BendMlLlama.tree_sum: def of bend-ml-llama@0.2.1.0
Import: import bend-ml-llama@0.2.1.0/main.bend as BendMlLlama
Lines 373-384 of bend-ml-llama@0.2.1.0/main.bend: https://jend.leeeet.dev/read.txt?path=bend-ml-llama@0.2.1.0/main.bend&start_line=373&end_line=384

import Base

# the sum as a balanced tree of additions (pairwise summation): its rounding error grows with log2(n), not n, as
# in PyTorch's cascade sum. A running sum loses the small squares next to a large one (NOTES, 2026-10-10).
def tree_sum(fuel: Nat, xs: List<&2, F32>) -> F32:
  match fuel xs:
    case _ Nil{}:
      0.0
    case _ Con{+a, Nil{}}:
      a
    case 0n Con{+a, t}:
      list.sum.go(t, a)
    case 1n+p Con{+a, t}:
      tree_sum(p, pair_sums(Con{a, t}))

Uses (5):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=bend-ml-llama@0.2.1.0/main.bend&name=list.sum.go
  https://jend.leeeet.dev/definition.txt?path=bend-ml-llama@0.2.1.0/main.bend&name=pair_sums