#![cfg(test)]
use super::*;
use crate::physics::single_chain::test::Parameters;
mod base
{
use super::*;
use rand::Rng;
#[test]
fn init()
{
let parameters = Parameters::default();
let _ = FJC::init(parameters.number_of_links_minimum, parameters.link_length_reference, parameters.hinge_mass_reference);
}
#[test]
fn number_of_links()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
assert_eq!(number_of_links, FJC::init(number_of_links, parameters.link_length_reference, parameters.hinge_mass_reference).number_of_links);
}
}
#[test]
fn link_length()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
assert_eq!(link_length, FJC::init(parameters.number_of_links_minimum, link_length, parameters.hinge_mass_reference).link_length);
}
}
#[test]
fn hinge_mass()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
assert_eq!(hinge_mass, FJC::init(parameters.number_of_links_minimum, parameters.link_length_reference, hinge_mass).hinge_mass);
}
}
#[test]
fn all_parameters()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
assert_eq!(number_of_links, model.number_of_links);
assert_eq!(link_length, model.link_length);
assert_eq!(hinge_mass, model.hinge_mass);
}
}
}
mod nondimensional
{
use super::*;
use rand::Rng;
#[test]
fn helmholtz_free_energy()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let nondimensional_helmholtz_free_energy = model.nondimensional_helmholtz_free_energy(&nondimensional_force, &temperature);
let force = nondimensional_force*BOLTZMANN_CONSTANT*temperature/link_length;
let helmholtz_free_energy = model.helmholtz_free_energy(&force, &temperature);
let residual_abs = &helmholtz_free_energy/BOLTZMANN_CONSTANT/temperature - &nondimensional_helmholtz_free_energy;
let residual_rel = &residual_abs/&nondimensional_helmholtz_free_energy;
assert!(residual_abs.abs() <= parameters.abs_tol);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
#[test]
fn helmholtz_free_energy_per_link()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let nondimensional_helmholtz_free_energy_per_link = model.nondimensional_helmholtz_free_energy_per_link(&nondimensional_force, &temperature);
let force = nondimensional_force*BOLTZMANN_CONSTANT*temperature/link_length;
let helmholtz_free_energy_per_link = model.helmholtz_free_energy_per_link(&force, &temperature);
let residual_abs = &helmholtz_free_energy_per_link/BOLTZMANN_CONSTANT/temperature - &nondimensional_helmholtz_free_energy_per_link;
let residual_rel = &residual_abs/&nondimensional_helmholtz_free_energy_per_link;
assert!(residual_abs.abs() <= parameters.abs_tol);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
#[test]
fn relative_helmholtz_free_energy()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let nondimensional_relative_helmholtz_free_energy = model.nondimensional_relative_helmholtz_free_energy(&nondimensional_force);
let force = nondimensional_force*BOLTZMANN_CONSTANT*temperature/link_length;
let relative_helmholtz_free_energy = model.relative_helmholtz_free_energy(&force, &temperature);
let residual_abs = &relative_helmholtz_free_energy/BOLTZMANN_CONSTANT/temperature - &nondimensional_relative_helmholtz_free_energy;
let residual_rel = &residual_abs/&nondimensional_relative_helmholtz_free_energy;
assert!(residual_abs.abs() <= parameters.abs_tol);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
#[test]
fn relative_helmholtz_free_energy_per_link()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let nondimensional_relative_helmholtz_free_energy_per_link = model.nondimensional_relative_helmholtz_free_energy_per_link(&nondimensional_force);
let force = nondimensional_force*BOLTZMANN_CONSTANT*temperature/link_length;
let relative_helmholtz_free_energy_per_link = model.relative_helmholtz_free_energy_per_link(&force, &temperature);
let residual_abs = &relative_helmholtz_free_energy_per_link/BOLTZMANN_CONSTANT/temperature - &nondimensional_relative_helmholtz_free_energy_per_link;
let residual_rel = &residual_abs/&nondimensional_relative_helmholtz_free_energy_per_link;
assert!(residual_abs.abs() <= parameters.abs_tol);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
}
mod per_link
{
use super::*;
use rand::Rng;
#[test]
fn helmholtz_free_energy()
{
let parameters = Parameters::default();
let mut rng = rand::thread_rng();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let force = nondimensional_force*BOLTZMANN_CONSTANT*temperature/link_length;
let helmholtz_free_energy = model.helmholtz_free_energy(&force, &temperature);
let helmholtz_free_energy_per_link = model.helmholtz_free_energy_per_link(&force, &temperature);
let residual_abs = &helmholtz_free_energy/(number_of_links as f64) - &helmholtz_free_energy_per_link;
let residual_rel = &residual_abs/&helmholtz_free_energy_per_link;
assert!(residual_abs.abs() <= parameters.abs_tol);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
#[test]
fn relative_helmholtz_free_energy()
{
let parameters = Parameters::default();
let mut rng = rand::thread_rng();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let force = nondimensional_force*BOLTZMANN_CONSTANT*temperature/link_length;
let relative_helmholtz_free_energy = model.relative_helmholtz_free_energy(&force, &temperature);
let relative_helmholtz_free_energy_per_link = model.relative_helmholtz_free_energy_per_link(&force, &temperature);
let residual_abs = &relative_helmholtz_free_energy/(number_of_links as f64) - &relative_helmholtz_free_energy_per_link;
let residual_rel = &residual_abs/&relative_helmholtz_free_energy_per_link;
assert!(residual_abs.abs() <= parameters.abs_tol);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
#[test]
fn nondimensional_helmholtz_free_energy()
{
let parameters = Parameters::default();
let mut rng = rand::thread_rng();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let nondimensional_helmholtz_free_energy = model.nondimensional_helmholtz_free_energy(&nondimensional_force, &temperature);
let nondimensional_helmholtz_free_energy_per_link = model.nondimensional_helmholtz_free_energy_per_link(&nondimensional_force, &temperature);
let residual_abs = &nondimensional_helmholtz_free_energy/(number_of_links as f64) - &nondimensional_helmholtz_free_energy_per_link;
let residual_rel = &residual_abs/&nondimensional_helmholtz_free_energy_per_link;
assert!(residual_abs.abs() <= parameters.abs_tol);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
#[test]
fn nondimensional_relative_helmholtz_free_energy()
{
let parameters = Parameters::default();
let mut rng = rand::thread_rng();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let nondimensional_relative_helmholtz_free_energy = model.nondimensional_relative_helmholtz_free_energy(&nondimensional_force);
let nondimensional_relative_helmholtz_free_energy_per_link = model.nondimensional_relative_helmholtz_free_energy_per_link(&nondimensional_force);
let residual_abs = &nondimensional_relative_helmholtz_free_energy/(number_of_links as f64) - &nondimensional_relative_helmholtz_free_energy_per_link;
let residual_rel = &residual_abs/&nondimensional_relative_helmholtz_free_energy_per_link;
assert!(residual_abs.abs() <= parameters.abs_tol);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
}
mod relative
{
use super::*;
use crate::physics::single_chain::ZERO;
use rand::Rng;
#[test]
fn helmholtz_free_energy()
{
let parameters = Parameters::default();
let mut rng = rand::thread_rng();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let force = nondimensional_force*BOLTZMANN_CONSTANT*temperature/link_length;
let helmholtz_free_energy = model.helmholtz_free_energy(&force, &temperature);
let helmholtz_free_energy_0 = model.helmholtz_free_energy(&(ZERO*BOLTZMANN_CONSTANT*temperature/link_length), &temperature);
let relative_helmholtz_free_energy = model.relative_helmholtz_free_energy(&force, &temperature);
let residual_abs = &helmholtz_free_energy - &helmholtz_free_energy_0 - &relative_helmholtz_free_energy;
let residual_rel = &residual_abs/&helmholtz_free_energy_0;
assert!(residual_abs.abs() <= parameters.abs_tol*BOLTZMANN_CONSTANT*temperature/link_length);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
#[test]
fn helmholtz_free_energy_per_link()
{
let parameters = Parameters::default();
let mut rng = rand::thread_rng();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let force = nondimensional_force*BOLTZMANN_CONSTANT*temperature/link_length;
let helmholtz_free_energy_per_link = model.helmholtz_free_energy_per_link(&force, &temperature);
let helmholtz_free_energy_per_link_0 = model.helmholtz_free_energy_per_link(&(ZERO*BOLTZMANN_CONSTANT*temperature/link_length), &temperature);
let relative_helmholtz_free_energy_per_link = model.relative_helmholtz_free_energy_per_link(&force, &temperature);
let residual_abs = &helmholtz_free_energy_per_link - &helmholtz_free_energy_per_link_0 - &relative_helmholtz_free_energy_per_link;
let residual_rel = &residual_abs/&helmholtz_free_energy_per_link_0;
assert!(residual_abs.abs() <= parameters.abs_tol*BOLTZMANN_CONSTANT*temperature/link_length);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
#[test]
fn nondimensional_helmholtz_free_energy()
{
let parameters = Parameters::default();
let mut rng = rand::thread_rng();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let nondimensional_helmholtz_free_energy = model.nondimensional_helmholtz_free_energy(&nondimensional_force, &temperature);
let nondimensional_helmholtz_free_energy_0 = model.nondimensional_helmholtz_free_energy(&ZERO, &temperature);
let nondimensional_relative_helmholtz_free_energy = model.nondimensional_relative_helmholtz_free_energy(&nondimensional_force);
let residual_abs = &nondimensional_helmholtz_free_energy - &nondimensional_helmholtz_free_energy_0 - &nondimensional_relative_helmholtz_free_energy;
let residual_rel = &residual_abs/&nondimensional_helmholtz_free_energy_0;
assert!(residual_abs.abs() <= parameters.abs_tol);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
#[test]
fn nondimensional_helmholtz_free_energy_per_link()
{
let parameters = Parameters::default();
let mut rng = rand::thread_rng();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_force = parameters.nondimensional_force_reference + parameters.nondimensional_force_scale*(0.5 - rng.gen::<f64>());
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let nondimensional_helmholtz_free_energy_per_link = model.nondimensional_helmholtz_free_energy_per_link(&nondimensional_force, &temperature);
let nondimensional_helmholtz_free_energy_per_link_0 = model.nondimensional_helmholtz_free_energy_per_link(&ZERO, &temperature);
let nondimensional_relative_helmholtz_free_energy_per_link = model.nondimensional_relative_helmholtz_free_energy_per_link(&nondimensional_force);
let residual_abs = &nondimensional_helmholtz_free_energy_per_link - &nondimensional_helmholtz_free_energy_per_link_0 - &nondimensional_relative_helmholtz_free_energy_per_link;
let residual_rel = &residual_abs/&nondimensional_helmholtz_free_energy_per_link_0;
assert!(residual_abs.abs() <= parameters.abs_tol);
assert!(residual_rel.abs() <= parameters.rel_tol);
}
}
}
mod zero
{
use super::*;
use crate::physics::single_chain::ZERO;
use rand::Rng;
#[test]
fn relative_helmholtz_free_energy()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let relative_helmholtz_free_energy_0 = model.relative_helmholtz_free_energy(&(ZERO*BOLTZMANN_CONSTANT*temperature/link_length), &temperature);
assert!(relative_helmholtz_free_energy_0.abs() <= ZERO*BOLTZMANN_CONSTANT*temperature);
}
}
#[test]
fn relative_helmholtz_free_energy_per_link()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let temperature = parameters.temperature_reference + parameters.temperature_scale*(0.5 - rng.gen::<f64>());
let relative_helmholtz_free_energy_per_link_0 = model.relative_helmholtz_free_energy_per_link(&(ZERO*BOLTZMANN_CONSTANT*temperature/link_length), &temperature);
assert!(relative_helmholtz_free_energy_per_link_0.abs() <= ZERO*BOLTZMANN_CONSTANT*temperature);
}
}
#[test]
fn nondimensional_relative_helmholtz_free_energy()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_relative_helmholtz_free_energy_0 = model.nondimensional_relative_helmholtz_free_energy(&ZERO);
assert!(nondimensional_relative_helmholtz_free_energy_0.abs() <= ZERO);
}
}
#[test]
fn nondimensional_relative_helmholtz_free_energy_per_link()
{
let mut rng = rand::thread_rng();
let parameters = Parameters::default();
for _ in 0..parameters.number_of_loops
{
let number_of_links: u8 = rng.gen_range(parameters.number_of_links_minimum..parameters.number_of_links_maximum);
let link_length = parameters.link_length_reference + parameters.link_length_scale*(0.5 - rng.gen::<f64>());
let hinge_mass = parameters.hinge_mass_reference + parameters.hinge_mass_scale*(0.5 - rng.gen::<f64>());
let model = FJC::init(number_of_links, link_length, hinge_mass);
let nondimensional_relative_helmholtz_free_energy_per_link_0 = model.nondimensional_relative_helmholtz_free_energy_per_link(&ZERO);
assert!(nondimensional_relative_helmholtz_free_energy_per_link_0.abs() <= ZERO);
}
}
}