Thank you very much!
i fixed that problem in my input file.then i got another problem, this time
error says:
Neighbor list overflow, boost neigh_modify one or page (neigh_full.cpp:426)
i read the manual and the mail lists, but since this is my first job with
lammps may be, things did not make quite sense...how can i decide in my
if this is your first calculation with lammps, i strongly suggest that
you start by setting up a simple system from scratch and play with
the examples. trying to make a complicated system work as the
first lammps job is self-inflicted torture. it is much better to learn
the basic do's and don'ts with a system that you know about rather
than being constantly in the dark about whether something makes
sense or not. please keep in mind, that a successfully run trajectory
in classical MD is not necessarily a meaningful one. there are
a bit of skill and practical experience needed to choose parameters
wisely and to get to know how a specific MD code works.
you are currently making your life miserable without need.
system what is the suitable neighbor page size or maximum number of
neighbors allowed for one atom?what is the meaning of " page size must be >=
10x the one atom setting "?Could you please make those a little bit more
clear?
this is a very technical issue and you are most welcome to submit
a better wording for the explanation, after you have worked out what
went wrong. i personally find the text in the neigh_modify documentation
very to the point and helpful.
"The page and one options affect how memory is allocated for the
neighbor lists. For most simulations the default settings for these
options are fine, but if a very large problem is being run or a very
long cutoff is being used, these parameters can be tuned. The indices
of neighboring atoms are stored in "pages", which are allocated one
after another as they fill up. The size of each page is set by the
page value. A new page is allocated when the next atom's neighbors
could potentially overflow the list. This threshold is set by the one
value which tells LAMMPS the maximum number of neighbor's one atom can
have."
the translation is: that "one" is the estimate for the largest amount of
storage a single atom may need for its neighbor list. if an atom has
more neighbors, it may silently corrupt the neighbor lists. and "page"
is a measure for the size of a single block of memory (or page or tile)
that is allocated in one step for storing neighbors. the larger page is
relative to one, the more efficiently the neighbor lists can be packed
together, but if page is too large, memory will be wasted, too.
so neighborlist overflow happens, when you have too many neighbors
for a single atom. LAMMPS uses a per-job fixed limit for this, in
order to be more efficient. rather than simply silencing the error,
you should wonder, whether there is a good reason to have so many
neighbors. the default settings are well suited for all, but a select
few calculations with very small particles relative to their cutoff
radius, or simulations at high pressure.
you should first check your input and see, if the choices for
cutoffs are reasonable and that the distances between atoms
make sense, too. if they are off, then increasing the neighbor
list storage will only postpone the inevitable crash due to bad
dynamics of your system later.
that being said, if this large number of neighbors is indeed expected,
you can change the value of "one" to something larger and then
change the value for "page" accordingly.
cheers,
axel.