The General tab

Figure 288: Run Parameters - General tab

With the General tab selected you have access to values and options which apply to both the standard integrator and fixed step integrator, as in the example shown in the figure above. The Value column is editable. If a value is displayed in bold type, it is a non-default value. A value displayed in red is invalid, and a value displayed in orange is out of the advised range. The different numbered elements are described below.

Simulation settings

• Start time and Final time

Start time: Simulation start time. If the value is displayed in red, it is an invalid value. The start time must be smaller than the final time.

Final time: Simulation end time. If the value is displayed in red, it is an invalid value. The final time must be greater than the start time.

• Print interval, Number of points and Sampling frequency

Print interval: Interval at which results are saved in the results file. If the value is displayed in orange, the value is too small. You must increase the value for a smaller result file. If the value is displayed in red, the value is invalid. The print interval must be positive. During the run, data is added to the results file. The print interval specifies how often this is done. The smaller the print interval, the larger the .results file is. The print interval may influence the initial step size used by the Simcenter Amesim variable-step integrator. Usually this does not affect the simulation results. However, if needed, the initial value of the step size can be defined using the SIMP00 submodel of the Simulation library.

Number of points: This is the number of points saved for each result. This does not include any discontinuity printouts. If the value is displayed in red, the value is invalid. The number of points must be greater than 1. If the value is displayed in orange, the value is too large. You must decrease the value for a smaller result file. To change a value double-click on it and type the new value in the editing box.

Sampling frequency: The result Sampling frequency is the inverse of the Print interval. Sampling results at 100 Hz makes it easy to see oscillations at 10 Hz. Sampling frequency = 1 / Print interval. If the value is displayed in red, the value is invalid. The sampling frequency must be positive. If the value is displayed in orange, the value is too large. You must decrease the value for a smaller result file.

• Continuation run With a Continuation run, the run will continue from where it was last stopped (current start time is ignored). User-defined initial conditions are ignored and final values from the previous run are used instead. Results are concatenated with previous results. This option is disabled by default. Sometimes you do a simulation run and you subsequently wish you had set a greater final time. You can reset it and execute the whole run again but this is not attractive if the run was long. The alternative is:

increase the final time, and,

enable the Continuation run checkbox.

The .results file will be read and state variable values will be used as starting values for next run. In this run the Start time will be the final time in the .results file and the Final time will be the new value defined in the Value column.

• Use old final values With Use old final values, the run will start from the previous system state. User-defined initial conditions are ignored and final values from the previous run are used instead.

Simulation type

• Single run Executing a run will start a single simulation. Single run examples are presented in the Getting started section of the Tutorial manual.

• Batch run Executing a run will start a batch of simulations.

• Design matrix Select the batch configurations you want to run. If Batch is selected, the Design matrix button is enabled. Click this button if you want to define which runs to keep or remove. Figure 289: Design matrix dialog box

Note You can configure the application so that the Design matrix dialog box opens automatically prior to any simulation run when the Start Simulation button is clicked and Run type is set to Batch in the Run Parameters dialog box. See the Preferences page for more information.

Parallel processing

• Parallel processing preferences This option opens the Simcenter Amesim Preferences > Parallel processing tab, where you can configure your parallel processing options. The maximum number of simulation runs is 8. The maximum number of parallel runs per job is 2. The first parameter (Max. number of simultaneous runs) indicates the maximum number of runs to be processed simultaneously on a machine for a given Simcenter Amesim session. This limit will take into account any runs launched from a single Simcenter Amesim batch run or single run. If Simcenter Amesim is used on a multi-core machine (for example n cores/CPUs), we recommend you set this limit to n. If you prefer to keep one CPU for other tasks, you should specify n-1. Figure 290: Setting up local runs

The second parameter indicates the number of runs to be performed in parallel for a batch run or a design exploration study. In the example above, the maximum number of parallel runs per job is set to 2. This means that each batch run or design exploration study launched from Simcenter Amesim will be performed with 2 runs in parallel. This parameter should be specified according to the power of the machine on which Simcenter Amesim is used. The default value is 2, as many computers today are dual-core machines. If you are using a quad-core machine, we recommend setting this value to 4 (and even to 8 if hyperthreading is available). Note The second parameter will always be limited by the first (you cannot launch a greater number of parallel runs in a batch than the maximum number allowed for a given Simcenter Amesim session). Both configurations will of course have to take into account the number of licenses available for the system. If you specify more runs than licenses available, only the number of runs allowed by the license system will be performed, the remaining runs will be queued until the required license token is released.

Please refer to the Parallel Processing manual for a complete description of this facility.

Result file(s)

Estimation of the result file size. This does not include any discontinuity printouts that may occur. Hence the actual result file size could be larger.

Integrator type

• Standard integrator The Simcenter Amesim variable step integrator is used to solve the equations of the model.

• Fixed step integrator A fixed step integrator is used to solve the equations of the model. If you have any sort of implicit variables in your system, you will not be able to select the Fixed step integrator.

Information

Information and Warning

The first section is always visible and gives current print interval, number of points, sampling frequency and the easily observable frequency.

The second section is displayed only when the fixed-step solver is selected and it says: "Fixed step integrator is selected. The quality of the results will depend on the fixed step value".

The third section gives the following type of warning: "The size of the results file is over 2GB. Results after approximately xxxx s won't be available".

Miscellaneous

• Monitor Time Uncheck this option if you do not want the time to appear when the run is launched from the command line. Note This option need to be activated to enable discontinuities to be listed in the run details window.

• Statistics A brief summary of what happened in the run is displayed at the end of the simulation. Figure 291: Summary of the run characteristics

• Generate CSV All the variables in the Watch window will be exported to a file named ./${system_name_.csv} at the end of the simulation run. See Exporting watch variables for more information.