It is assumed that experimental diffraction data is available and has been converted into a format suitable for CNS (see the other tutorials). Cross validation will be used to monitor the subsequent refinement of the model and also to reduce bias in map calculations. The cross validation information is added to the reflection file using the CNS task file make_cv.inp.
cns_solve < make_cv.inp > make_cv.out [20 seconds]
A new reflection array is created, by default the name TEST is used. The array contains integer numbers, by default 1 signifies that the reflection will be used for cross-validation (i.e. excluded from refinement).