{"id":92,"date":"2010-04-29T14:22:58","date_gmt":"2010-04-29T14:22:58","guid":{"rendered":"https:\/\/blogs.mathworks.com\/seth\/2010\/04\/29\/causes-of-algebraic-loops\/"},"modified":"2020-12-08T13:00:58","modified_gmt":"2020-12-08T18:00:58","slug":"causes-of-algebraic-loops","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/simulink\/2010\/04\/29\/causes-of-algebraic-loops\/","title":{"rendered":"Causes of Algebraic Loops"},"content":{"rendered":"<p>A lot of people ask the question, \"Why does my model have an <a href=\"https:\/\/www.mathworks.com\/help\/releases\/R2010a\/toolbox\/simulink\/ug\/f7-8243.html#f7-19688\" >algebraic loop?<\/a>\"  Of course, every model is different, but here are some general truths about algebraic loops:<\/p>\r\n<ol>\r\n\t<li>Real physical systems don't have algebraic loops.<\/li>\r\n\t<li>If you model a physical system and get an algebraic loop, there is probably something missing in the model.<\/li>\r\n\t<li>Modeling short cuts simplify a simulation and make it more efficient, but can introduce algebraic loops.<\/li>\r\n\t<li>Sensors and actuators are commonly ignored, especially for low fidelity models. These are ideal places to introduce delay into your system and break the loop.<\/li>\r\n<\/ol>\r\n\r\n<p><img decoding=\"async\" src=\"https:\/\/blogs.mathworks.com\/images\/seth\/2010Q2\/missingSensors.png\" alt=\"Simulink models with missing sensors might encounter an algebraic loop if there is direct feed-through in the plant model.\" \/><\/p>\r\n\r\n<p><strong>Sensor Contest<\/strong><\/p>\r\n\r\n<p>Speaking of sensors, the 2010 Spring MATLAB programming contest started yesterday and is titled <strong><a href=\"https:\/\/www.mathworks.com\/matlabcentral\/contest\/contests\/2\">Sensor<\/a><\/strong>!<\/p> \r\n\r\n<p>The topic of this contest is compression sensing technology for digital images. You have until Wednesday, May 5th, to look at the <a href=\"https:\/\/www.mathworks.com\/matlabcentral\/contest\/contests\/2\/rules\">rules<\/a> and create your submission.<\/p> \r\n\r\n<p>You would like to be informed in advance of future programming contests? Visit the <a href=\"\">MATLAB Programming Contest Blog<\/a> to get updates automatically.<\/p>\r\n\r\n<p><strong>Good luck!<\/strong><\/p>\r\n\r\n<p>Good luck fixing your algebraic loops, and entering the Sensor contest!  Questions about algebraic loops?  Leave a <a href=\"https:\/\/blogs.mathworks.com\/seth\/?p=92&#comment\">comment here<\/a> and I'll try to answer.<\/p> ","protected":false},"excerpt":{"rendered":"<p>A lot of people ask the question, \"Why does my model have an algebraic loop?\"  Of course, every model is different, but here are some general truths about algebraic loops:\r\n\r\n\tReal physical systems... <a class=\"read-more\" href=\"https:\/\/blogs.mathworks.com\/simulink\/2010\/04\/29\/causes-of-algebraic-loops\/\">read more >><\/a><\/p>","protected":false},"author":40,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[71,30,39,33],"tags":[134,44,133,441],"_links":{"self":[{"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/posts\/92"}],"collection":[{"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/users\/40"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/comments?post=92"}],"version-history":[{"count":1,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/posts\/92\/revisions"}],"predecessor-version":[{"id":9942,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/posts\/92\/revisions\/9942"}],"wp:attachment":[{"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/media?parent=92"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/categories?post=92"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/tags?post=92"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}