Broad Peak Model (Trac #724)

[sasview-bot]

Idea is to build a generalised Broad Peak Model with the following function: I(q) = scale_p/pow(q,exponent)+scale_l/pow((1.0 + pow((fabs(q-q_peak)*length_l),exponent_l) ),exponent_p)+ background

For qpeak = 0, m = 2 and p = 1 one gets the Lorentz model. For qpeak = 0, m = 2 and p = 2 The Broad-Peak model is identical to the Debye-
Anderson-Brumberger (dab) model. Like this you then can save these two models.

Migrated from http://trac.sasview.org/ticket/724

{
    "status": "assigned",
    "changetime": "2019-03-03T01:52:56",
    "_ts": "2019-03-03 01:52:56.861190+00:00",
    "description": "Idea is to build a generalised Broad Peak Model with the following function: I(q) = scale_p/pow(q,exponent)+scale_l/pow((1.0 + pow((fabs(q-q_peak)*length_l),exponent_l) ),exponent_p)+ background \n\nFor qpeak = 0, m = 2 and p = 1 one gets the Lorentz model. For qpeak = 0, m = 2 and p = 2 The Broad-Peak model is identical to the Debye-\nAnderson-Brumberger (dab) model. Like this you then can save these two models.",
    "reporter": "dirk",
    "cc": "",
    "resolution": "",
    "workpackage": "SasModels New Model",
    "time": "2016-10-07T15:26:40",
    "component": "sasmodels",
    "summary": "Broad Peak Model",
    "priority": "major",
    "keywords": "",
    "milestone": "sasmodels Next Release +1",
    "owner": "none",
    "type": "enhancement"
}

[butlerpd]

Trac update at 2019/03/02 00:52:27: butler changed workpackage from "SasModels Redesign" to "SasModels New Model"

[butlerpd]

Trac update at 2019/03/03 01:52:56:

• butler changed owner from "dirk" to "none"
• butler changed status from "new" to "assigned"

[butlerpd]

@dehoni - I believe this model does exist in sasmodels and is called by this name broad_peak. Not sure if it was added in response to this ticket or otherwise? Suggest this ticket be closed unless somebody knows how this is different from the existing model.

[dehoni]

The PR makes the small change and introduces an outer power exponent to produce other profile shapes than simple Lorentzian just like the sasfit_broad_peak function (https://github.com/SasView/sasfit-models/blob/7e0abfb7e20e8ffef849de4a27818a4241aecdd2/sasmodels/models/sasfit_broad_peak.py).