ENIGMA: maximum-entropy method program package for huge systems

2002/03/22 by Hiroshi Tanaka, Masaki Takata, Eiji Nishibori +3 · 4 citations
Materials Science · Physics and Astronomy · Earth and Planetary Sciences · #Machine Learning in Materials Science #Nuclear Physics and Applications #High-pressure geophysics and materials

paper · doi:10.1107/s002188980200050x

Abstract

ENIGMA ( Electron and Nuclear Image Generator by Max-ent Analysis ) is a program package to evaluate three-dimensional electron and nuclear density from X-ray and neutron diffraction data by using the maximum-entropy method (MEM). Compared with the previous program package MEED , ENIGMA saves computing time and frees memory space at the same time by employing parallel data processing. The fast Fourier transformation (FFT) technique is also implemented. As a consequence of these improvements, the MEM analysis by ENIGMA becomes applicable to huge systems, such as proteins and polymers, when the phased structure factors are provided. The package is transferable to a wide variety of parallel computers, because it is written in Fortran 90 and a standard message-passing interface (MPI).

Cited by

• Observation of gas molecules adsorbed in the nanochannels of porous coordination polymers by the in situ synchrotron powder diffraction experiment and the MEM/Rietveld charge density analysis
• Electron charge distribution of CaAl2−xZnx: Maximum entropy method combined with Rietveld analysis of high-resolution-synchrotron X-ray powder diffraction data
• Analysis of oxygen vacancy in Co-doped ZnO using the electron density distribution obtained using MEM. [europepmc]
• Formation of ferromagnetic Co-H-Co complex and spin-polarized conduction band in Co-doped ZnO. [europepmc]

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