{"action":"created","issue":{"url":"https://api.github.com/repos/RobotLocomotion/drake/issues/1534","labels_url":"https://api.github.com/repos/RobotLocomotion/drake/issues/1534/labels{/name}","comments_url":"https://api.github.com/repos/RobotLocomotion/drake/issues/1534/comments","events_url":"https://api.github.com/repos/RobotLocomotion/drake/issues/1534/events","html_url":"https://github.com/RobotLocomotion/drake/issues/1534","id":122583421,"number":1534,"title":"Concatenating two systems","user":{"login":"eric-wieser","id":425260,"avatar_url":"https://avatars.githubusercontent.com/u/425260?v=3","gravatar_id":"","url":"https://api.github.com/users/eric-wieser","html_url":"https://github.com/eric-wieser","followers_url":"https://api.github.com/users/eric-wieser/followers","following_url":"https://api.github.com/users/eric-wieser/following{/other_user}","gists_url":"https://api.github.com/users/eric-wieser/gists{/gist_id}","starred_url":"https://api.github.com/users/eric-wieser/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/eric-wieser/subscriptions","organizations_url":"https://api.github.com/users/eric-wieser/orgs","repos_url":"https://api.github.com/users/eric-wieser/repos","events_url":"https://api.github.com/users/eric-wieser/events{/privacy}","received_events_url":"https://api.github.com/users/eric-wieser/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-12-16T19:27:24Z","updated_at":"2015-12-17T01:40:01Z","closed_at":null,"body":"If I want the output of one system to go to the input of the next, ie `y = f(u), z = g(y)`, I can use `cascade` to get `z = h(u)`\r\n\r\nWhat function can I use to turn `y = f(u), z = g(v)` into a single plant `[y;z] = h([u;v])`, such that I can pass it into trajectory optimization?"},"comment":{"url":"https://api.github.com/repos/RobotLocomotion/drake/issues/comments/165310349","html_url":"https://github.com/RobotLocomotion/drake/issues/1534#issuecomment-165310349","issue_url":"https://api.github.com/repos/RobotLocomotion/drake/issues/1534","id":165310349,"user":{"login":"RussTedrake","id":6442292,"avatar_url":"https://avatars.githubusercontent.com/u/6442292?v=3","gravatar_id":"","url":"https://api.github.com/users/RussTedrake","html_url":"https://github.com/RussTedrake","followers_url":"https://api.github.com/users/RussTedrake/followers","following_url":"https://api.github.com/users/RussTedrake/following{/other_user}","gists_url":"https://api.github.com/users/RussTedrake/gists{/gist_id}","starred_url":"https://api.github.com/users/RussTedrake/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/RussTedrake/subscriptions","organizations_url":"https://api.github.com/users/RussTedrake/orgs","repos_url":"https://api.github.com/users/RussTedrake/repos","events_url":"https://api.github.com/users/RussTedrake/events{/privacy}","received_events_url":"https://api.github.com/users/RussTedrake/received_events","type":"User","site_admin":false},"created_at":"2015-12-17T01:40:01Z","updated_at":"2015-12-17T01:40:01Z","body":"That would be a “parallel combination”.  We don’t use it much, but hopefully it will work:  http://drake002.csail.mit.edu/drake/doxygen_matlab/class_dynamical_system.html#acb165e6d663ef0266acb61e50d30f6ee\n\n"}}