Data reduction: d*TREK

Diffraction image data processing has been an area where device independence has been beneficial for many decades as new goniometers, new detectors, new image formats and new beamlines are brought into
use. An outline of how to create a device-independent program will be given with the d*TREK package as an example. We will describe how to connect a new goniometer and a new detector with a new image
format to the d*TREK package.

A second part will concentrate on statistics derived from the resultant estimated intensities and standard uncertainties (sigmas). Mathematical procedures to reduce the observed Bragg reflections to
a unique set of reflections will be presented. Rmerge, Rmeas, Ras, reduced chi-squared and other terms will be used to judge the quality of the diffraction experiment.