clipper::ResolutionFn_nonlinear Class Reference

2nd order resolution function evaluator More...

#include <resol_fn.h>

Inheritance diagram for clipper::ResolutionFn_nonlinear:

List of all members.

Public Member Functions
	ResolutionFn_nonlinear (const HKL_info &hkl_info, const BasisFn_base &basisfn, const TargetFn_base &targetfn, const std::vector< ftype > &params, const ftype damp=0.0, const bool debug=false)
	constructor: need reflections, basis fn and target fn.

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Detailed Description

2nd order resolution function evaluator

This is an automatic evaluator for arbitrary functions of HKL, most commonly used for evaluating a function of resolution (such a mean F^2 or sigmaa), although more general tasks including local scaling of reflections and anisotropic functions can also be handled. This form is for target functions which approach zero quadratically, e.g. least-squares targets.

Note:

This version implements a minimiser which uses both Newton-Raphson and gradient steps depending on the situation. It can be used for non-quadratic targets or non-linear basis functions.

To evaluate a resolution function, this class must be provided with two objects:

• The basis function (and gradients), which describes the value of the function for any reflection given a set of paramters.
• The target function (and derivatives), which is used to determine the values of the basis function parameters.

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Constructor & Destructor Documentation

clipper::ResolutionFn_nonlinear::ResolutionFn_nonlinear	(	const HKL_info &	hkl_info,
		const BasisFn_base &	basisfn,
		const TargetFn_base &	targetfn,
		const std::vector< ftype > &	params,
		const ftype	damp = 0.0,
		const bool	debug = false
	)

constructor: need reflections, basis fn and target fn.

The constructor performs the full minimisation calculation.

Parameters:

hkl_info	HKL_info object which provides the reflection list.
basisfn	The basis function used to describe the desired property.
targetfn	The target function to be minimised.
damp_	If > 0.0, shifts are fdamped during early cycles to help convergence with difficult bases/target conbinations

References clipper::ResolutionFn::basisfn_, clipper::ResolutionFn::calc_derivs(), clipper::HKL_info::cell(), clipper::ResolutionFn::cell_, clipper::HKL_class::epsilonc(), clipper::ResolutionFn::f(), clipper::HKL_info::first(), clipper::HKL_info::HKL_reference_index::hkl_class(), clipper::ResolutionFn::hkl_info_, clipper::Util::is_nan(), clipper::HKL_info::HKL_reference_index::last(), clipper::HKL_info::HKL_reference_index::next(), clipper::BasisFn_base::num_params(), clipper::ResolutionFn::params(), clipper::ResolutionFn::params_, clipper::TargetFn_base::rderiv(), clipper::Matrix< T >::solve(), and clipper::ResolutionFn::targetfn_.

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The documentation for this class was generated from the following files:

• resol_fn.h
• resol_fn.cpp