Member predicate MetricNamespace::getDistanceFromMain

Gets the distance from main sequence of this namespace. This measure intends to capture the tradeoff between abstractness and instability: the ideal situation occurs when the sum of abstractness and instability is one. That is, a namespace is completely abstract and stable (abstractness=1 and instability=0) or it is concrete and instable (abstractness=0 and instability=1). We thus measure the distance from that ideal situation.