Emrys::UnscentedRule Concept Reference

A rule for the scaled unscented transform's parameters by the number of coordinates it spreads its points over: a method that places Unscented's \( 2L + 1 \) points with Unscented's weights, at the \( \alpha \), \( \beta \), and \( \kappa \) it gives for each \( L \). More...

#include <EmrysFilter/Models/Methods.h>

Concept definition

template<typename T>
concept UnscentedRule = requires(Eigen::Index n) {
    { T::template params<double>(n) } -> std::same_as<UnscentedParams<double>>;
}

Detailed Description

A rule for the scaled unscented transform's parameters by the number of coordinates it spreads its points over: a method that places Unscented's \( 2L + 1 \) points with Unscented's weights, at the \( \alpha \), \( \beta \), and \( \kappa \) it gives for each \( L \).

Unscented and FourthMomentUnscented are the library's. One of the user's own is any type with the static member below, with nothing of the library's specialized, and is then a TransformMethod: a measurement's method and a filter's prediction method, which spreads its points over the coordinates a model's affineIn() does not name (decisions.md [user-extension-points], [affine-coordinates]). usage.md, "Choosing the unscented parameters by the dimension", writes one.

• template <typename Scalar> static constexpr UnscentedParams<Scalar> params(Eigen::Index n): the parameters over \( n > 0 \) coordinates, computed in Scalar, so that a float filter computes no double [embedded-builds]. It is a constant expression for a constant n, so that the compiler computes the weights of a fixed-size input in float or double, and there it must give \( \alpha^2 (n + \kappa) > 0 \) or the transform fails to compile; elsewhere the transform asserts it.

Over no coordinates the transform is the mean alone and calls nothing. A type meets this concept or PointSet, not both.