Improving performance of transient simulations (recommended reporting calculation options)

Product(s): HAMMER
Version(s): V8i, CONNECT Edition
Area: Calculations

Problem

What do the HAMMER Calculation Option Reporting fields control?

What settings should be used in the Calculation Options Reporting fields to optimize performance without compromising results? (and help prevent the reporting increment from being artificially increased as explained in this article)

Solution

Here are the descriptions of the properties in the reporting section of the transient calculation options.

Note that if your model is large, it may be best to skeletonize (simply) first. See: Preparing an existing model for a transient analysis in HAMMER

Generate Extended Output Log?

When the value is true, the output log includes additional information for every node, such as the flow, head, and vapor/air volumes at the first, second and last time steps.

To open the output log, go to the Report tab and select Analysis Output Log.

This setting will not make a significant impact on the time it takes to compute.

 
 

Show Pocket Opening/Closing?

Toggles whether the list of vapor pockets open and close times will be appended to the output text file.

To open the output log, go to the Report tab and select Analysis Output Log.

For Example:

The cavity at node "Air Valve" opens in 3.31 seconds.

The cavity at node "Air Valve" closes in 12.90 seconds.

This setting will not make a significant impact on the time it take to compute.

 

Generate Detailed Reports?

Toggles the generation of ASCII output text files on or off. These can become voluminous for simulations with many time steps and they are not required for the operation of the FlexTables or graphics. Some users prefer to set this setting to False. When this is set to true the generated report can be viewed by selecting the Report tab clicking Analysis Detailed Report.

 

Report Point History Type

Select All to generate point histories for all points in the text reports, or Only if On Path to generate report Histories only for those points that lie on a path.

Computing time will be lower when Only if on Path is selected.

 

Report Points

Specify whether to report results on All, Selected, or No points.

This controls the points that are computed and available to have their Time History plotted in the Transient Results Viewer.

Compute time will increase with the amount of points being reported. For optimal performance, it is recommended to set this to Selected. Then only include points you want to see the time history for.

Note that the list of report points in the dropdown in the Time History tab of the Transient Results Viewer cannot currently be sorted. The related Enhancement request is 903576. Using the Report Points option to filter down to only the notable locations will help establish a more manageable list.

 

Report Points Collection (available when Report Points is set to "Selected Points")

Clicking the ellipsis button in this field opens the Report Points Collection dialog, allowing you to choose the report points from the list of available points, or select them in the drawing.


 
See: How do you select only certain report points in the transient calculation options?

 

Report Times

Choose whether to report Periodically, At Specific Times, At No Times, or At All Times.

It is recommended to set this to "At All Times" to prevent the behavior in this article.

See Also

"The period between path histories has been increased by a factor of X to limit the number of path records to Y. "

How do you select only certain report points in the transient calculation options?

Transient maximum result is different from the highest value seen in a time history graph

Preparing an existing model for a transient analysis in HAMMER

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