Struct AddResidual 

pub struct AddResidual {
    lower: [DMatrix<Complex>; 2],
    upper: [DMatrix<Complex>; 2],
    solve: InternalSolve,
    down: DMatrix<Complex>,
}

What add saves for its pullback: four of the eight input blocks, the internal fields and their factorization.

The pullback reads only blocks 1 and 3 of the lower S-matrix and blocks 0 and 2 of the upper one; the other four input blocks are released after the forward pass.

Fields

lower: [DMatrix<Complex>; 2]

Lower blocks 1 and 3: reflection of waves incident from the positive side (above) and downward transmission.

upper: [DMatrix<Complex>; 2]

Upper blocks 0 and 2: upward transmission and reflection of waves incident from the negative side (below).

solve: InternalSolve

Upgoing internal fields (I - L1 U2)^-1 [L0, L1 U3] and their factorization.

down: DMatrix<Complex>

Downgoing internal fields U2 up + [0, U3].

Implementations

impl AddResidual

pub fn state_size(n: usize) -> Result<usize>

Byte count for saved composition state with n modes per direction.

impl AddResidual

pub fn shape(&self) -> (usize, usize)

The shape (n, n) of each scattering block, with n modes in each direction.

pub fn pushforward(&self, lower: &Blocks, upper: &Blocks) -> Result<Blocks>

Propagate all eight block tangents through the recorded internal-field solve. The forward factorization is reused; no dense Jacobian is formed.

pub fn pullback(&self, cotangent: &Blocks) -> Result<AddGradient>

Input cotangents under dL = Re(sum(conj(g) * dx)).

Trait Implementations

impl Debug for AddResidual

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl SavedState for AddResidual

fn save_state(&self) -> Result<Vec<u8>>

Copy the saved numerical state into its fixed byte layout.

fn from_state(bytes: &[u8]) -> Result<Self>

Restore numerical state from bytes produced by this extension.