Sbx.loop.go: def of unified-nsga-iii@0.2.2.0
Import: import unified-nsga-iii@0.2.2.0/sbx.bend as Sbx
Lines 92-145 of unified-nsga-iii@0.2.2.0/sbx.bend: https://jend.leeeet.dev/read.txt?path=unified-nsga-iii@0.2.2.0/sbx.bend&start_line=92&end_line=145

import Base
import unified-nsga-iii@0.2.2.0/bounds.bend as Bounds
import unified-nsga-iii@0.2.2.0/rng.bend as Rng

# Kind: 0n = copy heads (skip or close), 1n = SBX the heads.
# One def so skip/cross are not mutually recursive with `loop`.
def loop.go(
  fuel: Nat,
  kind: Nat,
  xs1: List<&2, F32>,
  xs2: List<&2, F32>,
  ivs: List<&2, Bounds.Interval>,
  +eta: F32,
  rng: Rng.State,
  acc1: List<&2, F32>,
  acc2: List<&2, F32>
) -> Rng.State & List<&2, F32> & List<&2, F32>:
  match fuel kind xs1 xs2 ivs:
    case 0n k a b c:
      done(rng, acc1, acc2)
    case 1n++f 0n +x1 <> +rest1 +x2 <> +rest2 +iv <> ivrest:
      +rng2 = advance(rng, f)
      loop.go(
        f,
        skip_kind(F32.is_gt(Rng.last_double(rng2), 0.5), close_heads(rest1, rest2)),
        rest1, rest2, ivrest, eta, rng2, x1 <> acc1, x2 <> acc2
      )
    case 1n++f 1n+p +x1 <> +rest1 +x2 <> +rest2 +iv <> ivrest:
      +lo = Bounds.lo(iv)
      +hi = Bounds.hi(iv)
      +gt = F32.is_gt(x1, x2)
      +a = Bool.pick(F32, gt, x2, x1)
      +b = Bool.pick(F32, gt, x1, x2)
      +delta = F32.sub(b, a)
      +rng_a = Rng.next_double(rng)
      +rand = Rng.last_double(rng_a)
      +inv = F32.div(1.0, F32.add(eta, 1.0))
      +neg = F32.neg(F32.add(eta, 1.0))
      +alpha1 = F32.sub(2.0, F32.pow(F32.add(1.0, F32.div(F32.mul(2.0, F32.sub(a, lo)), delta)), neg))
      +alpha2 = F32.sub(2.0, F32.pow(F32.add(1.0, F32.div(F32.mul(2.0, F32.sub(hi, b)), delta)), neg))
      +c1v = F32.clamp(F32.mul(0.5, F32.sub(F32.add(a, b), F32.mul(beta(rand, alpha1, inv), delta))), lo, hi)
      +c2v = F32.clamp(F32.mul(0.5, F32.add(F32.add(a, b), F32.mul(beta(rand, alpha2, inv), delta))), lo, hi)
      +rng_b = Rng.next_double(rng_a)
      +sw = F32.is_gt(Rng.last_double(rng_b), 0.5)
      +n1 = Bool.pick(F32, sw, c2v, c1v)
      +n2 = Bool.pick(F32, sw, c1v, c2v)
      +rng_c = advance(rng_b, f)
      loop.go(
        f,
        skip_kind(F32.is_gt(Rng.last_double(rng_c), 0.5), close_heads(rest1, rest2)),
        rest1, rest2, ivrest, eta, rng_c, n1 <> acc1, n2 <> acc2
      )
    case 1n++f k Nil{} b c:
      done(rng, acc1, acc2)
    case 1n++f k a <> as Nil{} c:
      done(rng, acc1, acc2)
    case 1n++f k a <> as b <> bs Nil{}:
      done(rng, acc1, acc2)

Uses (24):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.pick
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32.clamp
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32.div
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32.is_gt
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32.mul
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32.neg
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32.pow
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32.sub
  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=Base/base.bend&name=Pair
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/bounds.bend&name=Interval
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/bounds.bend&name=hi
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/bounds.bend&name=lo
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/rng.bend&name=State
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/rng.bend&name=last_double
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/rng.bend&name=next_double
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/sbx.bend&name=advance
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/sbx.bend&name=beta
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/sbx.bend&name=close_heads
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/sbx.bend&name=done
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/sbx.bend&name=skip_kind