Where in the source is the math for verlet (default) integration?

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1

Hi all,

I’ve looked in several source code files and haven’t been able to find what looks like

x[i] = x[i] + v[i]dt + 0.5a[i]dtdt;

I’ve checked verlet.cpp, integrate.cpp and other files to no avail.

Please assist!

2

Hi all,

I've looked in several source code files and haven't been able to find what looks like

x[i] = x[i] + v[i]*dt + 0.5*a[i]*dt*dt;

I've checked verlet.cpp, integrate.cpp and other files to no avail.

please try fix_nve.cpp

verlet only determines the "hooks" where the various time integration
steps can happen. those are then offloaded to fix styles, since LAMMPS
allows different ways to do time integration. nearly all fix styles
that provide the methods "initial_integrate()" and "final_integrate()"
can do some form of time integration and can be applied to all or a
subset of atoms.

fix nve provides plain velocity verlet time integration.

HTH,

   axel.

3

It’s in fix_nve.{cpp,h} or other fixes that perform time integration.

4

Excellent, ty all