Struct Harm 

pub struct Harm<T> { /* private fields */ }

Harmonic improper torsion potential.

Parameters

• k: Force constant (energy/radian² units)
• xi0: Equilibrium improper angle (radians)

Precomputed Values

• two_k: Stores 2*k for efficient derivative computation
• cos_xi0, sin_xi0: Precomputed for angle-difference formula

Implementations

impl<T: Vector> Harm<T>

pub fn new(k: f64, xi0: f64) -> Self

Creates a new harmonic improper potential.

Arguments

• k: Force constant (energy/radian² units)
• xi0: Equilibrium angle (radians)

Example

use potentials::imp::Harm;

// Planar constraint for aromatic ring
let planar = Harm::<f64>::planar(40.0);

// Chiral center constraint
let chiral = Harm::<f64>::tetrahedral(40.0);

pub fn planar(k: f64) -> Self

Creates for planar geometry (xi0 = 0).

pub fn tetrahedral(k: f64) -> Self

Creates for tetrahedral geometry (xi0 = 35.26°).

The tetrahedral angle from the base is arcsin(1/sqrt(3)) ≈ 35.26°

Trait Implementations

impl<T: Clone> Clone for Harm<T>

fn clone(&self) -> Harm<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for Harm<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: PartialEq> PartialEq for Harm<T>

fn eq(&self, other: &Harm<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: Vector> Potential4<T> for Harm<T>

fn energy(&self, cos_xi: T, sin_xi: T) -> T

Computes the potential energy.

V = k * (xi - xi0)^2

fn derivative(&self, cos_xi: T, sin_xi: T) -> T

Computes dV/d(xi).

dV/d(xi) = 2k * (xi - xi0)

fn energy_derivative(&self, cos_xi: T, sin_xi: T) -> (T, T)

Computes energy and derivative together (optimized).

Shares the computation of sin_delta, cos_delta, and delta_xi.

impl<T: Copy> Copy for Harm<T>

impl<T> StructuralPartialEq for Harm<T>