Velocity Verlet¶

This NVE-ensemble integrator implements the velocity-Verlet algorithm in J. Chem. Phys. 76, 637 (1982).

The algorithm consists of a first half-step

$\vec{v}\Bigl(t + \frac{\tau}{2}\Bigr) &= \vec{v}\Bigl(t\Bigr) + \frac{\tau}{2} \frac{\vec{F}\left(t\right)}{m} \\ \vec{r}\Bigl(t + \tau\Bigr) &= \vec{r}\Bigl(t\Bigr) + \tau \vec{v}\Bigl(t + \frac{\tau}{2}\Bigr)$

and a second half-step

$\vec{v}\Bigl(t + \tau\Bigr) = \vec{v}\Bigl(t + \frac{\tau}{2}\Bigr) + \frac{\tau}{2} \frac{\vec{F}\left(t + \tau\right)}{m}$

class halmd.mdsim.integrators.verlet(args)¶

Construct velocity-Verlet integrator for given system of particles.

Parameters:	args (table) – keyword arguments args.particle – instance of `halmd.mdsim.particle` args.force – instance of `halmd.mdsim.forces` args.box – instance of `halmd.mdsim.box` args.timestep (number) – integration time step (defaults to `halmd.mdsim.clock.timestep`)

set_timestep(timestep)¶

Set integration time step in MD units.

Parameters:	timestep (number) – integration timestep

This method forwards to halmd.mdsim.clock.set_timestep(), to ensure that all integrators use an identical time step.

timestep¶: Integration time step in MD units.

disconnect()¶: Disconnect integrator from core and profiler.

integrate()¶

Calculate first half-step.

By default this function is connected to halmd.mdsim.core.on_integrate().

finalize()¶

Calculate second half-step.

By default this function is connected to halmd.mdsim.core.on_finalize().

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Velocity Verlet¶

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