=== Requested File Matrix ===

The handling of the optical constants is a very challenging task. Different modes and algorithm requires different files. 

{{:documentation:requested_file_matrix2.png|}}


For more information go to the [[documentation:file_formats|File Formats]] section. 


=== Cacheing and automatic updating of the optical constants ===

The energy scan calculation requires for each energy their specific optical constants. Therefore this function demands for the correct optical constants files.
This is not necessary for const-energy (reflectivity) scans. This feature can be forced in the "Optical Constants Database" tab by activating automatic updating.