GAPD : a GPU‐accelerated atom‐based polychromatic diffraction simulation code

GAPD , a graphics‐processing‐unit (GPU)‐accelerated atom‐based polychromatic diffraction simulation code for direct, kinematics‐based, simulations of X‐ray/electron diffraction of large‐scale atomic systems with mono‐/polychromatic beams and arbitrary plane detector geometries, is presented. This code implements GPU parallel computation via both real‐ and reciprocal‐space decompositions. With GAPD , direct simulations are performed of the reciprocal lattice node of ultralarge systems (∼5 billion atoms) and diffraction patterns of single‐crystal and polycrystalline configurations with mono‐ and polychromatic X‐ray beams (including synchrotron undulator sources), and validation, benchmark and application cases are presented.