TensorBackward.cross_entropy: def of bendtorch-core@0.1.0.0
Import: import bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend as TensorBackward
Lines 1658-1667 of bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend: https://jend.leeeet.dev/read.txt?path=bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend&start_line=1658&end_line=1667

import Base

# Records cross_entropy(a, targets), PyTorch's cross_entropy with class
# indices and mean reduction, a rank-0 tensor, from a copy of a's value: a
# must be [rows, columns] logits and `targets` one class below `columns`
# per row. The log_softmax lp and the one-hot rows of the targets are saved
# for the VJP. Logits of another rank are refused with NotLogits (107),
# targets that do not fit with TargetOutOfRange (108), an unknown id with
# UnknownNode; the tape comes back unchanged.
def cross_entropy(tape: Tape, +a: Nat, +targets: List<&2, U32>) -> Tape & Result<&2, &2, Error, Nat>:
  Tape{entries} = tape
  entropy_found(a, targets, value_counted(a, counted(entries)))

Uses (10):
  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=Base/base.bend&name=Result
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend&name=Error
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend&name=Tape
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend&name=counted
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend&name=entropy_found
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend&name=value_counted