Changes between Initial Version and Version 1 of Ticket #1113, comment 1


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Timestamp:
Jul 3, 2018 5:09:48 AM (6 years ago)
Author:
richardh
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  • Ticket #1113, comment 1

    initial v1  
    1 Historically in sasview constraint are envisaged as linking parameters between different fit pages, thus the constraints tab wall only appear if there is more than one fit page. 
     1Historically in sasview constraint are envisaged as linking fitting (not fixed) parameters between different fit pages, however saasview was changed some while ago so that the constraints tab will appear if there is only a single fit page. 
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    3 Constraints within one fit page are OK, BUT in sasview they are not applied inside polydispersity integration loops. Thus if a user set shell_thickness=0.2*radius, where radius is polydisperse, then shell_thickness is constant at 0.2*mean_radius. It would be good to warn users if they attempt this. 
     3Constraints within one fit page are OK, BUT in sasview they are not applied inside polydispersity integration loops. Thus if a user set shell_thickness=0.2*radius, where radius is polydisperse, then shell_thickness is constant at 0.2*mean_radius. It would be good to warn users if they attempt this.  
     4 
     5Users that need constraints of this type are encouraged to generate their own plugin models. However now that all polydispersity integrations are removed from the models themselves, it might be possible for sasview to allow this at some future point (i.e. to apply relevant constraints when setting up the lists of coordinates & weights for the integrations). 
    46 
    57Historically, the only indication on a fit page that a parameter is constrained (without looking back at the constraints tab) is that the error box for that one says "nan". This is likely because users can hit "fit" on either an individual fit page for a fit to just that data set (when the parameter is not actually constrained but freely adjusting) or hit "fit" on the constraints tab for a fit to multiple data sets.