title: The anatomy of a comprehensive constrained, restrained refinement program for the modern computing environment - Olex2 dissected.
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.
authors.affiliation: Bruker AXS-SAS, 4 Allée Lorentz, 77447 Marne-la-Vallée cedex 2, France.
authors.forename: Luc J
authors.initials: LJ
authors.lastname: Bourhis
authors.affiliation: OlexSys Ltd, Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, England.
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Dolomanov
authors.affiliation: Diamond Light Source Ltd, Diamond House, Harwell Oxford, Didcot, Oxfordshire, OX11 0DE, England.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Gildea
authors.affiliation: Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, England.
authors.forename: Judith A K
authors.initials: JA
authors.lastname: Howard
authors.affiliation: OlexSys Ltd, Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, England.
authors.forename: Horst
authors.initials: H
authors.lastname: Puschmann
keywords: Olex2; constraints; least squares; refinement; restraints; small molecules