# Difference between revisions of "Beeman's algorithm"

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'''Beeman's algorithm''' <ref>[http://dx.doi.org/10.1016/0021-9991(76)90059-0 D. Beeman "Some multistep methods for use in molecular dynamics calculations", Journal of Computational Physics '''20''' pp. 130-139 (1976)]</ref> is is a method for [[Integrators for molecular dynamics |numerically integrating ordinary differential equations]], generally position and velocity, which is closely related to Verlet integration. | '''Beeman's algorithm''' <ref>[http://dx.doi.org/10.1016/0021-9991(76)90059-0 D. Beeman "Some multistep methods for use in molecular dynamics calculations", Journal of Computational Physics '''20''' pp. 130-139 (1976)]</ref> is is a method for [[Integrators for molecular dynamics |numerically integrating ordinary differential equations]], generally position and velocity, which is closely related to Verlet integration. | ||

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+ | In its standard form, it produces the same trajectories as the Verlet algorithm, but the velocities are more accurate: | ||

:<math>x(t+\Delta t) = x(t) + v(t) \Delta t + \left(\frac{2}{3}a(t) - \frac{1}{6} a(t - \Delta t) \right)\Delta t^2 + O( \Delta t^4) </math> | :<math>x(t+\Delta t) = x(t) + v(t) \Delta t + \left(\frac{2}{3}a(t) - \frac{1}{6} a(t - \Delta t) \right)\Delta t^2 + O( \Delta t^4) </math> |

## Latest revision as of 13:01, 19 April 2010

**Beeman's algorithm** ^{[1]} is is a method for numerically integrating ordinary differential equations, generally position and velocity, which is closely related to Verlet integration.

In its standard form, it produces the same trajectories as the Verlet algorithm, but the velocities are more accurate:

where *x* is the position, *v* is the velocity, *a* is the acceleration, *t* is time, and is the time-step.

A predictor-corrector variant is useful when the forces are velocity-dependent:

The velocities at time are then calculated from the positions.

The accelerations at time are then calculated from the positions and predicted velocities.