#[cfg(test)]
mod test;
use crate::{
fem::block::element::{
ElementNodalEitherCoordinates, FiniteElement, ParametricCoordinate, ParametricCoordinates,
ParametricReference, ShapeFunctions, ShapeFunctionsGradients,
linear::{LinearElement, LinearFiniteElement, M},
},
math::{ScalarList, Tensor},
};
use std::f64::consts::SQRT_2;
const G: usize = 1;
const N: usize = 4;
const P: usize = N;
const EDGES: usize = 6;
pub type Tetrahedron = LinearElement<G, N>;
impl FiniteElement<G, M, N, P> for Tetrahedron {
fn integration_points() -> ParametricCoordinates<G, M> {
[[0.25; M]].into()
}
fn integration_weights(&self) -> &ScalarList<G> {
&self.integration_weights
}
fn parametric_reference() -> ParametricReference<M, N> {
[
[0.0, 0.0, 0.0],
[1.0, 0.0, 0.0],
[0.0, 1.0, 0.0],
[0.0, 0.0, 1.0],
]
.into()
}
fn parametric_weights() -> ScalarList<G> {
[1.0 / 6.0; G].into()
}
fn scaled_jacobians<const I: usize>(
nodal_coordinates: ElementNodalEitherCoordinates<I, N>,
) -> ScalarList<P> {
let numerator = ((&nodal_coordinates[1] - &nodal_coordinates[0])
.cross(&(&nodal_coordinates[2] - &nodal_coordinates[0]))
* (&nodal_coordinates[3] - &nodal_coordinates[0]))
* SQRT_2;
let lengths = lengths(nodal_coordinates);
[
numerator / (lengths[0] * lengths[2] * lengths[3]),
numerator / (lengths[0] * lengths[1] * lengths[4]),
numerator / (lengths[1] * lengths[2] * lengths[5]),
numerator / (lengths[3] * lengths[4] * lengths[5]),
]
.into()
}
fn shape_functions(parametric_coordinate: ParametricCoordinate<M>) -> ShapeFunctions<N> {
let [xi_1, xi_2, xi_3] = parametric_coordinate.into();
[1.0 - xi_1 - xi_2 - xi_3, xi_1, xi_2, xi_3].into()
}
fn shape_functions_gradients(
_parametric_coordinate: ParametricCoordinate<M>,
) -> ShapeFunctionsGradients<M, N> {
[
[-1.0, -1.0, -1.0],
[1.0, 0.0, 0.0],
[0.0, 1.0, 0.0],
[0.0, 0.0, 1.0],
]
.into()
}
}
impl LinearFiniteElement<G, N> for Tetrahedron {}
fn edges<const I: usize>(
nodal_coordinates: ElementNodalEitherCoordinates<I, N>,
) -> ElementNodalEitherCoordinates<I, 6> {
[
&nodal_coordinates[1] - &nodal_coordinates[0],
&nodal_coordinates[2] - &nodal_coordinates[1],
&nodal_coordinates[0] - &nodal_coordinates[2],
&nodal_coordinates[3] - &nodal_coordinates[0],
&nodal_coordinates[3] - &nodal_coordinates[1],
&nodal_coordinates[3] - &nodal_coordinates[2],
]
.into()
}
fn lengths<const I: usize>(
nodal_coordinates: ElementNodalEitherCoordinates<I, N>,
) -> ScalarList<EDGES> {
edges(nodal_coordinates)
.into_iter()
.map(|edge| edge.norm())
.collect()
}