Struct Cos 

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

Harmonic cosine angle potential.

Parameters

• k: Force constant (energy units)
• cos0: Equilibrium angle cosine

Implementations

impl<T: Vector> Cos<T>

pub fn new(k: f64, cos0: f64) -> Self

Creates a new cosine angle potential.

Arguments

• k: Force constant (energy units)
• cos0: Cosine of equilibrium angle

Example

use potentials::angle::Cos;

// Tetrahedral angle: 109.5 degrees
let cos0 = (109.5_f64 * std::f64::consts::PI / 180.0).cos();
let angle = Cos::<f64>::new(100.0, cos0);

pub fn from_theta(k: f64, theta0: f64) -> Self

Creates from equilibrium angle in radians.

pub fn from_degrees(k: f64, theta0_deg: f64) -> Self

Creates from equilibrium angle in degrees.

pub fn k(&self) -> T

Returns the force constant.

pub fn cos0(&self) -> T

Returns the equilibrium cosine.

Trait Implementations

impl<T: Clone> Clone for Cos<T>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Copy> Copy for Cos<T>

impl<T: Debug> Debug for Cos<T>

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

Formats the value using the given formatter.

impl<T: PartialEq> PartialEq for Cos<T>

fn eq(&self, other: &Cos<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> Potential3<T> for Cos<T>

fn energy(&self, _r_ij_sq: T, _r_jk_sq: T, cos_theta: T) -> T

Computes the potential energy.

V = k * (cos(theta) - cos0)^2

No acos required!

fn derivative(&self, _r_ij_sq: T, _r_jk_sq: T, cos_theta: T) -> T

Computes dV/d(cos_theta).

dV/d(cos_theta) = 2 * k * (cos_theta - cos0)

fn energy_derivative(&self, _r_ij_sq: T, _r_jk_sq: T, cos_theta: T) -> (T, T)

Computes energy and derivative together (optimized).

Shares the computation of delta.

impl<T: PartialEq> StructuralPartialEq for Cos<T>