Histogram.rows: def of bend-parallel@0.1.0.0
Import: import bend-parallel@0.1.0.0/histogram.bend as Histogram
Lines 140-156 of bend-parallel@0.1.0.0/histogram.bend: https://jend.leeeet.dev/read.txt?path=bend-parallel@0.1.0.0/histogram.bend&start_line=140&end_line=156

import Base

# Pass 1's forks: d levels down to the blocks under block index i. fk and
# ft are two handles each to the keys and the table. Block i reads only
# its keys and reads and writes only its row (entries i * 2^kb to
# i * 2^kb + K - 1): no two lanes touch one slot.
def rows(+d: Nat, +i: U32, +e: Nat, +kb: Nat, +k: U32, fk: Array<U32> & Array<U32>, ft: Array<U32> & Array<U32>) -> Two:
  match d:
    case 0n:
      (ks, ks2) = fk
      (t, t2) = ft
      two.rejoin(ks2, t2, rows.leaf(i, e, kb, k, ks, t))
    case 1n+p:
      (k0, k1) = fk
      (t0, t1) = ft
      +j = (i * 2 : U32)
      l r = rows(p, j, e, kb, k, Array.fork(U32, k0), Array.fork(U32, t0))
        rows(p, (j + 1 : U32), e, kb, k, Array.fork(U32, k1), Array.fork(U32, t1))
      two.join(l, r)

Uses (12):
  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=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=Base/base.bend&name=U32.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.mul
  https://jend.leeeet.dev/definition.txt?path=bend-parallel@0.1.0.0/histogram.bend&name=Two
  https://jend.leeeet.dev/definition.txt?path=bend-parallel@0.1.0.0/histogram.bend&name=rows.leaf
  https://jend.leeeet.dev/definition.txt?path=bend-parallel@0.1.0.0/histogram.bend&name=two.join
  https://jend.leeeet.dev/definition.txt?path=bend-parallel@0.1.0.0/histogram.bend&name=two.rejoin