Transitions
Each State Class in a Stratum can have any number of Transition pathways. Every Transition pathway is characterized according to the following fields:
Iteration (optional)
The Iteration for the pathway. If blank then the pathway applies to all iterations.
Timestep (optional)
The Timestep for the pathway. If blank then the pathway applies to all timesteps.
Primary Stratum (optional)
The Primary Stratum for the source State Class of the pathway.
Class
The source State Class of the pathway.
To Primary Stratum (optional)
The Primary Stratum for the destination State Class of the pathway. Default value (if left blank) is the same as Primary Stratum.
To Class (optional)
The destination State Class of the pathway.
Secondary Stratum (optional)
The Secondary Stratum for the State Class.
Tertiary Stratum (optional)
The Tertiary Stratum for the State Class.
Transition Type
The Transition Type associated with the pathway.
Probability
The probability that this pathway will occur for the specified timestep.
Proportion (optional)
This Proportion field is used to help represent multiple branching pathways associated with a single Transition type for a particular source State Class.
For example, suppose that there is a probability of 0.1 that a "Fire" Transition may occur for a particular source State Class, and that there are two possible pathways out of this class associated with this "Fire" Transition type, each occurring 50% of the time. Both pathways can be assigned the same value for the Prob field (i.e. 0.1), and then each pathway is assigned a value of 0.5 for the Propn field. When the model runs, the effective probability is calculated as Prob x Propn. Default value (if left blank) is 1.
Age Min (optional)
The minimum age for a simulation cell to be eligible for this pathway. The default value (if left blank) is the minimum age of the State Class to which the Transition applies.
Age Max (optional)
The maximum age for a simulation cell to be eligible for this pathway. The default value (if left blank) is the maximum age of the State Class to which the Transition applies.
Age Shift (optional)
The relative change in the age of the simulation cell after the Transition occurs. For example, if the age of the simulation cell is 50 prior to the transition, and the Age Shift is set to -20 for a pathway, then the post-Transition age of the simulation cell will be 50-20=30. Note that the age of the simulation cell after a Transition can never be outside the bounds of the ages for the destination State Class. Default value (if left blank) is 0.
Age Reset (optional)
If set to 'Yes' then the age of the simulation cell is reset to the minimum age of the destination State Class after a Transition occurs. For example if the minimum age of the destination State Class is 10, and the Age Reset is set to 'Yes', then the post-Transition age of the simulation cell will always be set to 10 (regardless of the source State Class age). If Age Reset is set to 'No' then the age will be set to the nearest value to the current age of the cell that still satisfies the age constraints of the destination state class. Note that this feature can be used in conjunction with the Age Shift field: so for example if the Age Shift is set +20 for the example above, then the post-Transition age of the simulation cell will be 10+20=30. Default value (if left blank) is 'Yes'.
TST Min (optional)
The minimum "time-since-transition" value for the simulation cell to be eligible for this pathway. Default value (if left blank) is 0.
TST Max (optional)
The maximum "time-since-transition" value for the simulation cell to be eligible for this pathway. Default value (if left blank) is 9999.
TST Shift (optional)
The relative change in the "time-since-transition" (TST) value of the simulation cell after the Transition occurs.
For example, if the TST of the simulation cell is 40 prior to the transition, and the TST Shift is set to -20 for a pathway, then the post-Transition TST of the simulation cell will be 40-20=20. Note that the TST of the simulation cell after a Transition can never be less than 0. Default value (if left blank) is -9999.
See Also
Use the Pathway Diagram to edit your Transitions more easily.