4.1 Debugging: Bookmarks, Delta Cycle and Virtual Grouping in Waveform Viewer Riviera PRO provides a fast-performance simulation engine with a comprehensive waveform viewer. During simulation, using the waveform viewer along with its tools can provide an overall more effective and better debugging experience. This video will cover how to use bookmarks, look at delta cycles, create virtual groups, and look at transactions on the waveform viewer.