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6.1.3 Iterative Calculations

   

Normally, a formula in a given cell should not depend on that cell itself, either directly or indirectly. Such a condition is called a cyclic dependency. When cyclic     dependencies exist, the rule for natural order recalculation as described above does not make sense. When you enter a formula which creates a cyclic dependency, the message ``Cycle!'' is displayed in the cell.

In some cases cyclic dependencies are useful in that they can represent iterative calculations, which NExS supports. Iterative calculation is useful when two or more cells mutually depend on each other such that each time they are recalculated, their values become closer and closer to the desired answer.

When the Iteration Limit field in the Recalc Options     dialog box is set to a non-zero value and Method is set to Foreground, iterative calculation is enabled. In this mode, NExS will make multiple recalculation passes, still preserving the natural order and minimal recalculation rules described above, until either the iteration limit has been reached or, if constraint checking is enabled, until all constraints are satisfied. The @INIT function helps perform iterative calculations.  


next up previous contents index
Next: 6.1.4 Constraint Checking Up: 6.1 How NExS Calculates Previous: 6.1.2 Method of Recalculation

NExS User's Guide, Version 1.4.5
Grey Trout Software
11 April 1999