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. 2015 Jan;71(Pt 1):59-75.
doi: 10.1107/S2053273314022207. Epub 2015 Jan 1.

The anatomy of a comprehensive constrained, restrained refinement program for the modern computing environment - Olex2 dissected

Luc J Bourhis  1 , Oleg V Dolomanov  2 , Richard J Gildea  3 , Judith A K Howard  4 , Horst Puschmann  2
Affiliations

The anatomy of a comprehensive constrained, restrained refinement program for the modern computing environment - Olex2 dissected

Luc J Bourhis et al. Acta Crystallogr A Found Adv. 2015 Jan.

Abstract

This paper describes the mathematical basis for olex2.refine, the new refinement engine which is integrated within the Olex2 program. Precise and clear equations are provided for every computation performed by this engine, including structure factors and their derivatives, constraints, restraints and twinning; a general overview is also given of the different components of the engine and their relation to each other. A framework for adding multiple general constraints with dependencies on common physical parameters is described. Several new restraints on atomic displacement parameters are also presented.

Keywords: Olex2; constraints; least squares; refinement; restraints; small molecules.

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Figures

Figure 1
Figure 1
A high-level depiction of the software modules involved in olex2.refine: an arrow is drawn from each component pointing towards another component it uses.
Figure 2
Figure 2
Example of a dependency graph for the chain of reparametrization discussed in §3. Only the part for hydrogen atom H0 is shown.
See this image and copyright information in PMC

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