• converts reflection data files as obtained from xds or xscale into various formats required by software packages for crystal structure determination like CCP4, CNS (X-PLOR), or SHELX,
• uses a Bayesian approach to statistical inference for estimating structure factor moduli from the reflection intensities (French and Wilson, 1978),
• can inherit test-reflections previously used for the calculation of the free R-factor,
• can select new test-reflections that are outside the resolution range covered by the inherited test-reflections - a feature used if new data at higher resolution become available that should be included in the structure refinement process.

The program uses two files with a fixed name.

XDSCONV.INP

contains the input parameters (see section Input Parameters) you have to provide to run the program. This file is mandatory and must reside in the current directory from which XDSCONV is called.

XDSCONV.LP

is generated by XDSCONV and reports the results and diagnostics from running the program.

Example for XDSCONV.INP for conversion to CNS format

Assume that three data sets, named fae-ip.ahkl, fae-pk.ahkl, and fae-rm.ahkl (see Example 1 for XSCALE.INP), are available from a selenomethionyl protein crystal at different wavelengths and that you want to carry out the subsequent structure analysis by the CNS package.
For conversion to CNS format you make a separate run of XDSCONV for each of the three XSCALE files. The input parameter values for XDSCONV.INP are shown below for the conversion fae-ip.ahkl --> fae-ip.cv . Only the first two lines specifying input and output files are mandatory. By default, all reflections are accepted from the input file, test reflections are not generated, and remaining parameters needed are taken from the header of the input file.

OUTPUT_FILE=fae-ip.cv  CNS
INPUT_FILE=fae-ip.ahkl      !format is XDS_ASCII by default

!<<<<<<<<<<<< Specifications below could have been omitted >>>>>>>>>>>>>>>
 INCLUDE_RESOLUTION_RANGE=20 1.6

 SPACE_GROUP_NUMBER=19
 UNIT_CELL_CONSTANTS=65.46 108.41 113.15   90.000  90.000  90.000
 FRIEDEL'S_LAW=FALSE !TRUE

!This creates new test-reflections from a fraction of the input reflections
!GENERATE_FRACTION_OF_TEST_REFLECTIONS=0.05

In a similar way the other two data sets, fae-pk.cv and fae-rm.cv, are obtained by running XDSCONV after the appropriate changes to XDSCONV.INP have been made. The converted files fae-ip.cv, fae-pk.cv, and fae-rm.cv may then be used directly for input to CNS (CNS input file "merge.inp").