31 lines
815 B
Python
31 lines
815 B
Python
from typing import Callable, Tuple, cast
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from ..config import registry
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from ..model import Model
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from ..types import Floats2d, Ragged
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from ..util import ArrayInfo
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InT = Ragged
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OutT = Floats2d
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@registry.layers("reduce_first.v1")
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def reduce_first() -> Model[InT, OutT]:
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"""Reduce ragged-formatted sequences to their first element."""
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return Model("reduce_first", forward)
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def forward(
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model: Model[InT, OutT], Xr: InT, is_train: bool
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) -> Tuple[OutT, Callable[[OutT], InT]]:
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Y, starts_ends = model.ops.reduce_first(cast(Floats2d, Xr.data), Xr.lengths)
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array_info = ArrayInfo.from_array(Y)
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def backprop(dY: OutT) -> InT:
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array_info.check_consistency(dY)
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dX = model.ops.backprop_reduce_first(dY, starts_ends)
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return Ragged(dX, Xr.lengths)
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return Y, backprop
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