Creating a Horizon
Description
To create a new horizon in the Model Tree:
Select the position in a Declaration Section where the new horizon should be inserted
From the Edit menu select Insert – Other (or press the
<Insert>
key)In the dialog box select
Horizon and press OK
Enter a name for the new horizon
Press
<Enter>
to create the new horizon (or press<Esc>
to abort the operation)
The newly created horizon is not yet ready for use, because you should at least specify some mandatory attributes. To modify the attributes of the newly created horizon:
Press
<Enter>
or double click on the horizon node.
The most commonly used attributes of a horizon identifier are discussed below.
SUBSET OF
: TheSUBSET OF
attribute should be specified in order to declare a subset. Thewizard will display the Set Dependency Tree of your model and allows you to select one or more sets.
INDEX
: TheINDEX
attribute is the place to declare indices in the current horizon. Thewizard allows you to declare new index, delete or rename an existing index or move an index to another set.
PARAMETER
: ThePARAMETER
attribute is like theINDEX
attribute except that it allows you to declare scalar element parameters (instead of indices) in the current horizon.DEFINITION
: TheDEFINITION
attribute is mandatory and should be used to determine the ordering of the periods in the horizon.CURRENT PERIOD
: TheCURRENT PERIOD
attribute is used to specify the first period of the planning interval. TheCURRENT PERIOD
attribute together with theINTERVAL LENGTH
attribute determine the generation of constraints and variables in your model. Thewizard will display an Identifier Selection Dialog box containing all element parameters that are defined over the current horizon.
INTERVAL LENGTH
: TheINTERVAL LENGTH
attribute is used to specify the number of periods that should be considered during the model generation. If not specified, all periods from the current period onward are part of the planning interval.
Remark
A horizon is a special kind of set. When variables and constraints are indexed over a horizon, AIMMS automatically restricts the generation of these constraints and variables to periods within the planning interval.
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