Changeset b5846a10 in sasview


Ignore:
Timestamp:
May 28, 2015 1:11:14 PM (5 years ago)
Author:
smk78
Branches:
master, ESS_GUI, ESS_GUI_Docs, ESS_GUI_batch_fitting, ESS_GUI_bumps_abstraction, ESS_GUI_iss1116, ESS_GUI_iss879, ESS_GUI_iss959, ESS_GUI_opencl, ESS_GUI_ordering, ESS_GUI_sync_sascalc, costrafo411, magnetic_scatt, release-4.1.1, release-4.1.2, release-4.2.2, release_4.0.1, ticket-1009, ticket-1094-headless, ticket-1242-2d-resolution, ticket-1243, ticket-1249, ticket885, unittest-saveload
Children:
b327dd7
Parents:
63d314b
Message:

Work in progress

File:
1 edited

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  • src/sas/perspectives/fitting/media/fitting_help.rst

    r63d314b rb5846a10  
    132132.. ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ 
    133133 
     134.. _Adding_your_own_models: 
     135 
    134136Adding your own models 
    135137---------------------- 
     
    368370fit parameters between data sets (eg, to fix a background level, or radius, etc). 
    369371 
    370 If the data to be fit are in multiple files, load each file, select it in the  
    371 *Data Explorer*, and *Send To Fitting*. 
    372  
    373 If multiple data sets are in one file, load that file, *Unselect All Data*, then  
    374 select each dataset one at a time and Send To Fitting. 
    375  
    376 The result should be that for  
    377 n 
    378 datsets you have 2 
    379 n 
    380 graphs ( 
    381 n 
    382 of the data & model fit and  
    383 n 
    384 residuals plots). 
    385  
    386 IMPORTANT!  
    387 If you need to create a n 
    388 ew model with the new model wizard, or use a  
    389 model which is the sum of two existing models, go Fitting  
    390  
    391 Edit Custom Model  
    392 before 
    393 sending the data to the fitting engine. 
    394 The model will be available under  
    395 ‘ 
    396 Customised  
    397 Models 
    398 ’ 
    399 on  
    400 the FitPage. NB: the name will likely be abbreviated; eg,  
    401 ‘ 
    402 Peak  
    403 Gauss 
    404 Model + Absolute Power Law Model 
    405 ’ 
    406 will appear as  
    407 ‘ 
    408 PGM + APL 
    409 ’ 
    410 . 
    411 3. 
    412 Go to each Fit 
    413 Page in turn 
    414 and: 
    415  
    416 Select the required model. 
    417  
    418 Unselect all the model par 
    419 ameters. 
    420  
    421 Enter some starting guesses for the parameters (it may be helpful to remove the  
    422 residuals plots for clarity; go Graph  
    423  
    424 Show and untick graph windows as required). 
    425  
    426 Enter any parameter limits (recommended). 
    427  
    428 Select which parameters will refine (sele 
    429 cting all is probably a bad idea...). 
    430 4. 
    431 Select Fitting  
    432  
    433 Simultaneous Fit (this also selects the Complex Fit Engine). 
    434 5. 
    435 Go to the Simultaneous Fit page 
    436 and: 
    437  
    438 Select which datasets are to be fitted (which will probably be all of them or you wouldn’t  
    439 have  
    440 loaded them in!). 
    441  
    442 It is possible to tie parameters between datasets with constraints; eg, make the  
    443 Background in FitPage1 the same as the Background in FitPage2, and so on. To do this,  
    444 answer ‘yes’ to Add Constraints in the Fit Constraints box. 
    445  
    446 But note th 
    447 at SANSView only lets you constrain parameters that are refining. 
    448 6. 
    449 Click Fit 
    450  
    451  
     372If the data to be fit are in multiple files, load each file, then select each file 
     373in the *Data Explorer*, and *Send To Fitting*. If multiple data sets are in one file, 
     374load that file, *Unselect All Data*, select just those data sets to be fitted, and 
     375*Send To Fitting*. Either way, the result should be that for *n* data sets you have 
     3762*n* graphs (*n* of the data and model fit, and *n* of the resulting residuals). But 
     377it may be helpful to minimise the residuals plots for clarity. 
     378 
     379*NB: If you need to use a customized model, you must ensure that model is available* 
     380*first (see* :ref:`Adding_your_own_models` *).* 
     381 
     382Now go to each *FitPage* in turn and: 
     383 
     384  Select the required category and model; 
     385 
     386  Unselect all the model parameters; 
     387 
     388  Enter some starting guesses for the parameters; 
     389 
     390  Enter any parameter limits (recommended); 
     391 
     392  Select which parameters will refine (selecting all is generally a bad idea...); 
     393 
     394When done, select *Constrained or Simultaneous Fit* under *Fitting* in the menu bar. 
     395 
     396In the *Const & Simul Fit* page that appears, select which data sets are to be 
     397simultaneously fitted (this will probably be all of them or you would not have loaded 
     398them in the first place!). 
     399 
     400To tie parameters between the data sets with constraints, check the 'yes' radio button 
     401next to *Add Constraint?* in the *Fit Constraints* box. 
     402 
     403*NB: You can only constrain parameters that are set to refine.* 
     404 
     405When ready, click the *Fit* button on the *Const & Simul Fit* page, NOT the *Fit* 
     406button on the individual *FitPage*'s. 
    452407 
    453408Simultaneous Fits without Constraints 
    454409^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
    455410 
    456 Assuming some FitPages are already set up, check the checkboxes of the  
    457 model_data rows to fit. And click the 'Fit' button. The results will return to  
    458 each FitPages. 
    459  
    460 Note that the chi2/Npts returned is the sum of the chi2/Npts of each fits. If  
    461 one needs the chi2 value only for a page, click the 'Compute' button in the  
    462 FitPage to recalculate. 
     411The results of the model-fitting will be returned to each of the individual 
     412*FitPage*'s. 
     413 
     414Note that the chi2/Npts value returned is the SUM of the chi2/Npts of each fit. To 
     415the chi2/Npts value for a specific *FitPage*, click the *Compute* button at the 
     416bottom of that *FitPage* to recalculate. 
    463417 
    464418Simultaneous Fits with Constraints 
    465419^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
    466420 
    467 Enter constraint in the text control next to *constraint fit*  button.  
    468 Constraint should be of type model1 parameter name = f(model2 parameter name)  
    469 for example, M0.radius=2*M1.radius. Many constraints can be entered for a  
    470 single fit. Each of them should be separated by a newline charater or ";"  
    471 The easy setup can generate many constraint inputs easily when the selected  
    472 two models are the same type. 
    473  
    474 Note that the chi2/Npts returned is the sum of the chi2/Npts of each fits.  
    475 If one needs the chi2 value only for one fit, click the 'Compute' button in  
    476 the FitPage to recalculate. 
     421Use the *Easy Setup* drop-down buttons in the *Const & Simul Fit* page to set 
     422up constraints between *FitPage*'s. 
     423 
     424Constraints will generally be of the form Mi Parameter1 = Mj.Parameter1, however 
     425the text box after the '=' sign can be used to adjust this relationship; for 
     426example Mi Parameter1 = scalar*Mj.Parameter1. A 'free-form' constraint box is 
     427also provided. 
     428 
     429Many constraints can be entered for a single fit. 
     430 
     431The results of the model-fitting will be returned to each of the individual 
     432*FitPage*'s. 
     433 
     434Note that the chi2/Npts value returned is the SUM of the chi2/Npts of each fit. To 
     435the chi2/Npts value for a specific *FitPage*, click the *Compute* button at the 
     436bottom of that *FitPage* to recalculate. 
    477437 
    478438.. ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ 
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