Tensor.narrow_bwd: def of bendtorch@1.3.0.0
Import: import bendtorch@1.3.0.0/tensor.bend as Tensor
Lines 546-550 of bendtorch@1.3.0.0/tensor.bend: https://jend.leeeet.dev/read.txt?path=bendtorch@1.3.0.0/tensor.bend&start_line=546&end_line=550

import Base

# the gradient of narrow: dy in its window, zeros elsewhere
def narrow_bwd(+s: List<&2, Nat>, +d: Nat, +st: Nat, +l: Nat, dy: Tensor<setd(s, d, l)>) -> TP<setd(s, d, l), s>:
  match dy:
    case Tensor{dd}:
      tp_of(setd(s, d, l), s, place_l(numel(setd(s, d, l)), 0, narrow_map(s, d, st, l), Array.get(F32, dd, 0), new(numel(s))))

Uses (12):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Array.get
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32
  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=bendtorch@1.3.0.0/tensor.bend&name=TP
  https://jend.leeeet.dev/definition.txt?path=bendtorch@1.3.0.0/tensor.bend&name=Tensor
  https://jend.leeeet.dev/definition.txt?path=bendtorch@1.3.0.0/tensor.bend&name=narrow_map
  https://jend.leeeet.dev/definition.txt?path=bendtorch@1.3.0.0/tensor.bend&name=new
  https://jend.leeeet.dev/definition.txt?path=bendtorch@1.3.0.0/tensor.bend&name=numel
  https://jend.leeeet.dev/definition.txt?path=bendtorch@1.3.0.0/tensor.bend&name=place_l
  https://jend.leeeet.dev/definition.txt?path=bendtorch@1.3.0.0/tensor.bend&name=setd
  https://jend.leeeet.dev/definition.txt?path=bendtorch@1.3.0.0/tensor.bend&name=tp_of