Index operation
Used to sum or multiply values, or finding the maximum or minimum value, of a non-scalar Block. When the target object is 2-dimensional, you must specify which index list to perform the operation on.
Creating an index operation
From the Projects window
- Expand the Project to which you wish to add the index operation by clicking the + symbol next to it. Right-click on ‘Blocks’, or a sub-system in ‘Blocks’, and select Index Operation from the pop-up menu.
From the Matrix window
- Right click an empty diagonal cell of the matrix and select Index Operation from the the pop-up menu.
From the Blocks window
-
Place the mouse anywhere over the area of this window and right-click on it. Select New | Index Operation from the pop-up menu, or
-
In the title bar, select Index Operation from the Type drop-down list and click on the
button.
Editing an index operation
| Note | Most block properties can be edited directly in the Blocks window. |
The block editor is shown by right-clicking the block in a window and selecting Edit. In the Blocks window, you can also show the block editor by selecting the block and clicking the 
button, or by double-clicking the right-most “validation” column of the block.
The block editor has three tabs:
Properties
This page lets you edit basic properties such as name, sub-system and base unit. See editing properties for more information.
Values
The values page let you select the target object and which operation to perform.
Operation - Choose the operation to perform. You can compute the sum, the product, the minimum or the maximum value of an object.
Object - Select the object to perform the operation from this list of all the available non-scalar objects.
Index List - When you select a 2-dimensional object, you specify here which index list to perform the operation over.
Example
The expression doses is two dimensional. At a specific time point is has the following values:
| Contaminant | Person | Value |
|---|---|---|
| Lead | Man | 4 |
| Arsenic | Man | 1 |
| Mercury | Man | 6 |
| Lead | Woman | 3 |
| Arsenic | Woman | 8 |
| Mercury | Woman | 6 |
An index operation which finds the maximum over the Person indices would yield:
| Contaminant | Value |
|---|---|
| Lead | 4 |
| Arsenic | 8 |
| Mercury | 6 |