Viewing Dependency Graphs to Understand Calculations

This article explains what a dependency graph is, how to view it, how to navigate using the dependency graph, and how to use it to identify bottlenecks in your code.

The dependency graph and how to view it

Outputs in Displayr can be either fixed - such as images and text. Or, they can be dependent on data, such as visualizations, calculations, and tables. When the output is dependent on data, you can right-click on the edge of the output and choose Dependency Graph from the context menu, Displayr shows you the dependency graph used to calculate the output and any downstream outputs.

The screenshot below shows a page in the Grocery Store NPS dashboard. The NPS promoter score (NPS) breakdown clustered pie chart is selected, and the dependency graph is shown at the bottom.

The dependency graph above shows that:

• The selected chart is named chart.2.
• chart.2 is calculated from a table called table.Q12r3_3_2.Bakery.by.Bakery.
• table.Q12r3_3_2.Bakery.by.Bakery is calculated from two variables: Q12r2_3_2: Bakery and Bakery.
• The two variables are from the data file Shopping.sav.

Using the dependency graph to navigate

You can navigate by clicking on nodes in the dependency graph. For example, the screenshot below shows the dependency graph from above, after table.Q12r3_3_2.Bakery.by.Bakery has been clicked on. 

The dependency graph shows you which objects in a document depend on which other objects. When you click on the objects, you can then inspect their properties in the object inspector to work out how the actual calculation is performed. For example, the example below shows that the word cloud depends on the variables Reasons for being a detractor: Bakery and Detractors: Bakery, and we can see in the object inspector that Detractors: Bakery is used to filter Reasons for being a detractor: Bakery. 

When you are finished using the dependency graph, you can click on the X in the right corner of the panel to close it. If you are looking at a dependency graph for a variable or output and there isn't anything to the right of it when you right click > Dependency Graph, then the item is not being used by any other items in the document. This is a useful way of seeing if a variable can be deleted or not.

Next

To examine any code within a calculation, variable, or data set, see How to Troubleshoot R Code in Displayr.

For more information on optimizing the performance of a document, see Optimize the Dependency Graph and How to Troubleshoot Speed and Performance Issues.