Deriving Parameters

Deriving Parameters

Parameters can be derived (calculated) based on existing data.

On the left, the FACS data for the derived parameter can be selected. The parameter can also be applied to all FACS data files in the list at once, by selecting the check box on top.

The right top window lists already existing derived parameters for the currently selected FACS data file. In the example shown above, that parameter is called 'F+S'. Additionally, the parameters for the calculation are shown: FSC and SC are added, the result is divided by 2.0 and the maximum value 8and also range) of the parameter is defined as 10 000.

The bottom right panel allows the definition of a new calculated parameter.

A new derived parameter

Option	Explanation
Name	The name of the parameter; this will also shown in plots, statistics, etc.
Calculation	Next, the involved parameters and mathematical operation can be defined. The parameter on the left is used for an mathematical operation with the right parameter, or a manually entered value. The basic math operations addition, subtraction, multiplication and division are supported.
Adjustment factor	The next value is meant to adjust the result. For example when adding to parameters it might make sense to divide the result by 2.0 to bring the value back into the standard range of the parameters.
Maximum value	This is the maximum possible value. values higher than that are cut at that value. This is important for multiplication and division oprations, as those values can get unmanagable high.
Division by zero	This option is only available when division is used as mathematical operation. FACS data might contain zero values. As division by zero is not defined, a substitute value has to be used - FACS parameters can't be without a value. Please enter the value that shall be chosen as substitute.

Organizing derived parameters

After definig the parameter, click "Add" to add the parameter to the FACS data file(s). Existing parameters can be deleted as well. Please note that deleting a parameter might affect regions, gates and plots - control these carefully after deleting a parameter!