## 3 Results
### Fitting Options  
The fitting offers eight different fitting algorithms under the _Algorithms_ tab, as visible in Figure 9a, where one or more options can be chosen for fitting. The other tabs that appear after the _Fit_ button (Figure 4) is clicked contain the same parameters as the _Vis guess_ option. It is important to check the limits for each parameter, which can be set in an absolute or relative fashion. They limit the fitting of the particular parameter. If the limits are too broad, it is more probable that the fitting will go in the wrong direction. On the other hand, if they are too narrow, then the fit will possibly not be able to reach the correct value. However, for most of the parameters, it is possible to estimate the limits correctly. Some of them can be estimated from the GISAXS map, such as the multilayer period, or lateral separation of the NPs (parameter \(|\,a_{1}|\)). The background can also be easily estimated. The width of the Bragg spots related to the 3D lattice formation can be used for the estimation of the disorder parameters. The _Vis Guess_ option is very helpful for this. Setting the limits is very important because the model contains numerous parameters, and many local minima exist in the fitting function. Therefore, if the initial parameters and the limits are not set correctly, it is possible that the fit finishes in some local minima. When the fitting process is started, the software updates the user about the progress of the fit via the status text window, as visible in Figure 9b. We can stop any of the started fitting algorithms at any time using the  
Figure 8: (**a**) Tab _Nanoparticle Shape Params_ and its parameters. (**b**) Some of NP shapes currently available in the software: spheroid defined by lateral (in \(x\)-\(y\) plane) and vertical (\(z\) direction) radii \(R_{\rm x}\) and \(R_{\rm z}\), respectively. Option _Ellipsoidal_ has the additional radius \(R_{\rm y}\) in the \(y\) direction; tilted ellipsoid with the tilt along basis vector \(\mathbf{a}_{3}\). (**c**) Core-shell spheroid with the core and shell radii \(R_{\rm core}\) and \(R_{\rm shell}\), respectively, and the shift of the shell origin \(d\). The spheroidal shape is defined by factor \(F\), so that the actual vertical radii are the product of \(R_{\rm core}\) and \(R_{\rm shell}\) and factor \(F\). options _stop_ or _kill_. Some optimization algorithms can be benignly stopped, and can report the best-found values before they were ended, while others can only be killed, and cannot report any data. Finally, when the fitting procedure is finished, a new tab (Figure 9c) pops up. This tab shows the simulated GISAXS map and the parameters of the fit, along with the line profiles showing the intensity distribution at the chosen cross section. Finally, the software offers the _Batch fit_ option. Sometimes, fitting can be a time-consuming operation, especially if the number of parameters is large or when user wants to check many variations. In these cases, it is possible to generate an arbitrary number of initial parameter sets (\"batch items\"), store them in the database, and then launch the batch fitting process, for instance, overnight. Figure 10a shows the dialog for setting the parameters for batch fit. Multiple initial values of each parameter, along with lower and upper limits, can be set by typing in comma delimited values (e.g., \"1, 3, 8\"), or by using  
Figure 9: Tabs related to the fitting of the 2D GISAXS map. (**a**) The window with fitting parameters, including the same parameters as in Vis _guess_ option and an additional _Algorithms_ tab that enables the choice of the fitting algorithms. (**b**) Window that appears after starting of the fit, showing its progress. After the fitting is finished, the parameters are shown in the window at the bottom. (**c**) Results of the fitting process, including the original and simulated GISAXS map using the best-fit parameters, along with the line profiles at the right.