56 lines
1.3 KiB
Python
56 lines
1.3 KiB
Python
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from django.db.models import FloatField, Func, Value
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from ..utils import Vector, HalfVector, SparseVector
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class DistanceBase(Func):
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output_field = FloatField()
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def __init__(self, expression, vector, **extra):
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if not hasattr(vector, 'resolve_expression'):
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if isinstance(vector, HalfVector):
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vector = Value(HalfVector._to_db(vector))
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elif isinstance(vector, SparseVector):
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vector = Value(SparseVector._to_db(vector))
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else:
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vector = Value(Vector._to_db(vector))
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super().__init__(expression, vector, **extra)
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class BitDistanceBase(Func):
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output_field = FloatField()
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def __init__(self, expression, vector, **extra):
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if not hasattr(vector, 'resolve_expression'):
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vector = Value(vector)
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super().__init__(expression, vector, **extra)
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class L2Distance(DistanceBase):
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function = ''
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arg_joiner = ' <-> '
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class MaxInnerProduct(DistanceBase):
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function = ''
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arg_joiner = ' <#> '
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class CosineDistance(DistanceBase):
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function = ''
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arg_joiner = ' <=> '
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class L1Distance(DistanceBase):
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function = ''
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arg_joiner = ' <+> '
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class HammingDistance(BitDistanceBase):
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function = ''
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arg_joiner = ' <~> '
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class JaccardDistance(BitDistanceBase):
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function = ''
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arg_joiner = ' <%%> '
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