Define Eigen

The Define Eigen node is used to define the variables needed by GF, which will be used for Eigen calculations or other Conditions. Then each eigen value will create one feature instance, and each feature instance will be assigned with related devices.

To add variables for eigen specification, you can use either of the following methods:

• Use Parser Variable from CLI or Configuration.
• Use System Data
  
  
  

Add Variable From Parser Variable

By default, From Parser Variable is selected in the UI.

1. Select the Device from which you want to retrieve configuration data.

2. Input the relevant CLI command or, alternatively, select the Configuration to fetch the device’s configuration.

3. Click Retrieve to fetch the device's configuration data for variable parsing.
   
   By default, the system selects Live Data as the source. If you need to change this, click the Settings icon and choose a different data source.
   
   

   Note: The parser is self-contained: whether you choose an existing parser or create a New Parser, it remains within the GF and can be adjusted further using Edit Parser.

4. To select a parser from the dropdown either:
   1. Choose an existing parser from the Parser Library.
      (or)
      Create a new parser by selecting the +New parser option. For more details, refer to the topic Select Parser from the Quick Intent.
      

      If the selected parser is not the correct one, follow these steps to modify it: From the Edit drop-down menu, select Edit Parser.

      
      
5. Add Variables to the Eigen Variable table for further configuration, follow these steps: 
    
   

   1. In the Variable View, you can select an individual variable and use menu to add that variable to the Eigen Variable table. For example, $group_id, $virtual_ip, and $state is added to the Eigen Variable table.

   2. To set the Eigen Variable, select each Variable checkbox you wish to set as eigen variable.
      

6. To change the variable Display Name, click the Variable to see the Change Display Name dialog.
   

7. To delete the variable, hover over the variable you wish to delete and then click the delete button.
   

Add Variable from System data

1. Select the From System Data from the dropdown to add variables.
2. Select the device property i.e., Hostname as variable.
3. Click Add Variable >> to add the variables in Eigen Variable table. You will see the Hostname is added under the Device Property.
   
4. To set the Hostname as an Eigen Variable, select the checkbox.
   

Add Compound Variable

The system provides built-in functions for you to define compound variables to convert predefined variables in terms of variable types, units, values, etc. You can create compound variables from the currently selected variables. In this example, L3 Topology variables are used to create a compound variable.

1. Select L3 Topology from the drop-down list and select all of the four variables.
2. Select the Local Interface and Neighbor Interface from the available options. This Device and Neighbor Device are by default selected.
   
   
3. Click Add Variable >> to add the selected variable to the Eigen table.
4. Go to the Data Operation function and select Add Compound Variable from the dropdown.
5. To add the Compound Variable, follow these steps:
   1. In the Variable Name field, enter the desired variable name.
   2. In the Definition field:
      1. Use the dollar sign ($) to select available variables from the dropdown menu.
      2. Combine two variables by separating them with a plus sign (+).

This Compound Variable will uniquely identify a local interface across the network if the device hostname is unique.

Table Keys Matching

You can define multiple Paired Keys for merging, ensuring that columns from different tables are correctly paired for the merge.

More Settings for Eigen Variable

Selected Eigen variables, marked via checkboxes in the table, are grouped together. Eigen values are used to group devices with similar characteristics into a single group. To group a device with its Layer 2 neighbors, a different method may be needed to form an Eigen group, for example:

Eigen variable: (this device, local interface, neighbor device, neighbor interface)

To create a variable group, follow these steps.

1. Select L2 Topology from the dropdown menu.

2. Select the Local Interface and Neighbor Interface from the available options. This Device and Neighbor Device are by default selected.

3. Click Add Variable >> to add the selected variable to the Eigen table. The variable will appear under the L2 Topology section.

4. Select all checkboxes under the L2 Topology section to set as the Eigen Variable.

5. Click More to view the Eigen Variable settings for grouped variables.