Struct Bussi 

pub struct Bussi { /* private fields */ }

Stochastic momentum rescaling.

The time constant $\tau$ sets how long the kinetic energy of the system takes to decay to equilibrium.

When $\tau$ is 0, the rescaling factor $\alpha$ is:

 \alpha = \sqrt{\frac{g kT}{K}}

where $K$ is the instantaneous kinetic energy of the corresponding translational or rotational degrees of freedom, $N$ is the number of degrees of freedom, and $g$ is a random value sampled from the gamma distribution $\Gamma(N, 1)$ with the probability density function:

   f_N(g) = \frac{1}{\Gamma{(N)}} g^{N-1} e^{-g}

When $\tau$ is non-zero, $\alpha$ is given by:

\alpha = \sqrt{e^{-\delta t / \tau}
     + (1 - e^{-\delta t / \tau}) \frac{(2 g + n^2) kT}{2 K}
     + 2 n \sqrt{e^{-\delta t / \tau} (1-e^{-\delta t / \tau})
        \frac{kT}{2 K}}}

where $\delta t$ is the integration time step size and $n$ is a random value sampled from the standard normal distribution $\mathcal{N}(0, 1)$.

Reference

• Bussi et al. 2007

Example

use hoomd_md::thermostat::Bussi;

let bussi = Bussi::new(0.5);

Implementations

impl Bussi

pub fn new(tau: f64) -> Self

Construct a new Bussi thermostat with the given time constant.

Example

use hoomd_md::thermostat::Bussi;

let bussi = Bussi::new(0.5);

pub fn energy(&self) -> f64

The total energy of the thermostat.

Example

use hoomd_md::thermostat::Bussi;

let bussi = Bussi::new(0.1);
let energy = bussi.energy();

Trait Implementations

impl Clone for Bussi

fn clone(&self) -> Bussi

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Bussi

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

Formats the value using the given formatter.

impl Default for Bussi

fn default() -> Bussi

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Bussi

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Bussi

fn eq(&self, other: &Bussi) -> 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 Serialize for Bussi

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<M> Thermostat<M> for Bussi

where M: Temperature,

fn integrate_half_step_one<R: Rng + ?Sized>( &mut self, rng: &mut R, macrostate: &M, delta_t: f64, kinetic_energy: f64, degrees_of_freedom: usize, ) -> f64

Integrate the thermostat one half step forward in time.

fn integrate_half_step_two<R: Rng + ?Sized>( &mut self, _rng: &mut R, _macrostate: &M, _delta_t: f64, _kinetic_energy: f64, _degrees_of_freedom: usize, ) -> f64

Integrate the thermostat one half step forward in time.

impl StructuralPartialEq for Bussi