Attributes and External Data in Generators

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You can add an assignment of an attribute, and choose the name of a preset attribute already defined or set it with an expression. Attribute values set with an expression are evaluated during simulation. For more information, see Attributes.

You can use the data in an Excel spreadsheet anywhere an expression may be used in the Generators dialog box. For example, Excel data may provide attribute values for each generated transaction, or to specify interarrival time periods in an Interarrival generator. iGrafx references data row by row for each transaction generation. You can map columns to transaction attributes or as an External Data attribute designated as x.column_title in any expression within the Generators dialog box.

Task	Procedure
Initialize an attribute for a generator	Each field contains a drop-down list of preset attributes defined. You can set the attribute value with an expression that is evaluated during simulation. On the Generators dialog box, click the Attribute Initialization tab. Select the generator you want to initialize attributes for. Click the Add button. Any attributes you have already created for the process diagram are available. If you need to create new attributes, click the button.
Reference generator data from an Excel document	Create an Excel spreadsheet containing columns of data for each possible type of data you want to use in a generator. In the Generators dialog box, click the External Data tab and select the Get Attribute data from external source check box. Browse to the Excel file you want to reference. If your Excel document contains multiple tables, choose the table from the Table drop-down list. Select a setting from the Reread Data Whenever drop-down list. From the Select Rows drop-down list, select the order in which rows are read on the spreadsheet, one row per generation. From the When Rows Exhausted drop-down list, select an action to take when all rows have been read. Optionally, select a column in the display window and click the Define Type or Assign to Attribute button to define a new Type for non-numeric data or assign table data to an attribute. If a column appears in bold, an attribute is already assigned. You can define a new Type for a column only if no conflicting Type definitions already appear. Control assignments on the Properties dialog box - Attributes page. You can use a column of data within the Generators dialog box. Go to that expression and use the External Data location attribute that corresponds to the Excel column.

Task

Procedure

Initialize an attribute for a generator

Each field contains a drop-down list of preset attributes defined. You can set the attribute value with an expression that is evaluated during simulation.

On the Generators dialog box, click the Attribute Initialization tab.
Select the generator you want to initialize attributes for.
Click the Add button. Any attributes you have already created for the process diagram are available. If you need to create new attributes, click the button.

Reference generator data from an Excel document

Create an Excel spreadsheet containing columns of data for each possible type of data you want to use in a generator.
In the Generators dialog box, click the External Data tab and select the Get Attribute data from external source check box.
Browse to the Excel file you want to reference.

If your Excel document contains multiple tables, choose the table from the Table drop-down list.
Select a setting from the Reread Data Whenever drop-down list.
From the Select Rows drop-down list, select the order in which rows are read on the spreadsheet, one row per generation.
From the When Rows Exhausted drop-down list, select an action to take when all rows have been read.
Optionally, select a column in the display window and click the Define Type or Assign to Attribute button to define a new Type for non-numeric data or assign table data to an attribute.

If a column appears in bold, an attribute is already assigned. You can define a new Type for a column only if no conflicting Type definitions already appear. Control assignments on the Properties dialog box - Attributes page.

You can use a column of data within the Generators dialog box. Go to that expression and use the External Data location attribute that corresponds to the Excel column.