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MLMF : least‐squares approximation of likelihood‐based refinement criteria
Author(s) -
Afonine Pavel,
Lunin Vladimir Y.,
Urzhumtsev Alexandre
Publication year - 2003
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889802021738
Subject(s) - quadratic equation , least squares function approximation , maximum likelihood , mathematics , value (mathematics) , magnitude (astronomy) , statistics , algorithm , physics , geometry , astronomy , estimator
A quadratic approximation of the maximum‐likelihood criterion is defined by a target value for every calculated structure‐factor magnitude and the corresponding weight. These values can be estimated using the experimental structure‐factor magnitudes and general information about the model imperfection. The program MLMF provides a user with these weights and target values. The obtained quadratic approximation allows one to carry out a kind of maximum‐likelihood refinement by means of any least‐squares refinement suite.