Because Vensim is focused on building feedback models, it flags variables that are not used anywhere (and therefore not part of any feedback loop). These flags are intended to help you catch omissions you might have made. They do not prevent simulation of the model.
If you have defined a variable and the variable is not used you will get a message:
USE FLAG: "profit" is not used in the model.
You can stop this message from being reported by marking the variable as a Supplementary variable either by checking the Supplementary box in the Equation Editor or adding in a Supplementary field in the Text Editor as in:
profit = revenue - cost
~ $ ~ Companies Profits - not used ~ :SUP |
If you use a variable that has been marked as Supplementary (even in the equation for another Supplementary variable) you will get a message when you check the model as in:
USE FLAG: The supplementary variable "profit" is used.
Simply remove the supplementary marking from the variable.
