-ID charge diameter density
ellipsoidflag density
2: atom-ID atom-type x y z molecular-ID charge diameter density
ellipsoidflag

all lines have to follow the same format. the read_data documentation
explains how to handle hybrid styles.

"Note that if a non-standard value is defined by multiple sub-styles,
it must appear mutliple times in the atom line. E.g. the atom line for
atom_style hybrid dipole full would list "q" twice:

atom-ID atom-type x y z q mux muy myz molecule-ID q"

http://lammps.sandia.gov/doc/read_data.html

So it looks like #1 is the correct choice. (assuming atom_style
hybrid full sphere ellipsoid)

(Thanks Axel. I was too lazy to look this up until you pointed it
out. But I was curious about this topic too.)

4

An ellipsoid can be a sphere, so you probably only need

two atoms styles. And as Axel said, you need to use
atom_style hybrid to do that.

Steve