1	import Base
2	import ../../shape/core.bend as Shape
3	import ../core.bend as Core
4	import ./fold.bend as Fold
5	
6	# Ordered-fold family, sum instance: fold every word of the input, in index
7	# order, with F32.add.
8	
9	def add(operation: Unit, accumulator: F32, word: F32) -> F32:
10	  F32.add(accumulator, word)
11	
12	def position(plan: Unit, index: Nat) -> Nat:
13	  index
14	
15	def every(plan: Unit, index: Nat) -> Bool:
16	  True{}
17	
18	def sum(input: Core.Dynamic) -> Core.Dynamic & Result<&2, &1, Core.Error, F32>:
19	  Core.Packed{+shape, tensor} = input
20	  Fold.run(~Unit, ~add, ~Unit, ~position, ~every, Unit{}, Unit{}, Shape.elements(shape), Core.Packed{shape, tensor})