Understanding Circular System Resolution

The analytic calculation engine uses the process of iteration to attempt to resolve all of an analytic model's circular systems. You set the iteration parameters by using the General tab of the analytic model's properties. If the cells converge on a solution within the iteration parameters, the circular system is resolved. If the cells do not converge on a solution within the iteration parameters, the analytic calculation engine returns an error. All cells within the circular system remain unresolved.

Note:

Because you enable or disable iteration for all circular systems, you cannot enable or disable iteration for a particular circular system.

When you enable the resolution of circular systems through iteration, you must select one of the following iteration options:

  • Maximum number of iterations

    When the values of the cells have not changed more than the specified maximum amount, the circular system is considered to be resolved.

  • Maximum change in values

    When the analytic calculation engine has calculated the cells within the circular system for the specified maximum number of times, the circular system is considered to be resolved.

Example of Resolving a Circular System

In this example, an analytic model contains the following formulas (for simplicity, assume that each data cube contains only a single cell):

  • Formula for BONUS data cube:

    BONUS_PERCENTAGE * NET_INCOME

  • Formula for EXPENSE data cube:

    SALARY + BONUS

  • Formula for NET_INCOME data cube:

    INCOME - EXPENSE

First, the analytic calculation engine determines that this is an indirect circular formula because the data cubes' formulas refer indirectly to those same data cubes.

Next, the analytic calculation engine analyzes the calculation conditions of the cells within this indirect circular formula and determines that these cells create a circular system. This is because the cells within this formula are dependent on the same values of those same cells.

Assuming that the value for the BONUS_PERCENTAGE cell = 5, the value for the INCOME cell = 10000, and the value for the SALARY cell = 6000, then the circular system is resolved when the analytic calculation engine iterates until it returns these solutions:

  • Cell for BONUS = 190.48.

  • Cell for EXPENSE = 6,190.48.

  • Cell for NET_INCOME = 3,809.52.

If you plug these values into the preceding formulas, each formula is true: the left side of the formula is (almost) equal to the right side of the formula. Once this occurs, the circular system is considered to be resolved.