.. index:: UserFunction
A UserFunction is defined by a string formula. The formula is assigned by setting string attribute Formula:
`` "name=UserFunction, Formula = h*sin(a*x), h=2, a=1"``
Formula must use 'x' for the x-values. The fitting parameters become defined only after the Formula attribute is set that is why Formula must go first in UserFunction definition.
.. attributes::
.. properties::
.. categories::
.. sourcelink:: :h: Framework/CurveFitting/inc/MantidCurveFitting/Functions/UserFunction.h :cpp: Framework/CurveFitting/src/Functions/UserFunction.cpp