Gemmi crystallography

Gemmi has functions to calculate structure factor by direct summationof structure factors from individual atoms

This route is not commonly usedin macromolecular crystallography and it was implemented primarily to checkthe accuracy of FFT-based computations

Therefore, the efficiency was nota priority here

Gemmi supports three reflection file formats: MTZ files – the most popular format in macromolecular crystallography, structure factor mmCIF files – used for data archivingin the Protein Data Bank, and small molecule structure factor CIF files (usually with extension hkl)

Reflection files store Miller indices (hkl) with various associatednumbers

Gemmi is a library, accompanied by a set of programs, developed primarily for use in macromolecular crystallography (MX)

For working with: data on a 3D grid (electron density maps, masks, MRC/CCP4 format) crystallographic symmetry