Error : Expected integer parameter in input script or data file

Hello Everyone,

I’ve been working on “MD simulation of Nano Indentation of CNT reinforced polymer”.

Got an error like "Expected integer parameter in input script or data file ".

I’ve gone through all Lammps mailing list and manual, and then understand that “need to change floating point to integer”. But my input file is very big and little difficult to change(edit) all values (angles, dihedrals) and alsoi don’t have much time to start my simulation from starting since my it is taking long time (~8 days).

Is there any other way to fix this error?

Attaching file (restart) for further details.

Thank in advance

Ashok Kumar Bevara

Hello Everyone,

I've been working on "MD simulation of Nano Indentation of CNT reinforced
polymer".

Got an error like "Expected integer parameter in input script or data
file ".

I've gone through all Lammps mailing list and manual, and then understand
that "need to change floating point to integer". But my input file is very
big and little difficult to change(edit) all values (angles, dihedrals) and
alsoi don't have much time to start my simulation from starting since my it
is taking long time (~8 days).

​8 days is not a long time for a simulation. who says that you need to
change *all* values. first of all, you have to determine *where* in the
input exactly this error happens.​

Is there any other way to fix this error?

​this error typically happens, when your input is incorrect and you cannot
make a simulation run correctly with incorrect input.

Dr. Axel,

Thanks for reply!

I agree with you 8 days is not a long time but problem is I have to submit my results by oct 31st.(4 more days left)

And
These are the exact lines where error occured:

fix 1 all nvt temp 600.0 600.0 5 drag 1.5
fix 4 all bond/create 100 9 7 3.0 15 iparam 5 itype
ERROR: Expected integer parameter in input script or data file (…/fix_bond_create.cpp:87)

please help me to clear this error.

Thanks in advance

Ashok Kumar Bevara

Based on the documentation (http://lammps.sandia.gov/doc/fix_bond_create.html), it seems that the “iparam” keyword expects two numbers. You supplied one. This is why LAMMPS says “Expected integer parameter”. Furthermore, “itype” is also a keyword that needs one argument.

Mr. Stefan,

In that documentation its mentioned " If you do not wish the atom type to change, simply specify newtype as itype or jtype."

as you suggested just tried with itype arg as “none” bt still same error

fix 1 all nvt temp 600.0 600.0 5 drag 1.5
fix 4 all bond/create 100 9 7 3.0 15 iparam 5 itype none
ERROR: Expected integer parameter in input script or data file (…/fix_bond_create.cpp:87)

Actually, i’m using this keyword iparam which can limit the bonding functionality of the participating atoms to clear “error:New bond exceeded bonds per atom in fix bond/create”.

Thanks in advance,

Ashok Kumar Bevara

I don’t know if it is supposed to work like you think it is, from the default options I am inclined to think maybe it is. I have never used fix bond/create.

However, as a work-around, can’t you just replace the “newtype” part of the keyword with the actual value you supply for “itype” in the fix. So in your case it should become
“fix 4 all bond/create 100 9 7 3.0 15 iparam 5 9”
because the itype you supply is also 9. The itype keyword has to do with impropers, I am not sure if you want that.

Hi Mr. Stefan (and All),

I did use
“fix 4 all bond/create 100 9 7 3.0 15 iparam 5 9”
but i got an error like
Error: Special list size exceeded in fix bond/create
which i didn’t find in LAMMPS mailing list

and i have been using speial size with “extra 3” keyword.

plz check the attached file (in the first mail) for further details.