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• Pno% is the number that refers to the TeLiTab sets in the Data slot. Pno% should be an integer value or a parameter which is assigned an integer value and is the number of the TeLiTab set in the expressions' data slot.
• Npoints% is the number of points (x,y) that are given in direct definition.
• @ObjFn() refers to the Object from which data will be used.
• TeLiTab$ TeLiTab$ refers to the string parameter that contains the TeLiTab.
• Ndim% is the number of dimensions (or columns in the table...).
• "ColLab$_1" and @ObjColPar_1 refer to the column that will be used as the first parameter in the differentiation.
• "ColLab$_2" and @ObjColPar_2 refer to the column that will be used as the second parameter in the differentiation.
• Xint are the coordinates on which to compute the derivative dx/dy.
• DirivNo% is an optional argument by which can be indicated for which index of x_i the differential dx_i has to be computed. In y=f(x) DirivNo% should either be one (1) or omitted. If omitted or larger than Ndim%-1, the x_Ndim%-1 is assumed as differential

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1. See also Telitab access for a generic description on the use of TeLiTab data
2. Similar to other Data analysis functions, the DIFF is a convenient way to evaluate data. Please also look at these functions for syntax examples
3. Please realise the dataset provided to DIFF should be a function. Every x-value should have one y-value. Furthermore, in case of a multi-dimensional dataset you should provide a matrix of coordinates.
4. Extrapolation outside the x-range is performed parabolically.

Examples

Syntax 1: TeLiTab in Dataslot

In this example, the TeLiTab is addressed in the Dataslot. The function y is defined as y = DIFF(1, 2, "XC", "YC", x, 1) With the following Telitab set in the Data slot:

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y = DIFF(0, 4, 1, 1, 2, 4, 3, 9, 4, 16, x, 1) For x=2.5, this function returns

y=5

Syntax 3: TeLiTab in string

We have a relation:

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