9effd64290
* core, eth, trie: bloom filter for trie node dedup during fast sync * eth/downloader, trie: address review comments * core, ethdb, trie: restart fast-sync bloom construction now and again * eth/downloader: initialize fast sync bloom on startup * eth: reenable eth/62 until we properly remove it
83 lines
2.8 KiB
Markdown
83 lines
2.8 KiB
Markdown
[](https://godoc.org/github.com/steakknife/hamming) [](https://travis-ci.org/steakknife/hamming)
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# hamming distance calculations in Go
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Copyright © 2014, 2015, 2016, 2018 Barry Allard
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[MIT license](MIT-LICENSE.txt)
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## Performance
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```
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$ go test -bench=.
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BenchmarkCountBitsInt8PopCnt-4 300000000 4.30 ns/op
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BenchmarkCountBitsInt16PopCnt-4 300000000 3.83 ns/op
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BenchmarkCountBitsInt32PopCnt-4 300000000 3.64 ns/op
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BenchmarkCountBitsInt64PopCnt-4 500000000 3.60 ns/op
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BenchmarkCountBitsIntPopCnt-4 300000000 5.72 ns/op
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BenchmarkCountBitsUint8PopCnt-4 1000000000 2.98 ns/op
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BenchmarkCountBitsUint16PopCnt-4 500000000 3.23 ns/op
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BenchmarkCountBitsUint32PopCnt-4 500000000 3.00 ns/op
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BenchmarkCountBitsUint64PopCnt-4 1000000000 2.94 ns/op
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BenchmarkCountBitsUintPopCnt-4 300000000 5.04 ns/op
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BenchmarkCountBitsBytePopCnt-4 300000000 3.99 ns/op
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BenchmarkCountBitsRunePopCnt-4 300000000 3.83 ns/op
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BenchmarkCountBitsInt8-4 2000000000 0.74 ns/op
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BenchmarkCountBitsInt16-4 2000000000 1.54 ns/op
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BenchmarkCountBitsInt32-4 1000000000 2.63 ns/op
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BenchmarkCountBitsInt64-4 1000000000 2.56 ns/op
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BenchmarkCountBitsInt-4 200000000 7.23 ns/op
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BenchmarkCountBitsUint16-4 2000000000 1.51 ns/op
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BenchmarkCountBitsUint32-4 500000000 4.00 ns/op
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BenchmarkCountBitsUint64-4 1000000000 2.64 ns/op
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BenchmarkCountBitsUint64Alt-4 200000000 7.60 ns/op
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BenchmarkCountBitsUint-4 300000000 5.48 ns/op
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BenchmarkCountBitsUintReference-4 100000000 19.2 ns/op
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BenchmarkCountBitsByte-4 2000000000 0.75 ns/op
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BenchmarkCountBitsByteAlt-4 1000000000 2.37 ns/op
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BenchmarkCountBitsRune-4 500000000 2.85 ns/op
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PASS
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ok _/Users/bmf/Projects/hamming 58.305s
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$
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```
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## Usage
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```go
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import 'github.com/steakknife/hamming'
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// ...
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// hamming distance between values
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hamming.Byte(0xFF, 0x00) // 8
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hamming.Byte(0x00, 0x00) // 0
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// just count bits in a byte
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hamming.CountBitsByte(0xA5), // 4
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```
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See help in the [docs](https://godoc.org/github.com/steakknife/hamming)
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## Get
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go get -u github.com/steakknife/hamming # master is always stable
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## Source
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- On the web: https://github.com/steakknife/hamming
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- Git: `git clone https://github.com/steakknife/hamming`
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## Contact
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- [Feedback](mailto:barry.allard@gmail.com)
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- [Issues](https://github.com/steakknife/hamming/issues)
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## License
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[MIT license](MIT-LICENSE.txt)
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Copyright © 2014, 2015, 2016 Barry Allard
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