Relative Density

This pattern describes anomalies in semantically related pairs of trace messages, for example, “data arrival” and “data display”. Their statement densities (Volume 4, page 335) can be put in a ratio (also called specific gravity⁵²) and compared between working and non-working scenarios. Because the total numbers of trace messages cancel each other we have just the mutual ratio of two message types. In our hypothetical “data” example the increased ratio of “data arrival” to “data display” messages accounts for reported visual data loss and sluggish GUI.

⁵² http://en.wikipedia.org/wiki/Relative_density