{"action":"opened","issue":{"url":"https://api.github.com/repos/tbeu/fmi-standard/issues/350","repository_url":"https://api.github.com/repos/tbeu/fmi-standard","labels_url":"https://api.github.com/repos/tbeu/fmi-standard/issues/350/labels{/name}","comments_url":"https://api.github.com/repos/tbeu/fmi-standard/issues/350/comments","events_url":"https://api.github.com/repos/tbeu/fmi-standard/issues/350/events","html_url":"https://github.com/tbeu/fmi-standard/issues/350","id":370360575,"node_id":"MDU6SXNzdWUzNzAzNjA1NzU=","number":350,"title":"Provide an interface / technique for a co-simulation FMU to express a preferred or essential communication step size.","user":{"login":"modelica-trac-importer","id":22202507,"node_id":"MDQ6VXNlcjIyMjAyNTA3","avatar_url":"https://avatars1.githubusercontent.com/u/22202507?v=4","gravatar_id":"","url":"https://api.github.com/users/modelica-trac-importer","html_url":"https://github.com/modelica-trac-importer","followers_url":"https://api.github.com/users/modelica-trac-importer/followers","following_url":"https://api.github.com/users/modelica-trac-importer/following{/other_user}","gists_url":"https://api.github.com/users/modelica-trac-importer/gists{/gist_id}","starred_url":"https://api.github.com/users/modelica-trac-importer/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/modelica-trac-importer/subscriptions","organizations_url":"https://api.github.com/users/modelica-trac-importer/orgs","repos_url":"https://api.github.com/users/modelica-trac-importer/repos","events_url":"https://api.github.com/users/modelica-trac-importer/events{/privacy}","received_events_url":"https://api.github.com/users/modelica-trac-importer/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":{"login":"tbeu","id":5444067,"node_id":"MDQ6VXNlcjU0NDQwNjc=","avatar_url":"https://avatars0.githubusercontent.com/u/5444067?v=4","gravatar_id":"","url":"https://api.github.com/users/tbeu","html_url":"https://github.com/tbeu","followers_url":"https://api.github.com/users/tbeu/followers","following_url":"https://api.github.com/users/tbeu/following{/other_user}","gists_url":"https://api.github.com/users/tbeu/gists{/gist_id}","starred_url":"https://api.github.com/users/tbeu/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/tbeu/subscriptions","organizations_url":"https://api.github.com/users/tbeu/orgs","repos_url":"https://api.github.com/users/tbeu/repos","events_url":"https://api.github.com/users/tbeu/events{/privacy}","received_events_url":"https://api.github.com/users/tbeu/received_events","type":"User","site_admin":false},"assignees":[{"login":"tbeu","id":5444067,"node_id":"MDQ6VXNlcjU0NDQwNjc=","avatar_url":"https://avatars0.githubusercontent.com/u/5444067?v=4","gravatar_id":"","url":"https://api.github.com/users/tbeu","html_url":"https://github.com/tbeu","followers_url":"https://api.github.com/users/tbeu/followers","following_url":"https://api.github.com/users/tbeu/following{/other_user}","gists_url":"https://api.github.com/users/tbeu/gists{/gist_id}","starred_url":"https://api.github.com/users/tbeu/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/tbeu/subscriptions","organizations_url":"https://api.github.com/users/tbeu/orgs","repos_url":"https://api.github.com/users/tbeu/repos","events_url":"https://api.github.com/users/tbeu/events{/privacy}","received_events_url":"https://api.github.com/users/tbeu/received_events","type":"User","site_admin":false}],"milestone":null,"comments":0,"created_at":"2018-10-15T21:58:55Z","updated_at":"2018-10-15T21:58:55Z","closed_at":null,"author_association":"COLLABORATOR","body":"**Reported by haanjj on 24 Sep 2015 17:02 UTC**\n### Motivation\nCo-Simulation master environments may involve time integration of\n1)        non-FMU participants that cannot repeat a step, for-example an FEA or CFD code, or\n2)        FMU participants that cannot repeat a step, for example if canGetAndSetFMUstate is not set/indicated in the model\n\n\nIn these cases the co-simulation master is incapable of employing adaptive error or stability control strategies that exploit abilities of participants to repeat a time step. Instead the co-simulation master is free to adapt time steps only in a go-forward sense.  Performance and stability of FMUs in these environments can benefit greatly from FMUs that provide the co-simulation master with a preferred or essential communication step size.\n\n\n\n### Preferred communication step size categories\n1)        Essential\n\n a. For stability / accuracy of the FMU, e.g. a co-simulation FMU knowing its stable time increment in cases where this is solution/state dependent.\n a. For accuracy of the system solution, e.g. controller sampling period.\n\n2)        Preferred\n\n a. In support of output at interesting times.\n\n### Current strategy\n(untested) Ideas for strategies available today, with FMI 2.0, include\n1)        Having the co-simulation master derive a time step from characteristics of the FMU (e.g. a Courant number), which might be achievable in ME/CS combined format FMUs\n2)        Having the co-simulation master perform a trial DoStep of the FMU as a test of whether and when a step event occurs.\n\n----\n\nMigrated-From: https://trac.fmi-standard.org/ticket/350"}}
{"actor":{"display_login":"modelica-trac-importer"}}