Broad peak model documentation says $I(q) = \frac{A}{q^n} + \frac{C}{1 + (|q - q_0|\xi)^m}^p + B$ but the implementation is
z = abs(q - peak_pos) * correlation_length
with errstate(divide='ignore'):
inten = (porod_scale / q ** porod_exp
+ peak_scale / (1 + z ** width_exp)) ** shape_exp
I suspect both should be changed, with $I(q) = \frac{A}{q^n} + \frac{C}{(1 + (|q - q_0|\xi)^m)^p} + B$ implemented as
z = abs(q - peak_pos) * correlation_length
with errstate(divide='ignore'):
inten = (porod_scale / q ** porod_exp
+ peak_scale / (1 + z ** width_exp) ** shape_exp)
Also note that the DAB model is not identical to broad peak with $m = p = 2$ unless $A=0$, $q_0 = 0$ and $C = \xi^3$
Broad peak model documentation says$I(q) = \frac{A}{q^n} + \frac{C}{1 + (|q - q_0|\xi)^m}^p + B$ but the implementation is
I suspect both should be changed, with$I(q) = \frac{A}{q^n} + \frac{C}{(1 + (|q - q_0|\xi)^m)^p} + B$ implemented as
Also note that the DAB model is not identical to broad peak with$m = p = 2$ unless $A=0$ , $q_0 = 0$ and $C = \xi^3$