To specify custom fit function formula, press Add
button and select Custom Equation
in popup menu.
y(x)=
text field below. Use x
as fit function argument. See Expression Syntax for details.Recently Used Custom
item in Add
popup menu.
You can introduce Fit Curve parameters with any names except argument x
, and constants like e
, pi
(see predefined constants for details):
a
and A
are 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 1a
are not allowed.The parameters you introduce in formula 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 in table using mouse wheel scrolling when mouse cursor is on the desired parameter: Hold Ctrl key (Cmd key on Mac) and scroll. If Shift key is also pressed the parameter step for one wheel 'click' will be increased.