Time Variable

Context

The Time Variable is a parameter that represents time and can be used in formulas that describe probability distributions. This variable is activated from the Graph Panel background’s context menu. Its value is always observed; it is a positive integer that corresponds to the current time step of the Dynamic Bayesian Network (as shown in the time meter in Validation Mode).

This is not a standard Bayesian network variable. When it is activated, it can be used in the formula of any node. The corresponding probability tables do not reference it explicitly; only the probability values depend directly on its value. The Status Bar icon indicates that this variable is available:

During temporal inference, after each time increment, the probability distributions described by equations that use this parameter are updated. In Modeling Mode, its value is set to zero; the resulting probability tables are computed by replacing t with 0.

Using this parameter transforms the network into a dynamic Bayesian network.