ReduceLAWS.reduce_shape_error: law of bendtorch-core@0.1.0.0
Import: import bendtorch-core@0.1.0.0/src/autograd/reduce_LAWS.bend as ReduceLAWS
Lines 152-161 of bendtorch-core@0.1.0.0/src/autograd/reduce_LAWS.bend: https://jend.leeeet.dev/read.txt?path=bendtorch-core@0.1.0.0/src/autograd/reduce_LAWS.bend&start_line=152&end_line=161

import Base
import bendtorch-core@0.1.0.0/src/shape/core.bend as Shape
import bendtorch-core@0.1.0.0/src/tensor/core.bend as Core
import bendtorch-core@0.1.0.0/src/tensor/elementwise_totality.bend as Totality
import bendtorch-core@0.1.0.0/src/autograd/reduce.bend as Reduce

# When the broadcast planner rejects the target and contribution shapes,
# reduce_to fails with exactly that planner error and returns the contribution
# owner. For example [2] to [0] fails with IncompatibleBroadcast instead of
# returning an empty tensor.
law reduce_shape_error:
  for input: Core.Dynamic
  for +target: Shape.Shape
  for error: Shape.Error
  for rejected: {Shape.broadcast_checked(target, Totality.dynamic_shape(input)) == Fail{error} : Result<&2, &2, Shape.Error, Shape.BroadcastPlan>}
  {Reduce.reduce_to(input, target) == (input, Fail{Reduce.TensorError{Core.ShapeError{error}}}) : Core.Dynamic & Result<&2, &1, Reduce.Error, Core.Dynamic>}

Uses (14):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.sym
  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=Sigma
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/reduce.bend&name=Error
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/reduce.bend&name=planned
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/reduce.bend&name=reduce_to
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/shape/core.bend&name=BroadcastPlan
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/shape/core.bend&name=Error
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/shape/core.bend&name=Shape
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/shape/core.bend&name=broadcast_checked
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/tensor/core.bend&name=Dynamic
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/tensor/core.bend&name=Error
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/tensor/elementwise_totality.bend&name=dynamic_shape