101 lines
3.0 KiB
Python
101 lines
3.0 KiB
Python
# Copyright (c) Facebook, Inc. and its affiliates.
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#
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# This source code is licensed under the MIT license found in the
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# LICENSE file in the root directory of this source tree.
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import faiss
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import re
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def get_code_size(d, indexkey):
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""" size of one vector in an index in dimension d
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constructed with factory string indexkey"""
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if indexkey == "Flat":
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return d * 4
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if indexkey.endswith(",RFlat"):
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return d * 4 + get_code_size(d, indexkey[:-len(",RFlat")])
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mo = re.match("IVF\\d+(_HNSW32)?,(.*)$", indexkey)
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if mo:
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return get_code_size(d, mo.group(2))
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mo = re.match("IVF\\d+\\(.*\\)?,(.*)$", indexkey)
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if mo:
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return get_code_size(d, mo.group(1))
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mo = re.match("IMI\\d+x2,(.*)$", indexkey)
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if mo:
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return get_code_size(d, mo.group(1))
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mo = re.match("(.*),Refine\\((.*)\\)$", indexkey)
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if mo:
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return get_code_size(d, mo.group(1)) + get_code_size(d, mo.group(2))
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mo = re.match('PQ(\\d+)x(\\d+)(fs|fsr)?$', indexkey)
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if mo:
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return (int(mo.group(1)) * int(mo.group(2)) + 7) // 8
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mo = re.match('PQ(\\d+)\\+(\\d+)$', indexkey)
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if mo:
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return (int(mo.group(1)) + int(mo.group(2)))
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mo = re.match('PQ(\\d+)$', indexkey)
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if mo:
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return int(mo.group(1))
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if indexkey == "HNSW32" or indexkey == "HNSW32,Flat":
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return d * 4 + 64 * 4 # roughly
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if indexkey == 'SQ8':
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return d
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elif indexkey == 'SQ4':
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return (d + 1) // 2
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elif indexkey == 'SQ6':
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return (d * 6 + 7) // 8
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elif indexkey == 'SQfp16':
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return d * 2
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mo = re.match('PCAR?(\\d+),(.*)$', indexkey)
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if mo:
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return get_code_size(int(mo.group(1)), mo.group(2))
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mo = re.match('OPQ\\d+_(\\d+),(.*)$', indexkey)
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if mo:
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return get_code_size(int(mo.group(1)), mo.group(2))
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mo = re.match('OPQ\\d+,(.*)$', indexkey)
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if mo:
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return get_code_size(d, mo.group(1))
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mo = re.match('RR(\\d+),(.*)$', indexkey)
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if mo:
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return get_code_size(int(mo.group(1)), mo.group(2))
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raise RuntimeError("cannot parse " + indexkey)
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def reverse_index_factory(index):
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"""
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attempts to get the factory string the index was built with
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"""
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index = faiss.downcast_index(index)
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if isinstance(index, faiss.IndexFlat):
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return "Flat"
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if isinstance(index, faiss.IndexIVF):
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quantizer = faiss.downcast_index(index.quantizer)
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if isinstance(quantizer, faiss.IndexFlat):
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prefix = "IVF%d" % index.nlist
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elif isinstance(quantizer, faiss.MultiIndexQuantizer):
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prefix = "IMI%dx%d" % (quantizer.pq.M, quantizer.pq.nbit)
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elif isinstance(quantizer, faiss.IndexHNSW):
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prefix = "IVF%d_HNSW%d" % (index.nlist, quantizer.hnsw.M)
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else:
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prefix = "IVF%d(%s)" % (index.nlist, reverse_index_factory(quantizer))
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if isinstance(index, faiss.IndexIVFFlat):
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return prefix + ",Flat"
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if isinstance(index, faiss.IndexIVFScalarQuantizer):
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return prefix + ",SQ8"
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raise NotImplementedError()
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