Struct Quart 

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

Quartic bond potential.

Parameters

• k2: Quadratic force constant (energy/length^2 units)
• k3: Cubic correction (energy/length^3 units)
• k4: Quartic correction (energy/length^4 units)
• r0: Equilibrium distance (length units)

Implementations

impl<T: Vector> Quart<T>

pub fn new(k2: f64, k3: f64, k4: f64, r0: f64) -> Self

Creates a new quartic bond potential.

Arguments

• k2: Quadratic force constant
• k3: Cubic correction
• k4: Quartic correction
• r0: Equilibrium bond length

Example

use potentials::bond::Quart;

// Class II force field parameters
let bond = Quart::<f64>::new(300.0, -50.0, 10.0, 1.54);

pub fn symmetric(k2: f64, k4: f64, r0: f64) -> Self

Creates a quartic potential with only quadratic and quartic terms.

This is symmetric about the equilibrium.

pub fn k2(&self) -> T

Returns the quadratic coefficient.

pub fn k3(&self) -> T

Returns the cubic coefficient.

pub fn k4(&self) -> T

Returns the quartic coefficient.

pub fn r0(&self) -> T

Returns the equilibrium distance.

Trait Implementations

impl<T: Clone> Clone for Quart<T>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for Quart<T>

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

Formats the value using the given formatter.

impl<T: PartialEq> PartialEq for Quart<T>

fn eq(&self, other: &Quart<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> Potential2<T> for Quart<T>

fn energy(&self, r_sq: T) -> T

Computes the potential energy.

V(r) = k2*(r-r0)^2 + k3*(r-r0)^3 + k4*(r-r0)^4

fn force_factor(&self, r_sq: T) -> T

Computes the force factor.

dV/dr = 2*k2*(r-r0) + 3*k3*(r-r0)^2 + 4*k4*(r-r0)^3
S = -(dV/dr)/r

fn energy_force(&self, r_sq: T) -> (T, T)

Computes energy and force factor together (optimized).

Shares the computation of r, r_inv, dr, and dr_sq.

impl<T: Copy> Copy for Quart<T>

impl<T> StructuralPartialEq for Quart<T>