Struct Tensor3 

pub struct Tensor3 {
    pub data: [[[f64; 3]; 3]; 3],
}

Rank-3 tensor with 27 components stored as data[i][j][k].

Used in continuum mechanics for third-order coupling tensors and the Levi-Civita permutation symbol.

Fields

data: [[[f64; 3]; 3]; 3]

Component array indexed as data[i][j][k].

Implementations

impl Tensor3

pub fn zero() -> Self

Zero tensor.

pub fn levi_civita() -> Self

Levi-Civita (alternating) tensor ε_ijk.

ε_ijk = +1 for even permutations of (0,1,2), -1 for odd permutations, 0 if any index is repeated.

pub fn scale(&self, s: f64) -> Self

Scalar multiplication.

pub fn add(&self, other: &Tensor3) -> Tensor3

Component-wise addition.

pub fn contract_last(&self, v: &[f64; 3]) -> Tensor2

Contract the last index with a vector: result[i][j] = T_ijk * v_k.

pub fn contract_first(&self, v: &[f64; 3]) -> Tensor2

Contract the first index with a vector: result[j][k] = v_i * T_ijk.

pub fn contract_two(&self, a: &[f64; 3], b: &[f64; 3]) -> [f64; 3]

Full contraction with two vectors: result_i = T_ijk * a_j * b_k.

pub fn cross_product(a: &[f64; 3], b: &[f64; 3]) -> [f64; 3]

Cross product of vectors a and b using the Levi-Civita tensor.

(a × b)_i = ε_ijk * a_j * b_k

pub fn norm(&self) -> f64

Frobenius norm: sqrt(sum T_ijk^2).