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124 lines
3.7 KiB
124 lines
3.7 KiB
from typing import Callable, cast
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import numpy
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from .backends import Ops
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from .config import registry
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from .types import FloatsXd, Shape
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from .util import partial
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# TODO: Harmonize naming with Keras, and fill in missing entries
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# https://keras.io/initializers/ We should also have He normal/uniform
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# and probably lecun normal/uniform.
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# Initialize via numpy, before copying to ops. This makes it easier to work with
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# the different backends, because the backend won't affect the randomization.
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def lecun_normal_init(ops: Ops, shape: Shape) -> FloatsXd:
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scale = numpy.sqrt(1.0 / shape[1])
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return ops.asarray_f(cast(FloatsXd, numpy.random.normal(0, scale, shape)))
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@registry.initializers("lecun_normal_init.v1")
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def configure_lecun_normal_init() -> Callable[[Shape], FloatsXd]:
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return partial(lecun_normal_init)
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def he_normal_init(ops: Ops, shape: Shape) -> FloatsXd:
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scale = numpy.sqrt(2.0 / shape[1])
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return ops.asarray_f(cast(FloatsXd, numpy.random.normal(0, scale, shape)))
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@registry.initializers("he_normal_init.v1")
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def configure_he_normal_init() -> Callable[[Shape], FloatsXd]:
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return partial(he_normal_init)
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def glorot_normal_init(ops: Ops, shape: Shape) -> FloatsXd:
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scale = numpy.sqrt(2.0 / (shape[1] + shape[0]))
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return ops.asarray_f(cast(FloatsXd, numpy.random.normal(0, scale, shape)))
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@registry.initializers("glorot_normal_init.v1")
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def configure_glorot_normal_init() -> Callable[[Shape], FloatsXd]:
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return partial(glorot_normal_init)
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def he_uniform_init(ops: Ops, shape: Shape) -> FloatsXd:
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scale = numpy.sqrt(6.0 / shape[1])
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return ops.asarray_f(cast(FloatsXd, numpy.random.uniform(-scale, scale, shape)))
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@registry.initializers("he_uniform_init.v1")
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def configure_he_uniform_init() -> Callable[[Shape], FloatsXd]:
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return partial(he_uniform_init)
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def lecun_uniform_init(ops: Ops, shape: Shape) -> FloatsXd:
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scale = numpy.sqrt(3.0 / shape[1])
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return ops.asarray_f(cast(FloatsXd, numpy.random.uniform(-scale, scale, shape)))
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@registry.initializers("lecun_uniform_init.v1")
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def configure_lecun_uniform_init() -> Callable[[Shape], FloatsXd]:
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return partial(lecun_uniform_init)
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def glorot_uniform_init(ops: Ops, shape: Shape) -> FloatsXd:
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scale = numpy.sqrt(6.0 / (shape[0] + shape[1]))
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return ops.asarray_f(cast(FloatsXd, numpy.random.uniform(-scale, scale, shape)))
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@registry.initializers("glorot_uniform_init.v1")
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def configure_glorot_uniform_init() -> Callable[[Shape], FloatsXd]:
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return partial(glorot_uniform_init)
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def zero_init(ops: Ops, shape: Shape) -> FloatsXd:
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return ops.alloc_f(shape)
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@registry.initializers("zero_init.v1")
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def configure_zero_init() -> Callable[[FloatsXd], FloatsXd]:
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return partial(zero_init)
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def uniform_init(
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ops: Ops, shape: Shape, *, lo: float = -0.1, hi: float = 0.1
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) -> FloatsXd:
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values = numpy.random.uniform(lo, hi, shape)
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return ops.asarray_f(cast(FloatsXd, values.astype("float32")))
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@registry.initializers("uniform_init.v1")
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def configure_uniform_init(
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*, lo: float = -0.1, hi: float = 0.1
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) -> Callable[[FloatsXd], FloatsXd]:
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return partial(uniform_init, lo=lo, hi=hi)
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def normal_init(ops: Ops, shape: Shape, *, mean: float = 0) -> FloatsXd:
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size = int(ops.xp.prod(ops.xp.asarray(shape)))
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inits = cast(FloatsXd, numpy.random.normal(scale=mean, size=size).astype("float32"))
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inits = ops.reshape_f(inits, shape)
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return ops.asarray_f(inits)
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@registry.initializers("normal_init.v1")
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def configure_normal_init(*, mean: float = 0) -> Callable[[FloatsXd], FloatsXd]:
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return partial(normal_init, mean=mean)
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__all__ = [
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"normal_init",
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"uniform_init",
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"glorot_uniform_init",
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"zero_init",
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"lecun_uniform_init",
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"he_uniform_init",
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"glorot_normal_init",
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"he_normal_init",
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"lecun_normal_init",
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]
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