Page 245 - ExtendSim User Guide
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Batching and Unbatching 219
Preserving the items used to create a batch
• Automatic.BehavesasPreservedvalueif“Preserveuniqueness”ischecked;otherwise behaves as Batched value.
Preserving the items used to create a batch
Before items are batched they may have properties such as attributes attached to them. By default, a reduced set of those properties is transferred to the new batched item, according to actions selected in the Properties tab of the Batch block. (For more information, see “Property options” on page 214.)
If it is important in your models to retain the attributes and priorities of the items that were batched, select Preserve uniqueness in the Batch block and in the Unbatch block. This marks the items in the batch as unique so that an Unbatch block can restore all of the items’ properties.
☞ For those properties that you want to retain, select the Preserved Value action in the Properties tab of the Unbatch block, as discussed in “Properties when items are unbatched” on page 218.
Do not select Preserve uniqueness unless the items have unique information attached to them, the items are not just temporarily batched, and you need to restore the items and their properties at a later point. Preserving uniqueness requires a lot more memory and slows pro- cessing time.
Both blocks choose to preserve uniqueness
The consequences of selecting, or not selecting, Preserve uniqueness in both the Batch and Unbatch blocks are:
• IfthePreserveuniquenessoptionischecked,thebatchistemporary.Theoriginalmembers of the batch are stored when the batch is created and they can be restored when the item rep- resenting the batch is unbatched. Examples include batching a group of parts together to pro- cess them as a group and later unbatching them to continue processing individually, or batching an item with a resource and later returning the resource item with an Unbatch block.
• IfthePreserveuniquenessoptionisnotchecked,theitemsusedtomakeupthebatchare destroyed when the batch is created. The batch, represented by a new item, is permanent and the original items cannot be restored. Examples include batching items together into a box for final shipping, or batching an order with the required inventory.
☞ If a Batch block is set to preserve uniqueness, the unique identity of the items will only be restored upon unbatching. While batched, the attributes of the unique items will be combined into one set of attributes, as specified by settings in the Batch block’s Properties dialog.
Either block chooses to preserve uniqueness
To restore the items with their properties intact, the option to “Preserve uniqueness” must be selected in both the Batch and Unbatch blocks. There are special outcomes if “Preserve uniqueness” is selected in either the Batch or the Unbatch block, but not in both blocks:
• If Preserve uniqueness is selected in the Batch block but not in the Unbatch block, the behavior of the Unbatch blockdepends on whether or not “Duplicate preserved items” is selected. If “Duplicate preserved items” is not selected, the preserved items travel with the first item that leaves the Unbatch block’s top output connector. All the other items leaving the Unbatch block will be identical and not contain any information about the preserved
Discrete Event

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