With the Go to the procedure, a convergence check is performed. It is checked whether a specific condition has been satisfied or a maximum number of iterations has been performed (Fundamentals: Go to procedure).
1. On the toolbar, click the 
button Open 'Procedure sequence' window.
The Procedure sequence window opens.
2. Add the Go to the procedure of the Miscellaneous category to the position of your choice in the procedure sequence (Setting up and starting the procedure sequence).
3. In the row of the inserted procedure, click the button in the Reference object(s) column.
The Procedure selection window opens.
4. Select the procedure you want to go to.
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Note: If you enter a group as Go to target, the procedure sequence is repeated from the first procedure of the group. |
5. Confirm with OK.
The procedure selected is adopted into the Reference object(s) column.
6. Make sure the added procedure is highlighted. Then, in the Operations section, click the Edit button.
The Parameters: Go to procedure window opens.
7. Make the desired changes.
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Element |
Description |
|
Number of iterations (minimum number) |
Minimum number of iterations as a termination criterion if convergence is reached. By specifying a number greater than zero, you can prevent cancelation during the first iteration and the Go to procedure from running (Fundamentals: Go to procedure). |
|
for at least one network object |
Select this option if you want to use the formula below it to define the convergence check threshold. Thereby x is the link attribute or matrix specified below. In the entry fields, enter the parameters of your choice (Fundamentals: Go to procedure). Note Convergence is considered reached when all matrix values or link attribute values in the network differ by less than the threshold from their previous value. Link attribute If you select this option, the attribute values of iteration step N and iteration step n-1 are compared. Thereby it is checked whether they have changed by less than the threshold defined and if the maximum number of iterations has been performed. Click this button to select an attribute (and subattribute, if available) in a separate window (Selection of attributes). Select matrix If you select this option, the matrix values of iteration step N and iteration step n-1 are compared. Thereby it is checked whether they have changed by less than the defined threshold during the last iteration and if the maximum number of iterations has been performed. Click the button to open the Select matrix window, in which you can select the matrix of your choice (Selecting matrices). |
|
The value of the network attribute |
Select this option to use a user-defined attribute of the network object for the convergence check. Click this button to select an attribute (and subattribute, if available) in a separate window (Selection of attributes). In the entry field, enter the comparative value of your choice. Note This option is recommended when you use a script to calculate the attribute value. |
|
Number of iterations (maximum number) |
Number of iterations as a termination criterion if convergence is not reached. |
8. Confirm with OK.
9. Execute the procedure (Executing procedures in the procedure sequence).
The convergence check is performed. Visum goes back to a previous procedure until convergence is reached or the maximum number of iterations is calculated.
