Co-Simulation Orchestration Engine Sample Clauses

Co-Simulation Orchestration Engine. ‌ The Co-Simulation Orchestration Engine (XXX) is the core engine that is used for connecting different FMUs together in co-simulations in the INTO- CPS project. The sources for this development are stored in a private Git repository at xxxxx://xxxxxx.xxx/twt-gmbh. The executable derived from these sources is made freely available to all partners of the consortium (as well as external parties) and released at regular intervals. The XXX is built as a service and serves its clients using JSON over the HTTP protocol (see Appendix A), allowing clients to perform co-simulations based on a co-simulation configuration that is composed of a number of FMUs, their connections, parameters and the desired step-size algorithm. The XXX supports two types of step-size algorithms: Fixed step size algorithm: This algorithm performs fixed size steps with a predefined step size. However, the XXX uses this algorithm in com- bination with an error recovery feature that, under some constraints, can progress a discarded fixed step by a smaller step. This enables an otherwise fatal error to be recovered so the fixed step size algorithm can continue to drive the simulation after the discarded step is recov- ered. The recovery depends on the ability of all FMUs to roll-back and provide status information about the last successfully simulation time. If this is provided then XXX will roll-back all FMUs and calculate a smaller step size based on the current time and the minimum of the last successful time the FMUs reported and do a step with that size before resuming the use of the fixed step size algorithm. Variable step size algorithm: This algorithm performs variable steps. The algorithm is similar to Algorithm 2, and Algorithm 3 from [BBG+13a]. However our implementation of Algorithm 3 does not yet support step- ping the FMUs that supports roll-back but not getMaxStepsize first. The XXX implementation automatically detects if the INTO- CPS specific FMI extension to obtain the maximum step size for each FMU is available, and based on this selects the appropriate algorithm. When using the variable variable step size algorithm then XXX uses constraints on the connections to make sure that a given step does not result in instability [?] which is detected by a violation of one of the constraints. See Appendix B for in-depth details on how the variable step size calculation is performed.