how to write the time correctly in lammps.

Dear Sir or Madam,
I want to define a function that changes over time, just like sin(t). But I don’t know how to write the time correctly in lammps.
Best regards
Liang

Checkout the Thermo_Style and Variable documentation pages:

https://lammps.sandia.gov/doc/thermo_style.html
https://lammps.sandia.gov/doc/variable.html