{"id":298,"date":"2012-07-30T09:44:17","date_gmt":"2012-07-30T09:44:17","guid":{"rendered":"http:\/\/ahay.org\/blog\/?p=298"},"modified":"2015-09-02T21:56:52","modified_gmt":"2015-09-02T21:56:52","slug":"fftw","status":"publish","type":"post","link":"https:\/\/ahay.org\/blog\/2012\/07\/30\/fftw\/","title":{"rendered":"FFTW"},"content":{"rendered":"<p><img decoding=\"async\" src=\"http:\/\/www.fftw.org\/fftw-logo-med.gif\" align=\"left\" \/> <a href=\"http:\/\/www.fftw.org\/\">FFTW<\/a> (the Fastest Fourier Transform in the West) is a famous library implementing an FFT algorithm. It was developed at MIT by <a href=\"http:\/\/www.fftw.org\/~athena\/\">Matteo Frigo<\/a> and <a href=\"http:\/\/math.mit.edu\/~stevenj\/\">Steven G. Johnson<\/a> and is distributed under a GPL license. <\/p>\n<p>By popular demand, Madagascar&#8217;s FFT-based programs (such as <a href=\"\/RSF\/sffft1.html\">sffft1<\/a> and <a href=\"\/blog\/2012\/07\/02\/program-of-the-month-sffft3\/\">sffft3<\/a>) include now an optional support for FFTW. The presence of the FFTW single-precision library is detected during compilation. The following table shows some peformance measurements (CPU time in seconds for 1,000 complex-valued FFTs using <strong>sffft3<\/strong>): <\/p>\n<table  border=\"1\" cellpadding=\"0\" cellspacing=\"1\" class=\"table table-bordered table-striped\">\n<tr>\n<th bgcolor=\"#99CCCC\">data length<\/th>\n<th bgcolor=\"#99CCCC\">KISS FFT<\/th>\n<th bgcolor=\"#99CCCC\">FFTW<\/th>\n<\/tr>\n<tr>\n<td align=\"right\"> 4,096 <\/td>\n<td align=\"center\"> 0.11<\/td>\n<td align=\"center\"> 0.08<\/td>\n<\/tr>\n<tr>\n<td align=\"right\"> 8,192 <\/td>\n<td align=\"center\"> 0.27<\/td>\n<td align=\"center\"> 0.18<\/td>\n<\/tr>\n<tr>\n<td align=\"right\"> 16,384 <\/td>\n<td align=\"center\"> 0.50<\/td>\n<td align=\"center\"> 0.32<\/td>\n<\/tr>\n<tr>\n<td align=\"right\"> 32,768 <\/td>\n<td align=\"center\"> 1.21<\/td>\n<td align=\"center\"> 0.80<\/td>\n<\/tr>\n<tr>\n<td align=\"right\"> 65,536 <\/td>\n<td align=\"center\"> 2.61<\/td>\n<td align=\"center\"> 1.78<\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":"<p>FFTW (the Fastest Fourier Transform in the West) is a famous library implementing an FFT algorithm. It was developed at MIT by Matteo Frigo and Steven G. Johnson and is distributed under a GPL license. By popular demand, Madagascar&#8217;s FFT-based programs (such as sffft1 and sffft3) include now an optional support for FFTW. The presence [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":4,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":""},"categories":[6],"tags":[],"class_list":["post-298","post","type-post","status-publish","format-standard","hentry","category-systems"],"_links":{"self":[{"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/posts\/298","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/comments?post=298"}],"version-history":[{"count":3,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/posts\/298\/revisions"}],"predecessor-version":[{"id":20035,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/posts\/298\/revisions\/20035"}],"wp:attachment":[{"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/media?parent=298"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/categories?post=298"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/tags?post=298"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}