Atom type

Dear all,

sorry for the stupid question but atom types have to be sobsequential ?

I mean in this example :
data file for lammps simulation

1316 atoms
1249 bonds
15 atom types
2 bond types
-102.82786854620527 102.82786854620527 xlo xhi
-102.82786854620527 102.82786854620527 ylo yhi
-102.82786854620527 102.82786854620527 zlo zhi

Masses

2 156.2
3 114.1
8 57.05
9 137.1
10 113.2
12 128.2
15 97.12
16 87.08
17 101.1
19 163.2
20 99.07
21 329.2
22 305.2
23 345.2
24 306.2

Atoms

1 1 23 -60.543900879749664 -67.82991736007715 -10.957878631050717
2 1 24 -58.349969856829084 -65.63598633715657 -8.763947608130138
3 1 23 -56.156038833908504 -63.442055314235986 -6.57001658520956

It gives me an error like “Invalid type for mass set”
That is because atom type has to go from 1 to 15 ?

Thanks
Daniele

All types from 1 to the max type must be defined and coefficients provided. That is a hard requirement. They may not all be used.

Many thanks