About Matrix Rules

After it is defined, the matrix rule defines how the driving features and their options limit the constrained features and their options during product configuration.

A driving feature defines a primary feature variability criteria for a model version that somehow limits, or constrains, another model version feature's options. For example, if a Product Manager's goal is to sell several models of a car with various numbers of doors in specific trim packages, the car's driving feature—the trim packages—constrains the options available for door configuration.

A constrained feature is one that is somehow limited by the model version's driving features. For example, if a Product Manager wants to configure 2 door cars with either of the two available trim packages for sale in all geographical areas, the car's feature configuration might be constrained by the fact that the company cannot sell 2 door cars in India, thus negating the need to configure trim packages for that combination of features. See the example in External Rules.

For example, a driving feature could be the type of trim packages available for a car (for example, Sport and Premium). A constrained feature could be the number of doors available for the car (for example, 2 door, 3 door, or 4 door models). The matrix rule defines which trim packages can be used on cars with each numbers of doors. The following matrix rule enforces the requirement that Premium trim packages can only be used on 3 door and 4 door cars, while the Sport trim package can only be used on 2 door and 4 door cars.

In the matrix, the color of the cell indicates whether the combination of driving and constrained features and their options is available for use when configuring the model version. Gray cells indicate that the combination is not valid. White cells indicate that the combination is valid and is available for use when configuring the model version.

If you add an additional driving feature to a matrix rule—such as the colors available for each trim package—the matrix rule can also further define which combinations of these options are available or not during product configuration. So, in the following example, the Sport trim package is available in black on 2 door and 4 door cars, but is not available at all (in any color) on 3 door cars. The matrix rule also enforces the requirement that the Premium trim package is available in all color options for 3 door and 4 door cars, but not at all (in any color) on 2 door cars.

Driving features are considered cumulatively, meaning that the options for any additional driving features that are added to the matrix are evaluated as a subset of each of the options of the first driving feature that was added to the matrix. Constrained features are each considered separately with respect to the driving features. Each additional constrained feature appears in a separate row beneath the first constrained feature that was added to the matrix. The options available for the constrained features are not affected by each other. In the following example, whether 3 door cars are available in India does not affect whether 3 door cars can have the Sport or Premium trim packages.

The matrix rule reflects any other rules defined elsewhere that apply to the features and therefore affect the possible available combinations. These external rules cannot be overridden by the matrix rule.

Once the driving and constrained features are dragged and dropped into the matrix, the matrix rule shows which combinations of driving and constrained features are invalid or required because they are affected by an external rule. The matrix rule takes into account all variability rules defined for all driving and constrained features.

If an external rule defines any combination of driving and constrained features as incompatible (and thus invalid for selection during product configuration), this is indicated by a cell with a folded gray corner. When the user hovers over the folded gray corner, a message indicates which external rule makes the combination of features invalid. In this example, an external rule forbids versions of the car to be sold in Europe with Japanese language options. Only cars with European language options can be configured for sale in Europe.

If an external rule defines a combination of driving and constrained features as required (so that it must be selected during product configuration), this is indicated by a cell with a folded white corner. When the user hovers over the folded white corner, a message indicates which external rule makes that combination of features a required selection. In this example, cars with Japanese language options must be configured for sale in Asia.

The user defining the matrix rule can attempt to override an invalid combination by manually changing the color of the cell in the matrix, but the rule solver will still see the combination as invalid during product configuration.

A matrix rule can also define which driving and constrained feature/option combinations are the default selections when the model version is configured. The default selections are indicated with a blue star in the matrix cells. The Product Manager can override these default selections during configuration.

For example, a star in the matrix cell representing the Premium trim package in the color black indicates that, unless the Product Manager selects another door option at the time the model version is configured, the default number of doors for cars with Premium trim in black is 3. If a driving feature has two or more constrained feature options available as possible variations, only one of them can be made the default selection for that combination. In the following example, 2 is the default door selection for with Sport trim packages in red, while 4 is the default door selection for cars with the Premium trim package in gray. It is not necessary to define a default selection for any feature combination that has only one valid option available during configuration. In the example, cars with Sport trim packages in gray must be 2 door models, since it is the only valid option.

The matrix rule interface consists of several sections that help you define and display the matrix rule.

The variability list appears at the left side of the matrix display. It lists the variants and option groups that you can use to define the matrix rule. You can use the arrow icons to hide and reveal this list as needed while you are working with the matrix rule. Features that must be configured are indicated by an exclamation point (!) in the list. Features that do not have any options and features that are obsolete are not shown in the list.

The settings toolbar appears at the top right side of the matrix. It allows you to control how the matrix displays and to navigate through any conflicts to resolve them.

Setting Icon	Description
	Displays the rule in an editable matrix, with the driving features along the top axis and the constrained features along the side axis.
	Displays the rule in the structure view, with a column for driving features and a column for constrained features.
	Displays the number of conflicts (both internal and external) in the matrix rule.
	Navigates backward through the matrix rule's cells to the previous conflict.
	Navigates forward through the matrix rule's cells to the next conflict.
	Displays the matrix rule's legend, allows you to select whether internal conflicts are automatically identified when the matrix is opened and each time the user interacts with it, and the allows you to select whether the pictures associated with the features are shown in the matrix's headers.

When the matrix rule is displayed in the structure view as columns, it shows only the features selected as driving and constrained criteria. It does not show any available, non-available, or default feature/option combinations, or any conflicts among feature/option combinations.

Similarly, before any features are added to the matrix rule, there is a column for driving criteria and a column for constrained criteria into which you can drag and drop features.

The matrix action toolbar appears at the bottom right side of the matrix. It allows you to reset any changes you have made to the matrix rule and save your changes to the matrix rule.

Action	Description
Reset	Resets any changes you have made to the matrix rule since it was last saved.
Save	Saves all changes made to the matrix rule.