def descend_at

bendtorch-core@0.1.0.0 · src/autograd/sgd.bend:127

import Base
import bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend as Backward

127# Updates entry id of a newest-first list of count entries and keeps every
128# other entry.
129def descend_at(+lr: F32, entries: List<&1, Backward.Entry>, +count: Nat, +id: Nat, same: Bool) -> Walked():
130  match entries count same:
131    case Nil{} count same:
132      (Nil{}, Fail{UnknownNode{}})
133    case Con{entry, rest} 0n same:
134      (entry <> rest, Fail{UnknownNode{}})
135    case Con{entry, rest} 1n+below True{}:
136      placed(rest, descend(lr, entry))
137    case Con{entry, rest} 1n+below False{}:
138      kept(entry, descend_at(lr, rest, below, id, Backward.at_head(below, id)))