Parallel.degrees_tree: def of bend-visgraph@2.0.0.0
Import: import bend-visgraph@2.0.0.0/parallel.bend as Parallel
Lines 180-194 of bend-visgraph@2.0.0.0/parallel.bend: https://jend.leeeet.dev/read.txt?path=bend-visgraph@2.0.0.0/parallel.bend&start_line=180&end_line=194

import Base
import bend-visgraph@2.0.0.0/visgraph.bend as VG

# Forks down the build's tree of EJoin into VG.degrees.into, which
# forks nothing, so the runtime spreads the tallies over every thread.
def degrees_tree(depth: Nat, es: VG.Edges, dd: Array<U32> & Array<U32>) -> Array<U32>:
  match depth es:
    case 1n++p VG.EJoin{a, b}:
      (d1, d2) = dd
      x y = degrees_tree(p, a, Array.fork(U32, d1)) degrees_tree(p, b, Array.fork(U32, d2))
      Array.join(U32, x, y)
    case 0n VG.EJoin{a, b}:
      (d1, d2) = dd
      x y = VG.degrees.into(a, d1) VG.degrees.into(b, d2)
      Array.join(U32, x, y)
    case _ _:
      (d1, d2) = dd
      VG.degrees.into(es, Array.join(U32, d1, d2))

Uses (9):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Array
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Array.fork
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Array.join
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Pair
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Sigma
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=bend-visgraph@2.0.0.0/visgraph.bend&name=Edges
  https://jend.leeeet.dev/definition.txt?path=bend-visgraph@2.0.0.0/visgraph.bend&name=degrees.into