Package ffx.potential.nonbonded.pme

Class EwaldParameters

java.lang.Object
ffx.potential.nonbonded.pme.EwaldParameters
public class EwaldParameters extends Object
Mutable Particle Mesh Ewald constants.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    double
    aewald
     
    double
    aewald3
     
    double
    an0
     
    double
    an1
     
    double
    an2
     
    double
    an3
     
    double
    an4
     
    double
    an5
     
    static final double
    DEFAULT_EWALD_COEFFICIENT
    The default Ewald coefficient.
    static final double
    DEFAULT_EWALD_CUTOFF
    Default cutoff values for PME under periodic boundary conditions.
    double
    off
     
    double
    off2
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    EwaldParameters(double cutoff, double aewald)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static double
    ewaldCutoff(double coeff, double maxCutoff, double eps)
    Determine the Ewald real space cutoff given the Ewald coefficient and a target precision.
    void
    setEwaldParameters(double off, double aewald)
    Determine the real space Ewald parameters and permanent multipole self energy.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • DEFAULT_EWALD_CUTOFF

      public static final double DEFAULT_EWALD_CUTOFF
      Default cutoff values for PME under periodic boundary conditions.
      See Also:

    • DEFAULT_EWALD_COEFFICIENT

      public static final double DEFAULT_EWALD_COEFFICIENT
      The default Ewald coefficient.
      For charged systems, the converged Ewald electrostatic energy is a function of the Ewald coefficient. For this reason, we've chosen to use a default value of 0.545, for all real space Ewald cutoff values.
      In this way, systemically more accurate values for the real space cutoff, b-spline order and reciprocal space grid will converge the total electrostatic energy.
      See Also:

    • aewald

      @FFXProperty(name="ewald-alpha", propertyGroup=ParticleMeshEwald, defaultValue="0.545", description="Sets the value of the Ewald coefficient, which controls the width of the Gaussian screening charges during\nparticle mesh Ewald summation for multipole electrostatics. In the absence of the ewald-alpha keyword,\nthe default value is 0.545, which is appropriate for most applications.\n") public double aewald

    • aewald3

      public double aewald3

    • an0

      public double an0

    • an1

      public double an1

    • an2

      public double an2

    • an3

      public double an3

    • an4

      public double an4

    • an5

      public double an5

    • off

      public double off

    • off2

      public double off2

  • Constructor Details

    • EwaldParameters

      public EwaldParameters(double cutoff, double aewald)

  • Method Details

    • setEwaldParameters

      public void setEwaldParameters(double off, double aewald)
      Determine the real space Ewald parameters and permanent multipole self energy.
      Parameters:
      off - Real space cutoff.
      aewald - Ewald convergence parameter (0.0 turns off reciprocal space).

    • ewaldCutoff

      public static double ewaldCutoff(double coeff, double maxCutoff, double eps)
      Determine the Ewald real space cutoff given the Ewald coefficient and a target precision.
      Parameters:
      coeff - The Ewald coefficient in use.
      maxCutoff - The maximum cutoff.
      eps - The target precision.
      Returns:
      The determined real space Ewald cutoff.