ZFdipole.py

# Mantid Repository : https://github.com/mantidproject/mantid
#
# Copyright © 2019 ISIS Rutherford Appleton Laboratory UKRI,
#   NScD Oak Ridge National Laboratory, European Spallation Source,
#   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
# SPDX - License - Identifier: GPL - 3.0 +
# pylint: disable=invalid-name, anomalous-backslash-in-string, attribute-defined-outside-init

from mantid.api import IFunction1D, FunctionFactory
import numpy as np


class ZFdipole(IFunction1D):

    def category(self):
        return "Muon\\MuonSpecific"

    def init(self):
        self.declareParameter("A0", 0.2)
        self.declareParameter("BDip", 10)
        self.declareParameter("LambdaTrans", 0.2, 'Lambda-Trans (MHz)')
        self.addConstraints("BDip > 0")
        self.addConstraints("LambdaTrans > 0")

    def function1D(self, x):
        A0 = self.getParameterValue("A0")
        BDip = self.getParameterValue("BDip")
        LambdaTrans = self.getParameterValue("LambdaTrans")
        gmu = 2 * np.pi * 0.01355342
        Omega = gmu * BDip
        return A0 * (1. / 6) * (1 + np.exp(- LambdaTrans * x) * (
            np.cos(Omega * x) + 2 * np.cos(1.5 * Omega * x) + 2 * np.cos(0.5 * Omega * x)))


FunctionFactory.subscribe(ZFdipole)