{"id":1128,"date":"2012-08-01T20:53:04","date_gmt":"2012-08-02T01:53:04","guid":{"rendered":"https:\/\/blogs.mathworks.com\/seth\/?p=1128"},"modified":"2012-08-01T20:54:29","modified_gmt":"2012-08-02T01:54:29","slug":"upgrading-simulink-libraries-with-forwarding-tables-and-transformation-functions","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/simulink\/2012\/08\/01\/upgrading-simulink-libraries-with-forwarding-tables-and-transformation-functions\/","title":{"rendered":"Upgrading Simulink Libraries with Forwarding Tables and Transformation Functions"},"content":{"rendered":"

If you create and maintain Simulink libraries used in many models, or by many people, I think you will like this R2012a new feature: Interactive Library Forwarding Tables for Updating Links<\/a>.
\r\n
Note:<\/em> Library Forwarding Tables have been around for a long time, but they used to be available through the command line only. This new feature in R2012a adds an enhanced interface to this old capability: set_param('Lib1', 'ForwardingTable', {{'Lib1\/A', 'Lib2\/A'} {'Lib1\/B', 'Lib1\/C'}});<\/tt>.<\/p>\r\n\r\n

The Challenge<\/strong><\/p>\r\n\r\n

Let's say I create a library block with 2 mask parameters, a<\/strong> and b<\/strong><\/p>\r\n\r\n

\"Initial<\/p>\r\n\r\n

A few weeks or months later, I decide to modify the library and combine a<\/strong> and b<\/strong> into only one, equivalent parameter c<\/strong>:<\/p>\r\n\r\n

\"Modified<\/p>\r\n\r\n

The next time a user will open his model using this library block, he will receive a warning like the following:<\/p>\r\n\r\n

\"Warning:<\/p>\r\n\r\n

and the value for the new parameter c<\/strong> will be the default coming from the library. a<\/strong> and b<\/strong> will be lost.<\/p>\r\n\r\n

The Solution<\/strong><\/p>\r\n\r\n

To avoid loosing values for a<\/strong> and b<\/strong> stored in the model, you can write a transformation function.<\/p>\r\n\r\n

First, go to the File<\/strong> menu of the library. In the Library Properties dialog, go to the Forwarding Table tab and add an entry for your block:<\/p>\r\n\r\n

\"Library<\/p>\r\n\r\n

Create a transformation function to process the value of a<\/strong> and b<\/strong> stored in the model and create the new value for c<\/strong>.<\/p>\r\n\r\n

\"Example<\/p>\r\n\r\n

I recommend going through the documentation section Making Backward-Compatible Changes to Libraries<\/a> for more details and examples of the syntax to use in this function.<\/p>\r\n\r\n

With this transformation applied, your users will be happy to see that the values they had previously set for a<\/strong> and b<\/strong> are kept:<\/p>\r\n\r\n

\"Before<\/p>\r\n\r\n

Now it's your turn<\/strong><\/p>\r\n\r\n

Of course, the example above is very simple, to highlight the concept. Give a look at the documentation section Making Backward-Compatible Changes to Libraries<\/a> and let us know if this functionality is useful for you by leaving a comment here<\/a><\/p>\r\n","protected":false},"excerpt":{"rendered":"

If you create and maintain Simulink libraries used in many models, or by many people, I think you will like this R2012a new feature: Interactive Library Forwarding Tables for Updating Links.\r\nNote:... read more >><\/a><\/p>","protected":false},"author":41,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[8,69,16],"tags":[281,45,25],"_links":{"self":[{"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/posts\/1128"}],"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\/41"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/comments?post=1128"}],"version-history":[{"count":20,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/posts\/1128\/revisions"}],"predecessor-version":[{"id":1180,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/posts\/1128\/revisions\/1180"}],"wp:attachment":[{"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/media?parent=1128"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/categories?post=1128"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/simulink\/wp-json\/wp\/v2\/tags?post=1128"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}