' File to fit a simple stragight line to data in TOPAS
do_errors

xdd data.xy
    x_calculation_step = Yobs_dx_at(Xo); 'compute fit at observed points
    weighting 1 
    
    prm m  5.3`_0.793725393
    prm c -4.5`_2.17370651
    
    fit_obj = m*X + c; 

    'penalties_weighting_K1 1
    'penalty = c^2;
    
C_matrix_normalized
{
                             1   2
m                      1:  100 -91
c                      2:  -91 100
}