{"id":492,"date":"2013-07-21T23:17:19","date_gmt":"2013-07-21T15:17:19","guid":{"rendered":"http:\/\/hymike.net\/blog\/?p=492"},"modified":"2013-07-21T23:17:19","modified_gmt":"2013-07-21T15:17:19","slug":"%e6%b1%89%e6%98%8e%e8%b7%9d%e7%a6%bb%e7%9a%84%e5%bf%ab%e9%80%9f%e8%ae%a1%e7%ae%97%e6%96%b9%e6%b3%95","status":"publish","type":"post","link":"https:\/\/blog.hymike.net\/?p=492","title":{"rendered":"\u6c49\u660e\u8ddd\u79bb\u7684\u5feb\u901f\u8ba1\u7b97\u65b9\u6cd5"},"content":{"rendered":"

\u9996\u5148\uff0c\u6240\u8c13\u6c49\u660e\u8ddd\u79bb\uff0c\u662f\u8bf4\u4e24\u4e2a01\u4e32\u4e4b\u95f4\u4e0d\u76f8\u540c\u76840\u548c1\u7684\u4e2a\u6570\u3002
\n\u6bd4\u5982\uff1a 1 1 0 1 1 \u548c 1 0 1 0 1 \u7684\u6c49\u660e\u8ddd\u79bb\u5c31\u662f3\uff08\u4e2d\u95f4\u4e09\u4f4d\u4e0d\u76f8\u540c\uff09
\n\u90a3\u4e48\uff0c\u600e\u4e48\u5feb\u901f\u8ba1\u7b97\u6c49\u660e\u8ddd\u79bb\u5462\uff1f
\n\u8fd9\u91cc\u7ed9\u51fa\u4e09\u4e2a\u65b9\u6cd5\uff0c\u5747\u4ee5\u4e24\u4e2aunsigned __int64\u7684\u6570a\u548cb\u7684\u6c49\u660e\u8ddd\u79bb\u6765\u505a\u4f8b\u5b50\uff1a<\/p>\n

1\uff09\u53c2\u8003\u6587\u7ae0\uff1ahttp:\/\/crane.is-programmer.com\/posts\/17830.html
\n
\nunsigned __int64 nHammingDist=a^b;<\/p>\n

nHammingDist = (nHammingDist & 0x5555555555555555UI64) + ((nHammingDist>>1) & 0x5555555555555555UI64);
\nnHammingDist = (nHammingDist & 0x3333333333333333UI64) + ((nHammingDist>>2) & 0x3333333333333333UI64);
\nnHammingDist = (nHammingDist & 0x0f0f0f0f0f0f0f0fUI64) + ((nHammingDist>>4) & 0x0f0f0f0f0f0f0f0fUI64);
\nnHammingDist = (nHammingDist & 0x00ff00ff00ff00ffUI64) + ((nHammingDist>>8) & 0x00ff00ff00ff00ffUI64);
\nnHammingDist = (nHammingDist & 0x0000ffff0000ffffUI64) + ((nHammingDist>>16) & 0x0000ffff0000ffffUI64);
\nnHammingDist = (nHammingDist & 0x00000000ffffffffUI64) + ((nHammingDist>>32) & 0x00000000ffffffffUI64);
\n<\/code><\/p>\n

2\uff09\u5982\u679c\u4e0a\u8ff0\u6c49\u660e\u8ddd\u79bb\u9700\u8981\u9891\u7e41\u8ba1\u7b97\uff0c\u90a3\u4e48\uff0c\u6253\u8868\u6cd5\u4e0d\u5931\u4e3a\u4e00\u79cd\u597d\u65b9\u6cd5\u3002\u8003\u8651\u5230\u6253\u8868\u7684\u5927\u5c0f\u8981\u5c3d\u53ef\u80fd\u8d34\u8fd1L1\u7f13\u5b58\u9650\u5236\uff0c\u6240\u4ee5\u8003\u86518bit\u8ba1\u7b97\u4e00\u6b21\uff1a
\n
\nstatic int Ham_count[256]={0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
\n1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
\n1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
\n2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,4,5,5,6,5,6,6,7,5,6,6,7,6,7,7,8};<\/p>\n

unsigned __int64 temp=a^b;
\nuchar *uch=(uchar*)&temp;
\nint i,nHammingDist=0;
\nfor(i=0;i<8;i++)\n{\n\tnHammingDist+=Ham_count[uch[i]];\n}\n<\/code><\/p>\n

3\uff09\u5982\u679cCPU\u652f\u6301sse4.2\u6307\u4ee4\u96c6\u7684\u8bdd\uff0c\u53ef\u4ee5\u7528sse\u6269\u5c55\u6307\u4ee4\u5feb\u901f\u8ba1\u7b97\uff08intel core 2\u4ee5\u4e0aCPU\/amd \u63a8\u571f\u673a\u4ee5\u4e0aCPU\uff09
\n
\n#include \t\/\/\u9700\u8981\u8fd9\u4e2a\u5934\u6587\u4ef6\uff08VS2008\u53ca\u4ee5\u4e0a\u7684VS\u3002gcc\u4e4b\u7c7b\u7684\u4e0d\u6e05\u695a\uff09
\nint nHammingDist=_mm_popcnt_u64(a^b);
\n<\/code><\/p>\n

\u90a3\u4e48\uff0c\u4e0a\u8ff0\u4e09\u79cd\u5feb\u901f\u7b97\u6cd5\u7684\u65f6\u95f4\u4ee3\u4ef7\u5206\u522b\u662f\u591a\u5c11\u5462\uff1f
\n\u6d4b\u8bd5\u65b9\u6cd5\uff1a1,000\u4e2a256bit\u6570\uff0c\u6bcf\u4e2a\u5728100,0000\u4e2a256bit\u6570\u4e2d\u95f4\u627e\u6700\u8fd1\u7684\u90a3\u4e2a\u6570\u3002\u8ba1\u7b97\u603b\u8ba1\u82b1\u8d39\u7684\u65f6\u95f4\u3002\uff08\u5355\u68382.8GHz intel core i5 460m\uff09
\n\u4e0b\u9762\u662f\u5b9e\u9a8c\u7ed3\u679c\uff1a
\n\u65b9\u6cd51: 56s
\n\u65b9\u6cd52: 53s
\n\u65b9\u6cd53: 34s<\/p>\n

\u7531\u6b64\u53ef\u89c1\uff0c\u6253\u8868\u6cd5\u6bd4\u6298\u534a\u8ba1\u7b97\u7a0d\u5feb\uff08\u5b9e\u9645\u5982\u679c\u591a\u7ebf\u7a0b\u540c\u65f6\u5904\u7406\u7684\u8bdd\uff0c\u65b9\u6cd52\u4f1a\u6bd4\u65b9\u6cd51\u5feb10%\u4ee5\u4e0a\uff0c\u56e0\u4e3a\u65b9\u6cd51\u9700\u8981ALU\u8ba1\u7b97\uff0c\u800c\u65b9\u6cd52\u57fa\u672c\u4e0d\u9700\u8981ALU\uff09
\n\u65b9\u6cd53\u7684\u5229\u7528sse4.2\u6307\u4ee4\u7684\u65b9\u6cd5\u662f\u6700\u5feb\u7684\uff0c\u4f46\u9700\u8981CPU\u652f\u6301\uff08\u4e0d\u8fc7\u6309\u7167\u7535\u8111\u6bcf5\u5e74\u5de6\u53f3\u4f1a\u6dd8\u6c70\u4e00\u6b21\u7684\u89d2\u5ea6\u6765\u770b\uff0c\u8fc7\u51e0\u5e74\u5c31\u90fd\u652f\u6301\u4e86\uff09<\/p>\n

\u603b\u7ed3\uff1a\u7b97\u6cd5\u518d\u5feb\uff0c\u4e0d\u5982CPU\u786c\u4ef6\u5b9e\u73b0\u5feb\u2026\u2026<\/p>\n","protected":false},"excerpt":{"rendered":"

\u9996\u5148\uff0c\u6240\u8c13\u6c49\u660e\u8ddd\u79bb\uff0c\u662f\u8bf4\u4e24\u4e2a01\u4e32\u4e4b\u95f4\u4e0d\u76f8\u540c\u76840\u548c1\u7684\u4e2a\u6570\u3002 \u6bd4\u5982\uff1a 1 1 0 1 1 \u548c 1 0 1 0 … \u7ee7\u7eed\u9605\u8bfb\u201c\u6c49\u660e\u8ddd\u79bb\u7684\u5feb\u901f\u8ba1\u7b97\u65b9\u6cd5\u201d<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[4],"tags":[],"_links":{"self":[{"href":"https:\/\/blog.hymike.net\/index.php?rest_route=\/wp\/v2\/posts\/492"}],"collection":[{"href":"https:\/\/blog.hymike.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.hymike.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.hymike.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.hymike.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=492"}],"version-history":[{"count":0,"href":"https:\/\/blog.hymike.net\/index.php?rest_route=\/wp\/v2\/posts\/492\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.hymike.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=492"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.hymike.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=492"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.hymike.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=492"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}