def grad_at

bendtorch-core@0.1.0.0 · src/autograd/tensor_backward.bend:1018

import Base

1018def grad_at(entries: List<&1, Entry>, +count: Nat, +id: Nat, same: Bool) -> Graded():
1019  match entries count same:
1020    case Nil{} count same:
1021      (Nil{}, Fail{UnknownNode{}})
1022    case Con{entry, rest} 0n same:
1023      (entry <> rest, Fail{UnknownNode{}})
1024    case Con{entry, rest} 1n+below True{}:
1025      found_grad(entry, rest)
1026    case Con{entry, rest} 1n+below False{}:
1027      prepend_graded(entry, grad_at(rest, below, id, at_head(below, id)))