{"id":9728,"date":"2019-05-22T23:01:33","date_gmt":"2019-05-23T09:01:33","guid":{"rendered":"http:\/\/www.eaobservatory.org\/jcmt\/?p=9728"},"modified":"2020-12-29T11:00:36","modified_gmt":"2020-12-29T21:00:36","slug":"fix-for-skyloop-convergence-problem","status":"publish","type":"post","link":"https:\/\/www.eaobservatory.org\/jcmt\/2019\/05\/fix-for-skyloop-convergence-problem\/","title":{"rendered":"Fix for skyloop convergence problem"},"content":{"rendered":"<p>A bug in the <span style=\"font-family: 'courier new', courier, monospace\">smurf:skyloop <span style=\"font-family: georgia, palatino, serif\">command has recently been found and fixed. This bug could cause negative or zero values to be included in the extinction\u00a0 (&#8220;EXT&#8221;) model. This in turn could cause effectively random behaviour in the other models, resulting in very poor convergence and some spurious values being introduced into the final map (if convergence does eventually happen). This bug is triggered by one or more observations having some time slices for which no extinction values are available (indicated by the presence of the string <span style=\"font-family: 'courier new', courier, monospace\">&#8221; EXT:&#8221;<\/span> in the <span style=\"font-family: 'courier new', courier, monospace\">skyloop<\/span> log file). If such holes in the extinction data extend over only a few time slices, skyloop interpolates across them using the extinction values on either side of the hole. However,\u00a0 there was an error in this interpolation that led to the holes being filled with negative or zero values. This bug has now been fixed (as of 22nd May 2019).\u00a0 This fix affects both direct use of <span style=\"font-family: 'courier new', courier, monospace\">skyloop<\/span> and indirect use via the <span style=\"font-family: 'courier new', courier, monospace\">pol2map<\/span> command.<\/span><\/span><\/p>\n<p>David<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A bug in the smurf:skyloop command has recently been found and fixed. This bug could cause negative or zero values to be included in the extinction\u00a0 (&#8220;EXT&#8221;) model. This in turn could cause effectively random behaviour in the other models, resulting in very poor convergence and some spurious values being\u2026 <a class=\"continue-reading-link\" href=\"https:\/\/www.eaobservatory.org\/jcmt\/2019\/05\/fix-for-skyloop-convergence-problem\/\">Continue reading<\/a><\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[36],"tags":[37,46,47],"_links":{"self":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/posts\/9728"}],"collection":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/comments?post=9728"}],"version-history":[{"count":3,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/posts\/9728\/revisions"}],"predecessor-version":[{"id":9731,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/posts\/9728\/revisions\/9731"}],"wp:attachment":[{"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/media?parent=9728"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/categories?post=9728"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.eaobservatory.org\/jcmt\/wp-json\/wp\/v2\/tags?post=9728"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}