Dear All,

I am using LAMMPS (14 Feb 2014) and have some questions ：

1.In the example of elastic constant calculation，there is such a command in init.mod：

# Need to set mass to something, just to satisfy LAMMPS

mass 1 1.0e-20

However，1.0e-20 isn’t the mass of ‘Si’ applied in the example.What does it mean?How to explain

‘# Need to set mass to something, just to satisfy LAMMPS’?

2.If the model has 3 types of atoms，should I use this command for 3 times?

mass 1 1.0e-20

mass 2 1.0e-20

mass 3 1.0e-20

3.The example calculates elastic constants in 0K,right?I just wonder whether the example could calculate elastic constants in higher temperature,such as 300K?If no,how to realize it?

Thank you very much for your answer