[MRG+1] micro-optimize HashingVectorizer and FeatureHasher #7470
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kmike
commented
Sep 22, 2016
| @@ -45,7 +43,7 @@ def transform(raw_X, Py_ssize_t n_features, dtype): | |||
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| for x in raw_X: | |||
| for f, v in x: | |||
| if isinstance(v, string_types): | |||
| if isinstance(v, basestring): | |||
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This requires Cython 0.20+, is it OK? If not, it is possible to replace it with (str, unicode) which does the same.
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Hmm I'd prefer using (str, unicode). We don't have published "minimum cython requirements" but I suppose there's no harm in this case in maintaining backwards compatibility?
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LGTM |
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thanks |
TomDLT
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Oct 3, 2016
…arn#7470) * micro-optimize HashingVectorizer and FeatureHasher * fix backwards compatibility for Cython < 0.20
Sundrique
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Jun 14, 2017
…arn#7470) * micro-optimize HashingVectorizer and FeatureHasher * fix backwards compatibility for Cython < 0.20
paulha
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Aug 19, 2017
…arn#7470) * micro-optimize HashingVectorizer and FeatureHasher * fix backwards compatibility for Cython < 0.20
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There is a common gotcha in Cython code: even after a type check Cython compiles
txt.encode('utf-8')to a code which looks up 'encode' method, then calls it as a Python method, this method has to find utf-8 codec, etc.On the other hand,
compiles directly to a PyUnicode_AsUTF8String call.
Another gotcha is that if you declare argument type (e.g. bytes) and then pass a variable of type object, it does more work, not less work because type is checked. Because we know a variable is bytes casting it to bytes allow to remove all these type checks and conversions.
The third thing I fixed is
string_typeslookup. "basestring" in Cython is the same as six.string_types; isinstance check gets compiled directly to C API calls this way.These changes allow to make HashingVectorizer about 10% faster. Benchmark script:
For me it runs in 13.8 ms before the changes and 11.5 ms after the changes.
This change is