{"id":575,"date":"2016-10-31T12:39:50","date_gmt":"2016-10-31T12:39:50","guid":{"rendered":"http:\/\/pi2e.ch\/blog\/?p=575"},"modified":"2017-03-02T18:58:11","modified_gmt":"2017-03-02T18:58:11","slug":"hexadecimal-digits-of-pi","status":"publish","type":"post","link":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/","title":{"rendered":"Hexadecimal Digits are Correct"},"content":{"rendered":"<p>This week I&#8217;m attending a conference in Strasbourg. While following the opening plenary, I log in to the server, on which my world record computation of pi is running. My interest in the ongoing presentation diminishes rapidly, when I realise that the computation of the hexadecimal digits of pi finished yesterday. Now it will turn out, whether the computation was correct or whether an <a href=\"http:\/\/www.numberworld.org\/y-cruncher\/guides\/swapmode.html#undetected_errors\">undetected error<\/a>, e.g. in the massive disk I\/O, spoiled the computation. Y-Cruncher has built-in redundancy checks, but there is still a chance for a computation to end with a wrong result. In this case, the work of the last three months was a waste of time.<\/p>\n<h5>Bellard&#8217;s formula for the n-th hexadecimal digit of pi<\/h5>\n<div>\n<figure id=\"attachment_581\" aria-describedby=\"caption-attachment-581\" style=\"width: 312px\" class=\"wp-caption alignright\"><a href=\"https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/bellard.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-581\" src=\"https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/bellard.png\" alt=\"bellard\" width=\"312\" height=\"610\" \/><\/a><figcaption id=\"caption-attachment-581\" class=\"wp-caption-text\">Computation of the last hexadecimal digits using Bellard&#8217;s formula.<\/figcaption><\/figure>\n<p>To verify the correctness of the hexadecimal digits of pi, y-cruncher implements <a href=\"https:\/\/en.wikipedia.org\/wiki\/Bellard%27s_formula\">Bellard&#8217;s formula<\/a>. This equation can be used to compute the n-th hexadecimal digit of\u00a0\u03c0<span hidden=\"hidden\">Pi<\/span> without the need of computing the preceding digits. The formula is a variant of the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Bailey%E2%80%93Borwein%E2%80%93Plouffe_formula\">Bailey-Borwein-Plouffe formula<\/a>, which was discovered in 1995. The calculation requires much less resources than the full computation, so I could run it in June even before the 144 TB storage was ready. The algorithm run for one day and computed the 32 hexadecimal digits of pi starting at an offset of 18&#8217;651&#8217;926&#8217;753 001 to be <strong>35ef47c8 a29c2134 291e3f97 0403383d<\/strong>.<\/p>\n<\/div>\n<p>&nbsp;<\/p>\n<h5>Verification of the hexadecimal digits of pi<\/h5>\n<p>After having compiled y-cruncher&#8217;s <a href=\"https:\/\/github.com\/Mysticial\/DigitViewer\">digit viewer<\/a>, I&#8217;m in the position to extract the last hexadecimal digits of the full computation. On my screen, the following numbers appear:<\/p>\n<p><a href=\"https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/verification.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-577 size-full\" src=\"https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/verification.png\" alt=\"last hexadecimal digits of pi\" width=\"382\" height=\"166\" srcset=\"https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/verification.png 382w, https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/verification-300x130.png 300w\" sizes=\"auto, (max-width: 382px) 100vw, 382px\" \/><\/a><\/p>\n<div><\/div>\n<div>Indeed, these are the same digits as computed with Bellards&#8217;s formula. Thanks to God, the two results agree! I&#8217;m relieved that all the effort was not in vain. Now, the computation can enter its final stage: the conversion of the hexadecimal to decimal digits. If you are interested to get a copy of the full 18.6 trillion hexadecimal digits of pi, feel free to <a href=\"https:\/\/pi2e.ch\/blog\/contact\/\">contact <\/a>me.<\/div>\n","protected":false},"excerpt":{"rendered":"<p class=\"post-excerpt\">This week I&#8217;m attending a conference in Strasbourg. While following the opening plenary, I log in to the server, on&#8230;<\/p>\n","protected":false},"author":1,"featured_media":602,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[5,4],"class_list":["post-575","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-math","tag-world-record"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.4 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>18.6 trillion hexadecimal digits of pi verified with Bellard&#039;s formula<\/title>\n<meta name=\"description\" content=\"The hexadecimal digits of pi of my world record computation pass the verification.with Bellard&#039;s formula. To get a copy of the digits, please contact me.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"18.6 trillion hexadecimal digits of pi verified with Bellard&#039;s formula\" \/>\n<meta property=\"og:description\" content=\"The hexadecimal digits of pi of my world record computation pass the verification.with Bellard&#039;s formula. To get a copy of the digits, please contact me.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/\" \/>\n<meta property=\"og:site_name\" content=\"22.4 trillion digits of pi\" \/>\n<meta property=\"article:published_time\" content=\"2016-10-31T12:39:50+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2017-03-02T18:58:11+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/correct.jpeg\" \/>\n\t<meta property=\"og:image:width\" content=\"600\" \/>\n\t<meta property=\"og:image:height\" content=\"346\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"Pipi\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Pipi\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/\"},\"author\":{\"name\":\"Pipi\",\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/#\\\/schema\\\/person\\\/b90b79010da70988fc7dbd995a7db7b3\"},\"headline\":\"Hexadecimal Digits are Correct\",\"datePublished\":\"2016-10-31T12:39:50+00:00\",\"dateModified\":\"2017-03-02T18:58:11+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/\"},\"wordCount\":348,\"image\":{\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/wp-content\\\/uploads\\\/2016\\\/10\\\/correct.jpeg\",\"keywords\":[\"Math\",\"World Record\"],\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/\",\"url\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/\",\"name\":\"18.6 trillion hexadecimal digits of pi verified with Bellard's formula\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/wp-content\\\/uploads\\\/2016\\\/10\\\/correct.jpeg\",\"datePublished\":\"2016-10-31T12:39:50+00:00\",\"dateModified\":\"2017-03-02T18:58:11+00:00\",\"author\":{\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/#\\\/schema\\\/person\\\/b90b79010da70988fc7dbd995a7db7b3\"},\"description\":\"The hexadecimal digits of pi of my world record computation pass the verification.with Bellard's formula. To get a copy of the digits, please contact me.\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/#primaryimage\",\"url\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/wp-content\\\/uploads\\\/2016\\\/10\\\/correct.jpeg\",\"contentUrl\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/wp-content\\\/uploads\\\/2016\\\/10\\\/correct.jpeg\",\"width\":600,\"height\":346},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/2016\\\/10\\\/31\\\/hexadecimal-digits-of-pi\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Hexadecimal Digits are Correct\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/#website\",\"url\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/\",\"name\":\"22.4 trillion digits of pi\",\"description\":\"world record computation of pi\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/pi2e.ch\\\/blog\\\/#\\\/schema\\\/person\\\/b90b79010da70988fc7dbd995a7db7b3\",\"name\":\"Pipi\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/db2d62661a010348e1ed410cbc3ab0265649cb987f220b0b88fbf9387327af85?s=96&d=mm&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/db2d62661a010348e1ed410cbc3ab0265649cb987f220b0b88fbf9387327af85?s=96&d=mm&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/db2d62661a010348e1ed410cbc3ab0265649cb987f220b0b88fbf9387327af85?s=96&d=mm&r=g\",\"caption\":\"Pipi\"}}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"18.6 trillion hexadecimal digits of pi verified with Bellard's formula","description":"The hexadecimal digits of pi of my world record computation pass the verification.with Bellard's formula. To get a copy of the digits, please contact me.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/","og_locale":"en_US","og_type":"article","og_title":"18.6 trillion hexadecimal digits of pi verified with Bellard's formula","og_description":"The hexadecimal digits of pi of my world record computation pass the verification.with Bellard's formula. To get a copy of the digits, please contact me.","og_url":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/","og_site_name":"22.4 trillion digits of pi","article_published_time":"2016-10-31T12:39:50+00:00","article_modified_time":"2017-03-02T18:58:11+00:00","og_image":[{"width":600,"height":346,"url":"https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/correct.jpeg","type":"image\/jpeg"}],"author":"Pipi","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Pipi","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/#article","isPartOf":{"@id":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/"},"author":{"name":"Pipi","@id":"https:\/\/pi2e.ch\/blog\/#\/schema\/person\/b90b79010da70988fc7dbd995a7db7b3"},"headline":"Hexadecimal Digits are Correct","datePublished":"2016-10-31T12:39:50+00:00","dateModified":"2017-03-02T18:58:11+00:00","mainEntityOfPage":{"@id":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/"},"wordCount":348,"image":{"@id":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/#primaryimage"},"thumbnailUrl":"https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/correct.jpeg","keywords":["Math","World Record"],"inLanguage":"en-US"},{"@type":"WebPage","@id":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/","url":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/","name":"18.6 trillion hexadecimal digits of pi verified with Bellard's formula","isPartOf":{"@id":"https:\/\/pi2e.ch\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/#primaryimage"},"image":{"@id":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/#primaryimage"},"thumbnailUrl":"https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/correct.jpeg","datePublished":"2016-10-31T12:39:50+00:00","dateModified":"2017-03-02T18:58:11+00:00","author":{"@id":"https:\/\/pi2e.ch\/blog\/#\/schema\/person\/b90b79010da70988fc7dbd995a7db7b3"},"description":"The hexadecimal digits of pi of my world record computation pass the verification.with Bellard's formula. To get a copy of the digits, please contact me.","breadcrumb":{"@id":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/#primaryimage","url":"https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/correct.jpeg","contentUrl":"https:\/\/pi2e.ch\/blog\/wp-content\/uploads\/2016\/10\/correct.jpeg","width":600,"height":346},{"@type":"BreadcrumbList","@id":"https:\/\/pi2e.ch\/blog\/2016\/10\/31\/hexadecimal-digits-of-pi\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/pi2e.ch\/blog\/"},{"@type":"ListItem","position":2,"name":"Hexadecimal Digits are Correct"}]},{"@type":"WebSite","@id":"https:\/\/pi2e.ch\/blog\/#website","url":"https:\/\/pi2e.ch\/blog\/","name":"22.4 trillion digits of pi","description":"world record computation of pi","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/pi2e.ch\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/pi2e.ch\/blog\/#\/schema\/person\/b90b79010da70988fc7dbd995a7db7b3","name":"Pipi","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/db2d62661a010348e1ed410cbc3ab0265649cb987f220b0b88fbf9387327af85?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/db2d62661a010348e1ed410cbc3ab0265649cb987f220b0b88fbf9387327af85?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/db2d62661a010348e1ed410cbc3ab0265649cb987f220b0b88fbf9387327af85?s=96&d=mm&r=g","caption":"Pipi"}}]}},"_links":{"self":[{"href":"https:\/\/pi2e.ch\/blog\/wp-json\/wp\/v2\/posts\/575","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pi2e.ch\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pi2e.ch\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pi2e.ch\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pi2e.ch\/blog\/wp-json\/wp\/v2\/comments?post=575"}],"version-history":[{"count":42,"href":"https:\/\/pi2e.ch\/blog\/wp-json\/wp\/v2\/posts\/575\/revisions"}],"predecessor-version":[{"id":697,"href":"https:\/\/pi2e.ch\/blog\/wp-json\/wp\/v2\/posts\/575\/revisions\/697"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pi2e.ch\/blog\/wp-json\/wp\/v2\/media\/602"}],"wp:attachment":[{"href":"https:\/\/pi2e.ch\/blog\/wp-json\/wp\/v2\/media?parent=575"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pi2e.ch\/blog\/wp-json\/wp\/v2\/categories?post=575"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pi2e.ch\/blog\/wp-json\/wp\/v2\/tags?post=575"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}