def pack_unpack

bendtorch-core@0.1.0.0 · src/shape/index_proofs.bend:110

import Base
import bendtorch-core@0.1.0.0/src/shape/core.bend as Shape

110def pack_unpack(+a: Nat, +b: Nat, +index: Shape.Fin(Nat.mul(a, b))) -> {Shape.Fin.pack(a, b, Shape.Fin.unpack(a, b, index)) == index : Shape.Fin(Nat.mul(a, b))}:
111  match a:
112    case 0n:
113      match index:
114    case 1n+p:
115      %merge_split(b, Nat.mul(p, b), index) : {Shape.Fin.pack(1n+p, b, Shape.Fin.unpack(1n+p, b, index)) == _ : Shape.Fin(Nat.add(b, Nat.mul(p, b)))}
116      pack_unpack_step(p, b, +index => pack_unpack(p, b, index), Shape.Fin.split(b, Nat.mul(p, b), index))