此项目用来对中文文档计算出对应的 simhash 值。 simhash 是谷歌用来进行文本去重的算法，现在广泛应用在文本处理中。
- 使用 CppJieba 作为分词器和关键词抽取器
- 使用 jenkins 作为 hash 函数
hpp风格，所有源码都是.hpp文件里面，方便使用。没有链接，就没有伤害。- 本项目的副产品项目：simhash_server 提供了简单的 simhash HTTP 服务。
- g++ (version >= 4.1 recommended), or clang++ .
git clone --recurse-submodules https://github.com/yanyiwu/simhash.git
cd simhash
mkdir build
cd build
cmake ..
make测试
make test
文本："我是蓝翔技工拖拉机学院手扶拖拉机专业的。不用多久，我就会升职加薪，当上总经理，出任CEO，走上人生巅峰。"
关键词序列是: ["蓝翔:11.7392", "CEO:11.7392", "升职:10.8562", "加薪:10.6426", "手扶拖拉机:10.0089"]
simhash值是: 17831459094038722629
100010110110和110001110011 simhash值的相等判断如下：
海明距离阈值默认设置为3，则isEqual结果为：0
海明距离阈值默认设置为5，则isEqual结果为：1
详情请看 demo
./benchmark/benchmarking结果如下:
Running ./benchmark/benchmarking
Run on (16 X 2494.14 MHz CPU s)
CPU Caches:
L1 Data 32 KiB (x16)
L1 Instruction 32 KiB (x16)
L2 Unified 4096 KiB (x16)
L3 Unified 36608 KiB (x1)
Load Average: 0.07, 0.04, 0.03
***WARNING*** Library was built as DEBUG. Timings may be affected.
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Benchmark Time CPU Iterations
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BENCHMARK_Simhasher_extract_text50_top5 13478 ns 13478 ns 52013
BENCHMARK_Simhasher_extract_text50_top10 13843 ns 13843 ns 50833
BENCHMARK_Simhasher_extract_text50_top15 13929 ns 13929 ns 49488
BENCHMARK_Simhasher_extract_text50_top20 13842 ns 13842 ns 50541
BENCHMARK_Simhasher_extract_text500_top5 184074 ns 184067 ns 3775
BENCHMARK_Simhasher_make_text50_top5 14457 ns 14457 ns 48341
BENCHMARK_Simhasher_make_text50_top10 15170 ns 15169 ns 46203
BENCHMARK_Simhasher_make_text50_top15 15585 ns 15585 ns 44903
BENCHMARK_Simhasher_make_text50_top20 15743 ns 15742 ns 44466
BENCHMARK_Simhasher_binaryStringToUint64 0.000 ns 0.000 ns 1000000000
BENCHMARK_Simhasher_toBinaryString 63.9 ns 63.9 ns 10937009
BENCHMARK_Simhasher_make_from_predefined_keywords5 423 ns 423 ns 1644823
BENCHMARK_Simhasher_make_from_predefined_keywords10 735 ns 735 ns 950156
BENCHMARK_Simhasher_make_from_predefined_keywords20 1364 ns 1364 ns 508935
BENCHMARK_Simhasher_make_from_predefined_keywords50 7876 ns 7875 ns 89006
BENCHMARK_Simhasher_make_from_predefined_keywords100 21409 ns 21409 ns 32743
BENCHMARK_Simhasher_make_from_predefined_keywords200 47469 ns 47468 ns 14728
BENCHMARK_Simhasher_make_from_predefined_keywords500 124316 ns 124314 ns 5627
BENCHMARK_Simhasher_make_from_predefined_keywords1000 251336 ns 251329 ns 2785
BENCHMARK_Simhasher_binaryStringToUint64_isEqual 0.000 ns 0.000 ns 1000000000
BENCHMARK_Simhasher_binaryStringToUint64_isEqual_10k 0.000 ns 0.000 ns 1000000000
BENCHMARK_Simhasher_binaryStringToUint64_isEqual_1000k 0.000 ns 0.000 ns 1000000000