Pirate - unsupported CCP4 module.

pirate performs statistical phase improvement by classifying the electron density map by sparseness/denseness and order/disorder, with the aim of obtaining superior results to conventional solvent mask based methods without requiring knowledge of the solvent content.

The target distributions are generated by a simulation calculation using a known reference structure for which calculated phases are available. The success of the method is dependent on the features of the reference structure matching those of the unsolved, "work" structure. For the common case of a protein of mostly equal atoms (i.e. not a metalloprotein), a standard set of reference structures can be tested, and the one with the best Free residuals used for a full phasing calculation.