Many of these methods require that the uncorrected reflection file name.HKL contains SHELX-style direction cosines which are consistent with the unit cell found in the name.INS file. The data processing programs XCAD4 and PROFIT provide a facility to write out such direction cosines for CAD4 and Siemens P4 data. The REFDELF programs require that a preliminary model has been obtained and DIFABS-CAD4, XABS2 and SHELXA need a CIF style structure factor file (name.FCF). The only programs which do not need any geometrical information about the crystal orientation or the reflection data are XABS2 and CAMEL JOCKEY.
The corrections are grouped into three kinds, according to the methodology: