Importing and Exporting Models

Tetra allows importing and exporting of model data, or subsets of model data which is useful for the following purposes:

To perform any of these tasks first export the model or a part of it to a file, and then import the data into a new or existing model.

Exporting Models

To Export a model, choose Export... under the File menu. Optionally specify which alternatives, criteria, and decision makers (GDM only) to export in the filter dialog that appears (shown below), and then click 'Export To File...' to specify a file for the exported data. There is no filtering option for reference alternatives and reference ratings. All reference alternatives and reference ratings are exported.

(Note that in SDM the 'Decision Makers' part of the dialog is not shown.)

Importing Models

To Import a model a new or existing model must already be open. If the opened model contains data, the import process will merge the incoming data according to the rules you specify.

Select Import... under the File menu. The following dialog will be displayed in SDM. (GDM specific options are explained in the next heading below.)

The merge rules for the import must now be specified; Tetra will import alternatives, criteria, ratings, weightings, decision makers (GDM), reference alternatives, and reference ratings from the file you specify. You must indicate what action must be taken if a given element already exists in the open model (If Item Exists column) and what action to take if no such item exists in the open model (If Item Does Not Exist column).

The specified merge rule for alternatives also applies to reference alternatives. Similarly the merge rule for ratings also applies to reference ratings.

Once you have specified the import options as desired, press Import File... to select the file from which to import data. Note that it is not possible to undo import operations.

The meaning and behaviour of import options are explained in the sections below.

'If Item Exists'

Actions possible for importing a model item that already exists are as follows:

Use Existing: Keep the item that exists in the model, and ignore the item specified in the import file.

Replace Existing: Import the item specified in the input file and replace the existing model item.

Prompt For Action: Ask what action to take for each item that is encountered both in the imported file and in the opened model. This will occur as the model is being imported.

Example The import file contains a criterion called 'Cost' and the model also contains a criterion called 'Cost' at the node of the criteria tree currently being parsed. We choose 'Replace Existing' to import the 'Cost' criterion from the file along with its sub-criteria, ratings, and weightings. The 'Cost' criterion that previously existed in the model is removed.

'If Item Does Not Exist'

Actions possible for importing a model item that does not already exist are as follows:
Create New: Import the item from the file into the open model.

Do Not Create: Do not import the item.

Prompt For Action: Ask what action to take for each item that is encountered in the imported file that does not exist in the model.

'Rating Alternatives' and 'Weighting Criteria'

These import options appear under 'Ratings and Weightings' and apply to the alternatives referenced by ratings, or the criteria referenced by weightings. For example, it may be possible that an alternative on a rating being imported does not exist in the open model. You can choose to have it automatically created ('Create New'), or to ignore it ('Do Not Create') in which case the alternative will not appear on the imported rating.

Importing Models in GDM

Importing models in GDM is only available to model owners. The import options appear as shown below:

Two additional options are available for import in GDM.

'Reassign To current decision maker' checkbox: Checking this option means that all imported ratings and weightings will be imported for the current decision maker rather than the decision makers to which they originally belonged. Note that restrictions on the number of ratings and weightings that can be created under a given node of the criteria tree still apply; a rating or weighting may fail to be imported if other measurements already exist at the given node of the tree.

Import Decision Makers that do not exist in the open model: Here you have the choice of importing decision makers that are specified in the import file. Note that existing decision makers in the open model cannot be modified.