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PubMed · 15213383

Simple algorithm for a maximum-likelihood SAD function.

Airlie J McCoy·Laurent C Storoni·Randy J Read
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Abstract

Recently, the multivariate complex normal distribution has been used to develop a maximum-likelihood probability function for single-wavelength anomalous diffraction phasing and refinement of heavy-atom parameters [Pannu & Read (2004), Acta Cryst. D60, 22-27]. The function accounts explicitly for the correlations between the observed and calculated Friedel mates and their errors. However, the method of derivation of the equation described by Pannu & Read (2004) leads to a complicated likelihood expression that suffers from a number of algorithmic limitations. Here, an alternative derivation of the P(SAD) function is described that leads to simplified algorithmic requirements and that allows an intuitive understanding of the expression.

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AlgorithmsDNA, Z-FormLikelihood FunctionsJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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Airlie J McCoy, Laurent C Storoni, Randy J Read. 2004-06-22. Simple algorithm for a maximum-likelihood SAD function.. https://doi.org/10.1107/s0907444904009990

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