The extent to which one Variable depends on another Variable. Dependence affects the Likelihood of two or more thresholds being exceeded simultaneously. When it is not known whether dependence exists between two Variables or Parameters, guidance on the importance of any assumption can be provided by assessing the fully dependent and independent cases (see also Correlation).
(n.) The relationship of a calculation B to a calculation A if changes to A, or to the ordering of A and B, could affect B. If A and B are calculations in a program, for example, then B is dependent on A if B uses values calculated by A. There are four types of dependence: true dependence, where B uses values calculated by A; antidependence, where A uses values overwritten by B; output dependence, where A and B both write to the same variables; control dependence, where B's execution is controlled by values set in A. Dependence is also used in message routing to mean that some activity X cannot proceed until another activity Y has completed. For example, if X and Y are messages attempting to pass through a region with limited buffer space, and Y currently holds some or all of the buffer, X may depend on Y releasing some buffer space before proceeding.