sarkas.utilities.maths.force_error_approx_pm#

sarkas.utilities.maths.force_error_approx_pm(kappa, p, h, alpha)[source]#

Calculates the PM part of the force error, \(\Delta F_{\rm pm}\), for a given value of the PPPM parameters. The formula for \(\Delta F_{\rm pm}\) can be found in Force Error.

Parameters

  • kappa (float) – Inverse screening length.

  • p (int) – Charge assignment order.

  • h (float) – Distance between two mesh points. Same for all directions.

  • alpha (float) – Ewald screening parameter.

Returns

pm_force_error (float) – PM force error.