Struct Tensor4 

pub struct Tensor4 {
    pub data: [[[[f64; 3]; 3]; 3]; 3],
}

Fourth-order tensor with 81 components stored as [i][j][k][l].

Fields

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

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

Implementations

impl Tensor4

pub fn zero() -> Self

Zero fourth-order tensor.

pub fn identity_sym() -> Self

Symmetric fourth-order identity: I_sym_ijkl = 0.5 * (δ_ik δ_jl + δ_il δ_jk).

pub fn isotropic(lambda: f64, mu: f64) -> Self

Isotropic linear elasticity tensor: C_ijkl = λ δ_ij δ_kl + μ (δ_ik δ_jl + δ_il δ_jk).

pub fn double_contract_2(&self, t: &Tensor2) -> Tensor2

Double contraction with a second-order tensor: result_ij = Σ_kl C_ijkl A_kl.

impl Tensor4

pub fn deviatoric_projector() -> Self

Deviatoric projector: P_dev_ijkl = I_sym_ijkl - (1/3) delta_ij delta_kl.

pub fn to_voigt_matrix(&self) -> [[f64; 6]; 6]

Convert isotropic elasticity tensor to Voigt matrix (6x6).

Returns [6][6] matrix.

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

Scale all components by a scalar.

pub fn add(&self, other: &Tensor4) -> Self

Add two fourth-order tensors.

impl Tensor4

pub fn double_contract_4(&self, other: &Tensor4) -> Tensor4

Double contraction of two fourth-order tensors: (C::D)_ijmn = Σ_kl C_ijkl D_klmn.

pub fn single_contract_right(&self, a: &Tensor2) -> Tensor4

Single contraction of C with a second-order tensor on the last two indices: (C · A)_ijkl = Σ_m C_ijkm A_ml.

Result is a fourth-order tensor.

pub fn has_minor_symmetry(&self, tol: f64) -> bool

Check minor symmetry: C_ijkl = C_jikl = C_ijlk.

Returns true if both left-minor and right-minor symmetries hold within tol.

pub fn has_major_symmetry(&self, tol: f64) -> bool

Check major symmetry: C_ijkl = C_klij.

Returns true if major symmetry holds within tol.

pub fn symmetrize_minor(&self) -> Tensor4

Enforce minor symmetry by symmetrizing: C_sym_ijkl = 0.25 * (C_ijkl + C_jikl + C_ijlk + C_jilk).

pub fn symmetrize_major(&self) -> Tensor4

Enforce major symmetry by averaging: C_sym_ijkl = 0.5*(C_ijkl + C_klij).

pub fn rotate(&self, r: &Tensor2) -> Tensor4

Rotate a fourth-order tensor: C’_ijkl = R_ia R_jb R_kc R_ld C_abcd.

pub fn volumetric_projector() -> Self

Build the isotropic volumetric projector: P_vol_ijkl = (1/3) * delta_ij * delta_kl.

pub fn identity() -> Self

The fourth-order identity: I_ijkl = delta_ik * delta_jl.

pub fn sub(&self, other: &Tensor4) -> Self

Subtract two fourth-order tensors.

pub fn norm(&self) -> f64

Frobenius norm of the fourth-order tensor: sqrt(Σ C_ijkl^2).