This model is the optimization of the Formula Engine
model. The Dependencies Engine allows the user, basing on a certain formula
in the Cube, to write dependencies to tell the engine what values it needs
to calculate. For full description of the Dependency feature refer to
the *Dependencies* part of the *Formulas* section, as this is
simply a description of the engine.

It is important to know that dependencies values must be written correctly and it must be valid before it could work. However, the improvements that may be seen could easily be several orders of magnitude based on the complexity of your model and how many detail points one is trying to calculate and roll into aggregate. It is imperative to know that dependencies can only be written on Detail level formulas. If a formula can be written and performed at the Aggregate level or the 'ALL' level, then there is no need to write a dependency formula for that particular Cube.

In this example we have a formula in the Cube that computes
for *Sales* value by multiplying *Units* by *Price.* We
are going to tell the engine to consider only Detail members that has
a value for Members *Units* and *Price*.

1. In the PowerOLAP ribbon, select **Model**
tab and **Cubes**
command.

The **Cubes** dialog box is opened.

2. Select a Cube (in the example the
** Future Year Model** cube was selected)

then click on

Upon viewing the Formulas tab it contains a formula
that says **Sales= Units x Price**.

3. Click on the **Use Dependencies**
check box.

4. Select the **Dependencies** tab
and write a dependency formula as in the example:

The formula written above tells the engine to consider
only calculating this formula when there is a value for *Units*.

5. Check for Syntax errors by clicking
on the **Check Syntax** button.

Click **OK** button to return to the **Cubes** dialog box.

6. In the **Cubes** dialog box select
**OK**.

7. Referring back to the Slice click
**F9** or **Recalculate**
button to refresh or update the Slice.