Changeset 8d2df05 in sasmodels


Ignore:
Timestamp:
Mar 28, 2019 10:35:55 AM (6 months ago)
Author:
smk78
Branches:
master, core_shell_microgels, magnetic_model, ticket-1257-vesicle-product, ticket_1156, ticket_1265_superball, ticket_822_more_unit_tests
Children:
6607260
Parents:
c0136c72
Message:

Added note to smearing help. Closes #833

File:
1 edited

Legend:

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  • doc/guide/resolution.rst

    r0db85af r8d2df05  
    1 .. sm_help.rst 
    2  
    3 .. This is a port of the original SasView html help file to ReSTructured text 
    4 .. by S King, ISIS, during SasView CodeCamp-III in Feb 2015. 
     1.. resolution.rst 
     2 
     3.. This is a port of the original SasView html help file sm_help to ReSTructured  
     4.. text by S King, ISIS, during SasView CodeCamp-III in Feb 2015. 
    55 
    66 
     
    1717resolution contribution into a model calculation/simulation (which by definition 
    1818will be exact) to make it more representative of what has been measured 
    19 experimentally - a process called *smearing*. Sasmodels does the latter. 
     19experimentally - a process called *smearing*. The Sasmodels component of SasView  
     20does the latter. 
    2021 
    2122Both smearing and desmearing rely on functions to describe the resolution 
     
    2930for the instrument and stored with the data file.  If not, they will need to 
    3031be set manually before fitting. 
     32 
     33.. note:: 
     34    Problems may be encountered if the data set loaded by SasView is a  
     35    concatenation of SANS data from several detector distances where, of  
     36    course, the worst Q resolution is next to the beam stop at each detector  
     37    distance. (This will also be noticeable in the residuals plot where  
     38    there will be poor overlap). SasView sensibly orders all the input  
     39    data points by increasing Q for nicer-looking plots, however, the dQ  
     40    data can then vary considerably from point to point. If 'Use dQ data'  
     41    smearing is selected then spikes may appear in the model fits, whereas  
     42    if 'None' or 'Custom Pinhole Smear' are selected the fits look normal. 
     43     
     44    In such instances, possible solutions are to simply remove the data  
     45    with poor Q resolution from the shorter detector distances, or to fit  
     46    the data from different detector distances simultaneously. 
    3147 
    3248 
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