Wie baut man aus gleichverteilen Zufallszahlen normalverteile?
\nMan nimmt std::normal_distribution<\/p>\n
http:\/\/en.cppreference.com\/w\/cpp\/numeric\/random\/normal_distribution<\/p>\n
Und wie ist das Implementiert? Eine Beispielimplementation gibt es in der gnu stdc++<\/p>\n
https:\/\/gcc.gnu.org\/onlinedocs\/gcc-4.7.4\/libstdc++\/api\/a01267_source.html#l01678<\/p>\n
Wtf? Versteht kein Mesch. Das Paper auf dass die sich beziehen ist auch ein Hammer.<\/p>\n
http:\/\/www.eirene.de\/Devroye.pdf Seite 249<\/p>\n
Hier die Template bereinigte Version vom GNU<\/p>\n
\r\n#include <iostream>\r\n#include <iomanip>\r\n#include <string>\r\n#include <map>\r\n#include <random>\r\n#include <cmath>\r\n\r\ndouble round(double x) {\r\n return int(x*10)\/10.0;\r\n}\r\n\r\n\/\/ erzeugt gleichverteilte zufallzahlen im interfall [0:1]\r\nstruct uniform_real_random_device {\r\n std::mt19937 gen;\r\n std::uniform_real_distribution<> uniform_dist = std::uniform_real_distribution<>(0.0, 1.0);\r\n\r\n double operator() () {\r\n return uniform_dist(gen);\r\n }\r\n};\r\n\r\n\/**\r\n * Polar method due to Marsaglia.\r\n *\r\n * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,\r\n * New York, 1986, Ch. V, Sect. 4.4.\r\n *\r\n * https:\/\/gcc.gnu.org\/onlinedocs\/gcc-4.7.4\/libstdc++\/api\/a01267_source.html#l01678\r\n *\/\r\ndouble normal_dist(uniform_real_random_device& rand, double mean, double stddev) {\r\n double x, y, r2;\r\n do\r\n {\r\n x = 2.0 * rand() - 1.0;\r\n y = 2.0 * rand() - 1.0;\r\n r2 = x * x + y * y;\r\n }\r\n while (r2 > 1.0 || r2 == 0.0);\r\n\r\n double mult = std::sqrt(-2 * std::log(r2) \/ r2);\r\n double result = y * mult;\r\n result = result*stddev + mean;\r\n return result;\r\n}\r\n\r\nint main() {\r\n uniform_real_random_device uniformRand;\r\n\r\n std::map hist;\r\n for(int n=0; n<100000; ++n) {\r\n double gaussZahle = normal_dist(uniformRand, 0.5, 0.5);\r\n ++hist[round(gaussZahle)];\r\n }\r\n\r\n \/\/ ausgabe\r\n for(auto p : hist) {\r\n std::cout << std::fixed << std::setprecision(1) << std::setw(2)\r\n << p.first << ' ' << std::string(p.second\/100, '*') << '\\n';\r\n }\r\n}\r\n<\/code><\/pre>\n\n-1.5
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Jaaa da ist noch ein Bug drin bei der 0. Wer ihn findet, darf mir eine Mail schreiben.<\/p>\n","protected":false},"excerpt":{"rendered":"
Wie baut man aus gleichverteilen Zufallszahlen normalverteile? Man nimmt std::normal_distribution http:\/\/en.cppreference.com\/w\/cpp\/numeric\/random\/normal_distribution Und wie ist das Implementiert? Eine Beispielimplementation gibt es in der gnu stdc++ https:\/\/gcc.gnu.org\/onlinedocs\/gcc-4.7.4\/libstdc++\/api\/a01267_source.html#l01678 Wtf? Versteht kein Mesch. Das Paper auf dass die sich beziehen ist auch ein Hammer. http:\/\/www.eirene.de\/Devroye.pdf Seite 249 Hier die Template bereinigte Version vom GNU #include <iostream> #include <iomanip> #include […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[17],"class_list":["post-2455","post","type-post","status-publish","format-standard","hentry","category-allgemein","tag-cpp"],"_links":{"self":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/2455","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2455"}],"version-history":[{"count":3,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/2455\/revisions"}],"predecessor-version":[{"id":2458,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/2455\/revisions\/2458"}],"wp:attachment":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2455"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2455"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2455"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}