Bendtorch.rope_p3: def of bendtorch@1.3.0.0
Import: import bendtorch@1.3.0.0/main.bend as Bendtorch
Lines 2288-2295 of bendtorch@1.3.0.0/main.bend: https://jend.leeeet.dev/read.txt?path=bendtorch@1.3.0.0/main.bend&start_line=2288&end_line=2295

import Base

# one pair (a = x[i1], b = x[i2]) rotated in place; fwd picks the direction: (a cos - b sin, b cos + a sin) forward,
# (a cos + b sin, b cos - a sin) backward, in PyTorch's order of operations for each
def rope_p3(fwd: Bool, +i1: U32, +i2: U32, +a: F32, r2: Array<F32> & F32, rc: Array<F32> & F32, rs: Array<F32> & F32) -> RS3:
  match fwd r2 rc rs:
    case True{} Tuple{x, +b} Tuple{cs, +c} Tuple{sn, +z}:
      RS3{Array.set(F32, Array.set(F32, x, i1, ((a * c : F32) + (F32.neg(b) * z : F32) : F32)), i2, ((b * c : F32) + (a * z : F32) : F32)), cs, sn}
    case False{} Tuple{x, +b} Tuple{cs, +c} Tuple{sn, +z}:
      RS3{Array.set(F32, Array.set(F32, x, i1, ((a * c : F32) + (b * z : F32) : F32)), i2, ((b * c : F32) + F32.neg((a * z : F32)) : F32)), cs, sn}

Uses (11):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Array
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Array.set
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  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.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=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=bendtorch@1.3.0.0/main.bend&name=RS3