subdirectory ./fit - experimental data for fit (optional)

In order that McPhase can calculate the standard deviation between experimental data and the results of the simulation, some experimental data can be given in the subdirectory ./fit. The filenames and the data-format are the same as the output files of McPhas, e.g. mcphas.fum, mcphas.hkl etc. McPhase looks into the directory ./fit and if it finds any of these files, the standard deviation is increased correspondingly.

What measurement data can be used to calculate a standard deviation ?

mcphas.fum

if given in column 11, 12, 13 in ./fit/mcphas.fum the magnetisation in the $a$, $b$ and $c$ direction is used for calculation of the standard deviation sta. The standard deviation is calculated as ${\rm sta}=\sum_{\rm data points i} ({\mathbf m}_i^{calc}-{\mathbf m}_i^{meas})^2$. All three components of the magnetic moment have to be given and are used.

Note that the measured data has to be given in those (H-T) points which are calculated by mcphas in order to be used by the program to increase sta. It is usually most effective to fit only few data points, because a large set of data points will not improve the quality of the fit and only require a large amount of calculation time.