Parameters¶

We define a parameter as one of a set of variables that form the parameter space over which the optimisation takes place, i.e. can be varied by the fitting engine. Parameters are of a single type: Python float (C++ double). Parameters must be declared in an init section so that the fitting framework can find out what they are, i.e. you see them in the GUI.

To declare a parameter use the declareParameter() method that takes a name & and an optional default value:

from mantid.api import *

# Remember to choose either IFunction1D or IPeakFunction
class Example1DFunction(IFunction1D): # or IPeakFunction

    def init(self):
        # Parameter with default value 1.0
        self.declareParameter("Constant", 1.0)

If not supplied the default value is 0.0