plugeth/vendor/github.com/steakknife/hamming/README.md
Péter Szilágyi 9effd64290
core, eth, trie: bloom filter for trie node dedup during fast sync (#19489)
* 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
2019-05-13 15:28:01 +03:00

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hamming distance calculations in Go

Copyright © 2014, 2015, 2016, 2018 Barry Allard

MIT license

Performance

$ go test -bench=.
BenchmarkCountBitsInt8PopCnt-4      	300000000	         4.30 ns/op
BenchmarkCountBitsInt16PopCnt-4     	300000000	         3.83 ns/op
BenchmarkCountBitsInt32PopCnt-4     	300000000	         3.64 ns/op
BenchmarkCountBitsInt64PopCnt-4     	500000000	         3.60 ns/op
BenchmarkCountBitsIntPopCnt-4       	300000000	         5.72 ns/op
BenchmarkCountBitsUint8PopCnt-4     	1000000000	         2.98 ns/op
BenchmarkCountBitsUint16PopCnt-4    	500000000	         3.23 ns/op
BenchmarkCountBitsUint32PopCnt-4    	500000000	         3.00 ns/op
BenchmarkCountBitsUint64PopCnt-4    	1000000000	         2.94 ns/op
BenchmarkCountBitsUintPopCnt-4      	300000000	         5.04 ns/op
BenchmarkCountBitsBytePopCnt-4      	300000000	         3.99 ns/op
BenchmarkCountBitsRunePopCnt-4      	300000000	         3.83 ns/op
BenchmarkCountBitsInt8-4            	2000000000	         0.74 ns/op
BenchmarkCountBitsInt16-4           	2000000000	         1.54 ns/op
BenchmarkCountBitsInt32-4           	1000000000	         2.63 ns/op
BenchmarkCountBitsInt64-4           	1000000000	         2.56 ns/op
BenchmarkCountBitsInt-4             	200000000	         7.23 ns/op
BenchmarkCountBitsUint16-4          	2000000000	         1.51 ns/op
BenchmarkCountBitsUint32-4          	500000000	         4.00 ns/op
BenchmarkCountBitsUint64-4          	1000000000	         2.64 ns/op
BenchmarkCountBitsUint64Alt-4       	200000000	         7.60 ns/op
BenchmarkCountBitsUint-4            	300000000	         5.48 ns/op
BenchmarkCountBitsUintReference-4   	100000000	        19.2 ns/op
BenchmarkCountBitsByte-4            	2000000000	         0.75 ns/op
BenchmarkCountBitsByteAlt-4         	1000000000	         2.37 ns/op
BenchmarkCountBitsRune-4            	500000000	         2.85 ns/op
PASS
ok  	_/Users/bmf/Projects/hamming	58.305s
$

Usage

import 'github.com/steakknife/hamming'

// ...

// hamming distance between values
hamming.Byte(0xFF, 0x00) // 8
hamming.Byte(0x00, 0x00) // 0

// just count bits in a byte
hamming.CountBitsByte(0xA5), // 4

See help in the docs

Get

go get -u github.com/steakknife/hamming  # master is always stable

Source

Contact

License

MIT license

Copyright © 2014, 2015, 2016 Barry Allard