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To specify custom fit function formula, press
Add button and select
Custom Equation in popup menu.
Enter your formula in
y(x)= text field below. Use
x as fit function argument. See formula syntax.
You may recall last entered custom fit functions using
Recently Used Custom item in
Add popup menu.
You can introduce fit function parameters with any names (except argument
x, and constants like
pi, etc, full list: predefined constants):
Aare different parameters).
_sign. You can use numbers in the middle or in the end of the name:
a1, a_1, A1, a1t, but the names like
1aare not allowed.
The parameters you introduce will automatically and immediately occur in parameters list, you do not need to enter parameters names in the list manually.
Random values are used as the initial values of parameters. Do not forget to set more relevant initial values, otherwise fit algorithm may fail.
You can adjust Parameters using mouse wheel (scrolling): Hold Ctrl (Cmd on Mac) key and scroll. If Shift key is also pressed the step for one wheel 'click' will be increased.