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Fix mixture weights in fine_tune

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Matthew Honnibal 2017-08-14 17:55:18 -05:00
parent 335fa8b05c
commit 6259490347
1 changed files with 12 additions and 8 deletions
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20
spacy/_ml.py
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@ -372,21 +372,25 @@ def fine_tune(embedding, combine=None):
vecs, bp_vecs = embedding.begin_update(docs, drop=drop) vecs, bp_vecs = embedding.begin_update(docs, drop=drop)
flat_tokvecs = embedding.ops.flatten(tokvecs) flat_tokvecs = embedding.ops.flatten(tokvecs)
flat_vecs = embedding.ops.flatten(vecs) flat_vecs = embedding.ops.flatten(vecs)
alpha = model.mix
minus = 1-model.mix
output = embedding.ops.unflatten( output = embedding.ops.unflatten(
(model.mix[0] * flat_vecs + model.mix[1] * flat_tokvecs), (alpha * flat_tokvecs + minus * flat_vecs), lengths)
lengths)
def fine_tune_bwd(d_output, sgd=None): def fine_tune_bwd(d_output, sgd=None):
bp_vecs([d_o * model.d_mix[0] for d_o in d_output], sgd=sgd)
flat_grad = model.ops.flatten(d_output) flat_grad = model.ops.flatten(d_output)
model.d_mix[1] += flat_tokvecs.dot(flat_grad.T).sum() model.d_mix += flat_tokvecs.dot(flat_grad.T).sum()
model.d_mix[0] += flat_vecs.dot(flat_grad.T).sum() model.d_mix += 1-flat_vecs.dot(flat_grad.T).sum()
bp_vecs([d_o * minus for d_o in d_output], sgd=sgd)
d_output = [d_o * alpha for d_o in d_output]
sgd(model._mem.weights, model._mem.gradient, key=model.id) sgd(model._mem.weights, model._mem.gradient, key=model.id)
return [d_o * model.d_mix[1] for d_o in d_output] model.mix = model.ops.xp.minimum(model.mix, 1.0)
return d_output
return output, fine_tune_bwd return output, fine_tune_bwd
model = wrap(fine_tune_fwd, embedding) model = wrap(fine_tune_fwd, embedding)
model.mix = model._mem.add((model.id, 'mix'), (2,)) model.mix = model._mem.add((model.id, 'mix'), (1,))
model.mix.fill(0.5) model.mix.fill(0.0)
model.d_mix = model._mem.add_gradient((model.id, 'd_mix'), (model.id, 'mix')) model.d_mix = model._mem.add_gradient((model.id, 'd_mix'), (model.id, 'mix'))
return model return model