Struct ExpansionResidual 

pub struct ExpansionResidual {
    pub(super) basis: MultipoleBasis,
    pub(super) vectors: Vec<[Complex; 3]>,
    pub(super) polarizations: Vec<u8>,
    pub(super) helicity: bool,
    pub(super) fixed_vectors: bool,
}

What expansion saves for its pullback: its inputs. The pullback recomputes the coefficients instead of keeping a Jacobian.

The pullback adds the per-mode position gradients in chunks of consecutive plane modes fixed by the mode count, and the chunk sums in chunk order (numerics::parallel::try_fold_ordered), so the thread count does not change them. Each wavevector gradient belongs to one plane mode, which writes it in place.

Fields

basis: MultipoleBasis

vectors: Vec<[Complex; 3]>

polarizations: Vec<u8>

helicity: bool

fixed_vectors: bool

Implementations

impl ExpansionResidual

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

Multipole output and plane input mode counts.

pub fn validate_tangents( &self, positions: &[[f64; 3]], vectors: &[[Complex; 3]], ) -> Result<()>

Validate position and wavevector tangents for the recorded operation.

pub fn pushforward( &self, positions: &[[f64; 3]], vectors: &[[Complex; 3]], ) -> Result<DMatrix<Complex>>

Push a direction through the position phases and angular coefficients. Cylindrical axial components remain fixed mode labels, as in the pullback.

fn push_column<const N: usize>( &self, labels: &AngularLabels, j: usize, direction: &Direction<N>, positions: &[[f64; 3]], vectors: &[[Complex; 3]], column: &mut [Complex], )

Evaluate and contract the same angular jets used by the reverse contraction.

pub fn pullback( &self, cotangent: &DMatrix<Complex>, ) -> Result<ExpansionGradient>

Differentiate position phases and the full direction-dependent angular coefficient.

fn contract<const N: usize>( &self, labels: &AngularLabels, j: usize, direction: &Direction<N>, cotangent: &DMatrix<Complex>, positions: &mut [[f64; 3]], vector_gradient: &mut [Complex; 3], )

Add the gradients of column j to the position gradients positions and, with direction derivatives (N > 0), to its wavevector gradient vector_gradient.

impl ExpansionResidual

pub fn state_size( multipoles: usize, positions: usize, modes: usize, cylindrical: bool, ) -> Result<usize>

Byte count for expansion into a spherical or cylindrical multipole basis.

Trait Implementations

impl Debug for ExpansionResidual

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

Formats the value using the given formatter.

impl SavedState for ExpansionResidual

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.