Error Messages/41336

Example error text

The 'Optlowerbound' attribute of Decision 'Inventory_goal' is defined as an unindexed list, which is ambiguous since Decision 'Inventory_goal' is declared to be 2-dimensional (i.e., its OptDimensions attribute lists 2 indexes).

Cause

You have a multi-dimensional decision variable with the indicated attribute (e.g., Optlowerbound) set to an unindexed list. Let's look at an example:

 Decision Inventory_goal
   OptDimensions: [Product1,Time]
   OptLowerBound: [150, 100, 50]

Note that there is a list of values listed in the OptLowerBound. But does this indicate that the lower bound varies along the Product index, or does it vary along the Time index? Well, from this it isn't possible to tell. Hence, the OptLowerBound as specified is ambiguous, and this error message results.

Remedy

First, if your lower bound does not vary with any indexes, drop the list entirely and set it to a single value.

Otherwise, change OptLowerBound to an expression that evaluates to an array having the correct index. For example, if you want these to be the lower bounds for different products, then you could set:

OptLowerBound: Array(Product1, [150, 100, 50])

A preferable way to do this is place the expression in a separate variable, e.g.:

 Constant Inventory_goal_lb := Table(Product1)(150, 100, 50)
  
 Decision Inventory_goal
   OptDimensions: [Product1, Time]
   OptLowerBound: Inventory_goal_lb

See Also

• Time
• DefineOptimization
• Function calls and parameters
• Classes of variables and other objects
• Indexes and arrays: An introduction