Gaussian Curve Fit using Scipy ODR

[Tuxedo]

Looks like your GaussModelConstant function may not be properly defined. According to the scipy odr documentation (https://docs.scipy.org/doc/scipy/reference/odr.html) the fitting function has the following form:

def f(B, x):
    '''Linear function y = m*x + b'''
    # B is a vector of the parameters.
    # x is an array of the current x values.
    # x is in the same format as the x passed to Data or RealData.
    #
    # Return an array in the same format as y passed to Data or RealData.
    return B[0]*x + B[1]

If you correct that and use init_guess = [1400, 270, 10, 200] it works fine.