Converting between Within-Cycle Correction and Half-Cycle Correction

34.7 Converting between Within-Cycle Correction and Half-Cycle Correction

When you change between Traditional and Within-Cycle Correction (WCC) within Tree Preferences, TreeAge Pro will try to convert the current reward entries from one configuration to another. However, you will then need to review all state rewards to ensure the data is correct.

This section now considers both mechanisms. When building a model, the options available are to use the Traditional Markov method with or without Half-Cycle Correction or to use a Markov Model using Within-Cycle Correction.

You can find more details about setting up Half-Cycle Correction (HCC) or Within-Cycle Correction in the appropriate sections.

Conversion between Within-Cycle Correction and Half-Cycle Correction

Markov Models either use the Traditional or Within-Cycle Correction method. Once your model is built, it is possible to convert between the methods with a one-time conversion of your rewards.

Traditional to Within-Cycle Correction conversion:

Open the example model Markov 3 State - Traditional.trex. (When you are converting your own models, its good practice to save them under a different name first).
Open Tree Preferences and select the category Calculation > Markov/DES.
Observe the current model is set for Traditional Half-Cycle Correction.
Select Within-Cycle Correction and observe the dialogue warning about the conversion.
Select 'Confirm' and review and edit the rewards via the Markov View, as required.

The conversion from Traditional to Within-Cycle Correction will do the following operations on the rewards:

Incremental rewards from the Traditional model will be copied into the Cycle rewards of the WCC model.
Initial and Final rewards will not be converted into the WCC model. They are remembered should you convert back to a Traditional Markov model, but they are not used in the WCC conversion (see Warning below).

NOTE: Be careful when applying HCC using the steps above. Clicking the Half-cycle Correction button will delete any entries in the Initial and Final rewards and replace them with half the Incremental Reward. If you have any additional entries in those Initial and Final fields (particularly up-front costs in the initial reward), be sure to add those back into the model after applying HCC.

Within-Cycle Correction conversion to Traditional:

Open the Markov 3 State - WCC.trex model. (When you are converting your own models, its good practice to save them under a different name first).
Open Tree Preferences and select the category Calculation > Markov/DES.
Observe the current model is set for Within-Cycle Correction.
Select Traditional Half-Cycle Correction and observe the dialogue warning about the conversion.
Select 'Confirm' and review and edit the rewards via the Markov View, as required.

The conversion from Within-Cycle Correction to Traditional will do the following operations on the rewards:

Cycle rewards from the WCC model will be copied into the Init, Incr and Final rewards with Half-Cycle Correction applied in the Traditional model.
The Start-up and Event rewards for WCC Health States will not be converted into the Traditional model. They are remembered should you convert the model back to WCC, but they are not used.

Converting a model into a different format will only convert the Rewards once. Lets assume you convert from Traditional to WCC. With this conversion, the Incr and Final rewards are not used in the new WCC model. Then, if you converted the model back from WCC to Traditional, the model would remember the original Incr and Final rewards from the original Traditional model. The usual conversion algorithm would not work because the model would already have values assigned to Incr and Final from when the model was built.

The same is true of models which start as WCC, with rewards for Startup, Cycle and Event.