band

Julia

struct Band
Band(rows::Vector{Tuple{Int64, Int64}}, ridx::Vector{Union{Int64, String}}, cidx::Vector{EarthSciAST.ASTExpr}, coef::EarthSciAST.ASTExpr, contracted::Vector{Tuple{String, Int64, Int64}}, guard::Union{Nothing, EarthSciAST.ASTExpr})
Band(rows, ridx, cidx, coef, contracted, guard)
Band(rows, ridx, cidx, coef)
Band(rows, ridx, cidx, coef, contracted)

Band

One structured block of ∂(rhs of the equation for u)/∂v:

• rows::Vector{Tuple{Int,Int}} — a rectangular region of u’s index space, per-dimension inclusive (lo, hi). Empty for a scalar u.
• ridx::Vector{Union{String,Int}} — per-dimension row index: a free index NAME ranging over rows[k], or a constant Int for a singleton dimension.
• cidx::Vector{ASTExpr} — v’s column index expressions, one per dimension of v, in terms of the row index names. Empty for scalar v.
• coef::ASTExpr — scalar ESM coefficient expression in terms of the row index names (plus parameters and other states).
• contracted::Vector{Tuple{String,Int,Int}} — free CONTRACTED column dimensions (name, lo, hi): when non-empty the band denotes, for every row cell AND every value of the contracted names over their inclusive ranges, an entry J[row, cidx(row, contracted…)] += coef(row, contracted…) — entries meeting at one column ACCUMULATE (this is how a reduce: "+" faq node’s sum over a gathered column materializes). Empty for ordinary bands.
• guard::Union{Nothing,ASTExpr} — an exact point predicate (the block’s where field) over the row and contracted index names, literals and const gathers: a point contributes iff it holds. What a filtered faq node’s non-rectangular window (gk < gke) leaves after its box is split at affine breakpoints; nothing for every rectangular band.

The band is the symbolic, portable analogue of the tree-walk’s _AccDesc state-read descriptors: cidx of the form row ± const is an affine stencil offset, cidx == ridx is a diagonal (per-cell) coupling, and a cidx referencing a contracted name is an indirect/contracted gather (source–receptor matrices, regrid joins, conn[]-table stencils).

Source

Python

class Band
Band(rows: list[tuple[int, int]], ridx: list, cidx: list, coef: Expr, contracted: list[tuple[str, int, int]] = list(), guard: Expr | None = None)

One structured block of ∂(rhs of the equation for u)/∂v — see the Julia reference docstring and esm-jacobian-spec.md §4. contracted holds free contracted column dimensions (name, lo, hi); guard is an exact point predicate (the entry’s where field) over the row and contracted index names — what a filtered faq node’s non-rectangular window leaves after its box is split at affine breakpoints — or None for every rectangular band. Rebuild with dataclasses.replace so the guard travels.

Source

Rust

pub struct Band {
    pub rows: Vec<(i64, i64)>,
    pub ridx: Vec<RIdx>,
    pub cidx: Vec<Expr>,
    pub coef: Expr,
    pub contracted: Vec<(String, i64, i64)>,
    pub guard: Option<Expr>,
}

One rectangular region of a Jacobian block: the rows it covers (rows, 1-based inclusive ranges, named by ridx), the column-index expressions (cidx) and the coefficient expression (coef). contracted lists extra column dimensions that accumulate (summed) at assembly. guard is an exact point predicate (the entry’s where field) over the row and contracted index names, literals and const gathers: a point contributes iff it holds. What a filtered faq node’s non-rectangular window (gk < gke) leaves after its box is split at affine breakpoints; None for every rectangular band.

Source · Rust docs