Part 6 - Visualizing the Results With the IDE

6.1 Visualizing output scalars and vectors

The OMNeT++ IDE can help you to analyze your results. It supports filtering, processing and displaying vector and scalar data, and can display histograms, too. The following diagrams have been created with the Result Analysis tool of the IDE.

The results directory in the project folder contains .vec and .sca files, which are the files that store the results in vector and scalar form, respectively. Vectors record data values as a function of time, while scalars typically record aggregate values at the end of the simulation. To open the Result Analysis tool, double click on either the .vec or the .sca files in the OMNeT++ IDE. Both files will be loaded by the Result Analysis tool. You can find the Browse Data tab at the bottom of the Result Analysis tool panel. Here you can browse results by type by switching the various tabs at the top of the tool panel, ie. Scalars, Vectors, or Histograms. By default, all results of a result type are displayed. You can filter them by the module filter to view all or some of the individual modules, or the statistic name filter to display different types of statistics, ie. mean, max, min, standard deviation, etc. You can select some or all of the individual results by highlighting them. If you select multiple results, they will be plotted on one chart. Right click and select Plot to display the figures.

Tip

For further information about the charting and processing capabilities, please refer to the OMNeT++ Users Guide (you can find it in the doc directory of the OMNeT++ installation).

Our last model records the hopCount of a message each time the message reaches its destination. To plot these vectors for all nodes, select the 6 nodes in the browse data tab. Right click and select Plot.

We can change various options about how the data on the chart is displayed. Right click on the chart background, and select Properties. This opens the Edit LineChart window. In the Lines tab, set Line type to Dots, and Symbol Type to Dot.

To add a legend to the chart, select Display legend on the Legend tab.

The chart looks like the following:

If we apply a mean operation we can see how the hopCount in the different nodes converge to an average. Right-click the chart, and select Apply -> Mean. Again, right-click on the chart background, and select Properties. In the Lines tab, set Line type to Linear, and Symbol Type to None. The mean is displayed on the following chart. The lines are easier to see this way because they are thinner.

Scalar data can be plotted on bar charts. The next chart displays the mean and the maximum of the hopCount of the messages for each destination node, based on the scalar data recorded at the end of the simulation. In the Browse data tab, select Scalars. Now select hop count:max and hop count:mean for all 6 nodes.

To create a histogram that shows hopCount's distribution, select Histograms on the Browse data tab. Select all nodes, and right click Plot.