Slow / Failed simulation when using directional derivatives

[DeadParrot]

Directional derivative support is important in the FMUs used for QSS for accurate event indicator trajectories (needed for zero-crossing protocol robustness) and may be used for state variable second derivatives in future QSS versions. There are a few issues with the current OCT directional derivative support:

• PyFMI runs fail (but not QSS) for some models built with directional derivative support:

  • ASHRAE2006
  • Edit: TwoFloor_TwoZone fails with the OCT-r23206_JM-r14295 build if directional derivatives are enabled with "Evaluating the derivatives failed"

• PyFMI and QSS runs progress very slowly for some models built with directional derivative support:

  • Guideline36
  • Edit: With the OCT-r23206_JM-r14295 update this now fails with "Simulation failed: 'The right-hand side function had repeated recoverable errors. At time 39120.000000.'"
  • Guideline36Spring

• ACControl10 has an event indicator of time - nextSample that is not getting the time contribution back from the call for the directional derivatives, breaking the QSS simulations, but the TimeTest model with the same event indicator gets the correct directional derivative

[DeadParrot]

Versions

The issue was observed with these component versions (may occur with others):

Component	Version	Date
OCT	OCT-r23206_JM-r14295	2021/05
Buildings	9c37781	2021/05/04
QSS	e4a0f62	2021/06/08

Build

Build the FMU with bld from the OCT directory as described in the Status page.

Run

Run the models with PyFMI or QSS from a console configured as described in the Status page.

PyFMI: Use run under the model OCT directories to generate the CVode simulation.

QSS: Use run under the model QSS directory in a method subdirectory such as QSS2.

[DeadParrot]

The ACControl10 event indicator noted now gets the correct directional derivatives with the OCT-r28312_JM-r14295 update.

[DeadParrot]

With the OCT-r28312_JM-r14295 update the CVode run of the ASHRAE2006 model built with directional derivatives terminates with:

Warning: Possible chattering detected at t = 1.308000e+04 in state event(s): [57 59 61 63 65]
Simulation failed:  'The right-hand side function had repeated recoverable errors. At time 39240.000000.

[chria]

Two bullet split into:

https://github.com/NREL/SOEP-QSS-Test/issues/22 https://github.com/NREL/SOEP-QSS-Test/issues/21

rest is fixed.