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Mojo function

reduce

def reduce[params: ContextParams, //, TileFn: def[ws: Int, _r: Int](IndexList[_r]) -> None & ImplicitlyCopyable](row_coords: Coord, axis_size: Int, mut ctx: Context[params], tile_fn: TileFn)

Drives tile_fn over the reduce axis on the target backend, with no monoid state — pure per-tile iteration. See the state-carrying overload below for reduce phases.

Parameters:

• ​params (ContextParams): Comptime dispatch parameters (target + tier).
• ​TileFn (def[ws: Int, _r: Int](IndexList[_r]) -> None & ImplicitlyCopyable): The value-closure type of tile_fn.

Args:

• ​row_coords (Coord): The current row's coords.
• ​axis_size (Int): Length of the reduce axis.
• ​ctx (Context[params]): The dispatch bundle.
• ​tile_fn (TileFn): Per-tile callback; closes over input/output closures.

def reduce[State: ReduceOp, params: ContextParams, //, TileFn: def[ws: Int, _r: Int](mut State, IndexList[_r]) -> None & ImplicitlyCopyable](row_coords: Coord, axis_size: Int, mut ctx: Context[params], mut state: State, tile_fn: TileFn) where (eq TileFn.State, State)

Drives tile_fn over the reduce axis on the target backend.

See the CPU and GPU reduce impls for per-target tier semantics; both call tile_fn[ws, _r] per axis tile, folding into state. tile_fn is a value closure taking state as a mut argument (not a capture — a captured accumulator can't be mutated through a value closure).

Parameters:

• ​State (ReduceOp): The monoid type being accumulated.
• ​params (ContextParams): Comptime dispatch parameters (target + tier).
• ​TileFn (def[ws: Int, _r: Int](mut State, IndexList[_r]) -> None & ImplicitlyCopyable): The value-closure type of tile_fn.

Args:

• ​row_coords (Coord): The current row's coords.
• ​axis_size (Int): Length of the reduce axis.
• ​ctx (Context[params]): The dispatch bundle.
• ​state (State): The caller's monoid accumulator, threaded through by mut reference and mutated in place by tile_fn.
• ​tile_fn (TileFn): Per-tile callback; closes over input closures and folds each tile into state.