Package ffx.potential.bonded

Interface LambdaInterface

All Known Implementing Classes:
AngleTorsion, ANIEnergy, COMRestraint, DualTopologyEnergy, ForceFieldEnergy, GeneralizedKirkwood, NCSRestraint, OpenMMEnergy, OrthogonalSpaceTempering, ParticleMeshEwald, PiOrbitalTorsion, QuadTopologyEnergy, RealSpaceEnergy, RefinementEnergy, RestrainDistance, RestrainPosition, RestraintTorsion, StretchTorsion, Torsion, TorsionTorsion, VanDerWaals, VanDerWaalsTornado, XRayEnergy
public interface LambdaInterface
The LambdaInterface should be implemented by potential energy terms that can accept a lambda value from [0 .. 1] that defines a twice differentiable path between states 0 and 1.
Since:
1.0
Author:
Michael J. Schnieders

  • Method Summary

    Modifier and Type
    Method
    Description
    default boolean
    dEdLZeroAtEnds()
    Returns true if dUdL is guaranteed to be zero at 0 and 1.
    double
    getd2EdL2()
    Get the 2nd partial derivative of the energy with respect to lambda.
    double
    getdEdL()
    Get the partial derivative of the energy with respect to lambda.
    void
    getdEdXdL(double[] gradient)
    Get the gradient of dEdL with respect to each parameter.
    double
    getLambda()
    Get the current value of the state variable.
    void
    setLambda(double lambda)
    Set the current value of the state variable.

  • Method Details

    • dEdLZeroAtEnds

      default boolean dEdLZeroAtEnds()
      Returns true if dUdL is guaranteed to be zero at 0 and 1. Default implementation is to return false.
      Returns:
      True if dUdL is guaranteed 0 at endpoints.

    • getLambda

      double getLambda()
      Get the current value of the state variable.
      Returns:
      state
      Since:
      1.0

    • setLambda

      void setLambda(double lambda)
      Set the current value of the state variable. May be ignored if lambda is not being applied.
      Parameters:
      lambda - a double.
      Since:
      1.0

    • getd2EdL2

      double getd2EdL2()
      Get the 2nd partial derivative of the energy with respect to lambda.
      Returns:
      d2EdL2
      Since:
      1.0

    • getdEdL

      double getdEdL()
      Get the partial derivative of the energy with respect to lambda.
      Returns:
      dEdL
      Since:
      1.0

    • getdEdXdL

      void getdEdXdL(double[] gradient)
      Get the gradient of dEdL with respect to each parameter.
      Parameters:
      gradient - - A double array of length the number of parameters in the model (commonly 3 * number of atoms).
      Since:
      1.0