Result Comparison

It is possible to compare results that are computed on similar networks, but with different parameters. The comparison basically subtracts the results from one another. The comparison becomes a new result layer available for plot­ting on a result document (e.g. a result map, time series plot, table, profile plot, or bar chart).

The result comparison option supports the following result file types for com­parison: .res1d, .dfsu, .dfs2, .res, .resx, .out. Other file types cannot be com­pared.

Figure 20.98    Loading result files for comparison of results

To compare results:

·         Run two different instances of a simulation (e.g. network simulation) with different input parameters but on a similar network setup or on a 2D domain with unchanged grid / mesh.

·         If not automatically loaded, load the simulation results to compare on the Results manager. (See Chapter 20.3 - “Loading Results” on page 382)

·         Select one of the result file layers (i.e. File A) on the Results manager, and click on the ‘Compare...’ button at the top of the panel (Figure 20.98). This will launch a dialog listing other loaded result file lay­ers available for comparison with the currently-selected layer.

·         Alternatively, launch a file comparison via the results manager local con­text menu by right-clicking on a result file layer (Figure 20.99).

Figure 20.99    Compare results via the local context menu

·         Select the second (compatible) result file (i.e. File B) for the comparison and click on the ‘Compare’ button. The comparison takes values from the first result file and subtracts corresponding values from the second result file (i.e. File A minus File B).

·         A new result layer based on the comparison (i.e. differences) is created and added to the Results manager.

·         Result documents may be generated based on the various result items of the resulting comparison layer.

·         Create a result document (i.e. map plot, time series plot, etc.) via the file manager local context menu. (See Chapter 20.6 - “Creating Result Doc­uments” on page 389)

Differences in result items

Result items not common in the files being compared will not be available in the comparison result.

Differences in Time Steps and Period

Comparison is done based mainly on the order of time series values. A mis­match in the number of time steps results in time series containing the smaller number of rows. With .res1d results, mismatch in time series periods and time step widths will return a warning about the mismatch; continuing with the comparison should be reconsidered.

For .res, .resx, .dfs2 and .dfsu files, the comparison supports different simula­tion periods but doesn't support different time step intervals.

For .out files, the comparison requires that the two files have the same dura­tion and same reporting frequency.

Differences in Network Geometry

If the two result files have geometry differences (e.g. link deleted), the result comparison skips non-existing items. Thus it is still possible to compare sce­narios where e.g. network as been changed or extended.

Comparison Log File

The Comparison tool creates a log file in the project directory. The file is named similarly as the resulting comparison file but with a *.LOG extension. It contains information on the files being compared.