qt5 - Separate composition of mixture models in GUI

[tcbennun]

ported from JIRA, SASVIEW-973:

---

Torin Cooper-Bennun, 26 July 2018 11:10

Mixture models (a.k.a. sum/multiply models, for current intents and purposes) separate parameters of their component models using prefixes (A_sld, B_sld, and so on).

We are on the way to using sub-headings in the parameters table instead (see ​SASVIEW-966 [and comments in trac, #475]). To implement this for mixture models, an intermediate layer (upon model loading) is needed to extract the parameters by component and display them without prefixes; then, when they are manipulated, translate from the non-prefixed version to the prefixed version, in order to interact with the model itself correctly.

The first step seems okay, since modelinfo, I think, contains the necessary information to get the name of the model component from the parameter's prefix.

The second step is a bit more involved. One possibility is to have each non-prefixed parameter in the Qt model be associated with a data item which contains the real parameter name. Whatever happens, various routines will need updating to deal with this case, because currently only the item's text is used to identify the parameter.

[tcbennun]

In the ESS_GUI_beta_approx branch, product model parameters are all shown separated by constituent model:

[tcbennun]

Product model params are now separated by P(Q), S(Q) by subheadings in ESS_GUI.

Doing the same for mixture models is a big task…