use crate::{
EPSILON,
math::{
Scalar,
test::{TestError, assert_eq_from_fd},
},
physics::{
ROOM_TEMPERATURE,
molecular::single_chain::{Ensemble, SquareWellFreelyJointedChain, Thermodynamics},
},
};
const NUM: usize = 333;
#[test]
fn monte_carlo() {
use crate::physics::molecular::single_chain::MonteCarloInextensible;
const N: usize = 5;
let model = SquareWellFreelyJointedChain {
link_length: 1.0,
number_of_links: N as u8,
well_width: 0.3,
ensemble: Ensemble::Isometric(ROOM_TEMPERATURE),
};
let (gamma, g) =
MonteCarloInextensible::nondimensional_radial_distribution(&model, 0.0, 333, 10_000, 1);
gamma
.into_iter()
.zip(g)
.for_each(|(gamma_i, g_i)| println!("[{gamma_i}, {g_i}],"))
}
#[test]
fn finite_difference() -> Result<(), TestError> {
[Ensemble::Isotensional(ROOM_TEMPERATURE)]
.into_iter()
.try_for_each(|ensemble| {
(3..16).into_iter().try_for_each(|number_of_links| {
let model = SquareWellFreelyJointedChain {
link_length: 1.0,
number_of_links,
well_width: 0.3,
ensemble,
};
(30..NUM)
.map(|k| k as Scalar / NUM as Scalar * 10.0)
.into_iter()
.try_for_each(|mut nondimensional_force| {
nondimensional_force += 0.5 * EPSILON;
let mut finite_difference_3 = -model
.nondimensional_gibbs_free_energy_per_link(nondimensional_force)?;
let mut finite_difference_4 =
model.nondimensional_extension(nondimensional_force)?;
nondimensional_force -= EPSILON;
finite_difference_3 -= -model
.nondimensional_gibbs_free_energy_per_link(nondimensional_force)?;
finite_difference_4 -=
model.nondimensional_extension(nondimensional_force)?;
nondimensional_force += 0.5 * EPSILON;
let nondimensional_extension =
model.nondimensional_extension(nondimensional_force)?;
let nondimensional_compliance =
model.nondimensional_compliance(nondimensional_force)?;
assert_eq_from_fd(
&nondimensional_extension,
&(finite_difference_3 / EPSILON),
)?;
assert_eq_from_fd(
&nondimensional_compliance,
&(finite_difference_4 / EPSILON),
)
})
})
})
}