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2017-03-12 17:38:52 -0500 commented answer Reducing individual GenOpt simulation run times

Thank you for your thoughts Dr. Wetter. Using the parametric method described, all but 2 of the variables were removed, and each limited to 6 values. With UnitsOfExecution=8, 36 runs finished in 5.38 minutes (~75 sec/sim), while the same file with UnitsOfExecution=16 finished in 3.08 minutes (~83.5 sec/sim) (runtimes determined from GenOpt.log files).

These scenarios finish in under half the time simulations take running through an GPSPSOCCHJ algorithm iteration but still much longer than a normal E+ run. Would reducing the number of output variables help speed along the algorithm?

2017-03-02 19:05:49 -0500 asked a question Reducing individual GenOpt simulation run times

I have a question regarding how to decrease individual GenOpt (v3.1.0) (with EnergyPlus v8.6) run times.

An individual E+ pilot study model I am experimenting with can run directly from E+ in <20 seconds. In contrast, the same model while running using the GPSPSOCCHJ algorithm with GenOpt, individual run times tend to vary between 2.5 and 3 minutes.

The E+ idf file has been cleaned of all unused information (e.g. materials, constructions, schedules etc.) and is is 485KB in size. The base run time is between 11 and 16 seconds. The .idf is of a simple three zone test model with separate HVAC systems for each zone and three AirflowNetwork:MultiZone objects.

GenOpt's command file "UnitsOfExecution" setting has been tested with values = 2, 4, 6, 8, and 10 with no notable difference between individual simulation completion times.

It is reasonable to expect slightly longer run times due to GenOpt's read/write process and run the optimization maths, but 2+ minutes per simulation is quite a bit more than I would expect. Are there settings that can be modified in GenOpt to reduce this significant run time? Or could this be an odd E+ issue?

The simulations are running on a i7-5960X CPU (8-core, 16 threads, 3.4GHz ) equipped PC with Windows 7.

2016-01-14 07:13:41 -0500 received badge  Student (source)
2016-01-14 02:31:12 -0500 asked a question E+ Fatal error: Convergence error in SolveForWindowTemperatures

Having adjusted the Relative Airflow and Absolute Airflow convergence tolerances, as well as the Maximum Number of Iterations under AirflowNetwork:SimulationControl, which solved an earlier fatal error (Error: Too many iterations in Airflow Network simulation), I have encountered the fatal error below and have run out of ideas for resolving it. A google search turned up a similar problem with E+ v7 over on the Design Builder Forum but without a solution.

The Airflow Network I am attempting to simulate includes several large window openings which I understand can cause errors due to the high airflow transfer between zones. Reducing the aperture sizes is an obvious solution, however, high airflow/transfer rates is a desired quality of this test simulation so I would prefer to retain the large window openings.

(Using e+ v8.3.0 x64) Thank you in advance

From the *.err file:

** Severe  ** Convergence error in SolveForWindowTemperatures for window ZONE_1_WINDOW_005MM
**   ~~~   ** During Warmup, Environment=RUN PERIOD 1, at Simulation time=09/29 08:30 - 08:32
**   ~~~   ** Glazing face index = 1 ; new temperature =NANC  ; previous temperature = 9.4479C    
**   ~~~   ** Glazing face index = 2 ; new temperature =NANC  ; previous temperature = 13.9687C  
**  Fatal  ** Program halted because of convergence error in SolveForWindowTemperatures for window ZONE_1_WINDOW_005MM
...Summary of Errors that led to program termination:
..... Reference severe error count=1
..... Last severe error=Convergence error in SolveForWindowTemperatures for window ZONE 1 WINDOW 005MM