TensorBackward.sum_dims: def of bendtorch-core@0.1.0.0
Import: import bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend as TensorBackward
Lines 1412-1421 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=1412&end_line=1421

import Base
import bendtorch-core@0.1.0.0/src/tensor/signed.bend as Signed
import bendtorch-core@0.1.0.0/src/autograd/sum_dims.bend as SumDims

# Records PyTorch's a.sum(dim=axes, keepdim=keepdim), SumDims.sum_dims of a
# copy of a's value: the kept shape when keepdim is True, else the dropped
# one. The axes are PyTorch's signed ones: Last{0} is -1, a's last axis. An
# empty axis list sums every axis. An axis outside -limit..limit-1, where
# limit is max(rank, 1), so a rank-0 a takes -1 and 0, is refused with
# AxisOutOfBounds (13), two axes that name one axis with DuplicateAxis (14),
# an unknown id with UnknownNode; the tape comes back unchanged.
def sum_dims(tape: Tape, +a: Nat, +axes: List<&2, Signed.Position>, keepdim: Bool) -> Tape & Result<&2, &2, Error, Nat>:
  Tape{entries} = tape
  dims_found(a, axes, keepdim, value_counted(a, counted(entries)))

Uses (11):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  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=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=dims_found
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend&name=value_counted
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/tensor/signed.bend&name=Position