The Discontinuities pane

The Discontinuities pane exposes submodels that produce discontinuities during the simulation. It allows you to easily identify which submodels requested the solver to stop and start again and at which time. It also allows an easier detection of bad discontinuity handling in some submodels.

Note

Discontinuities are not themselves a problem. They are used to ensure model continuity for integration algorithms. The counterpart of these is that you need to restart the solver once a discontinuity has been processed. This restart can be time consuming in terms of CPU and can lead to a general slowdown of the simulation.

Identifying submodels generating discontinuities

The Discontinuities pane allows you to detect which submodel requested handling of a restart from the solver, giving the ability to identify the source of this request. The presented list of submodels also allows you to sort submodels by number of discontinuities they are generating throughout the entire simulation time range.

This list can be automatically updated during the integration. You can also manually select/deselect some submodels in this list, which will add or remove them from the graphical representation on the right. Of course only submodels having generated at least one discontinuity from the beginning of the simulation are present in the list.

The Pie chart view gives a global instantaneous view of submodels producing discontinuities in the system.

Figure 49: Pie chart view of share of discontinuities between most contributing submodels

Only submodels contributing to more than 1 % of the total number of discontinuities are enabled by default. The others are grouped in the "Others" share, which contains the contributions of all the deselected submodels.

If you require a more detailed analysis, switch to the Curves pane to get both the instantaneous and cumulative contributions of the submodels in terms of solver restart request. Note that the Curves pane plots are synchronized with the ones from the Run statistics and State contributions panes (the placement of the X-cursor coordinates bar on time range is preserved over the different features), which allows a local analysis of performances when considering a simulation slow down at a specific time.

Figure 50: Curve view of cumulative and instantaneous contributions of submodels in terms of discontinuities

The instantaneous contribution denotes the number of discontinuities generated between two updates (let’s say 1 thousand steps). The cumulative contribution denotes the number of discontinuities generated by one submodel since the beginning of the simulation (which is thus a growing number).

Double-clicking on a submodel allows you to locate it on the sketch, center the view on it, and display its label. Note that in the case of systems embedding cosimulation interfaces, the communication between Simcenter Amesim and the external solver might produce discontinuities such that a specific title cosimulation has been introduced to denote events due to the synchronization with external solvers. This item, not being specially linked to any submodel on the sketch, does not allow localization on it when you double-click on the list.

Figure 51: Discontinuities pane of system embedding a cosimulation interface block