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Model Validation (Miscompare)

Quantum XL uses a proprietary math engine to provide rapid Monte Carlo simulations. To ensure that Quantum XL's calculations are the same as Excel's calculations, each time you run the model a small number of simulations are run using both Excel and Quantum XL, and the results are compared. If Excel's equation engine doesn't match the Quantum XL engine, you will receive a miscompare or syntax error warning. The warning is usually caused when the equation you are using is not supported by Excel and is supported by Quantum XL or vice versa. It can also be caused by using text arguments which are not supported in Quantum XL.

Quantum XL validates models in two steps. First, it checks the model for syntax errors. After that, it runs a specified number of simulations and compares the results from Quantum XL's calculation engine to results returned by Excel's calculation engine.

Syntax Errors

A syntax check is performed as a first step in model validation. Quantum XL checks all cells used in the model for syntax that is not supported in Quantum XL. Syntax errors may occur for the following reasons:

  1. Function is not supported in Quantum XL (example: VAR function is not supported in Quantum XL). List of Supported Functions.

  2. Function with textual arguments (example: '=CONVERT(68, "F", "C")' )

  3. Concentration operator '&' (example: '=A1 & A2' )

  4. Array formula. An array formula is a formula that can perform multiple calculations on one or more of the items in an array. Excel displays them enclosed in curly braces { }. This type of formula is not supported in Quantum XL.

Szntax Errors

Miscompare

The second step of model validation is to check for differences between the Quantum XL and Excel calculation engines on a given model. Quantum XL will run a specified number of simulations and check for the differences. How many simulations Quantum XL will run and the sensitivity level can be customized (see Model Validation Settings).

A miscompare check is performed only for cells that are marked as outputs. It is possible that a miscompare occurs for an output that is actually correct. In this case, the error is in one of the cell precedents. However, this type of error is usually reported during the Syntax check.