Emrys::UncertainInput Concept Reference

An argument of transform() that is uncertain: something with a mean, a space, and either a covariance, whose lower triangle covarianceLower() gives, or a lower-triangular root \( S \) of it, \( S S^T = \Sigma \), which root() gives. More...

#include <EmrysFilter/Models/Linearization.h>

Concept definition

template<typename T>
concept UncertainInput = requires(T const & input) {
    typename T::Scalar;
    typename T::SpaceType;
    input.mean();
    input.space();
    input.valueDimension();
    input.differenceDimension();
} && (requires(T const & input) { input.covarianceLower(); } || requires(T const & input) { input.root(); })

Detailed Description

An argument of transform() that is uncertain: something with a mean, a space, and either a covariance, whose lower triangle covarianceLower() gives, or a lower-triangular root \( S \) of it, \( S S^T = \Sigma \), which root() gives.

A GaussianParams, a Gaussian, and a GaussianMarginal give the covariance; a SqrtGaussianParams and a SqrtGaussian give the root, which the sigma-point methods spread their points by as it is (Transform::root()), and whose covariance is formed only where a method needs it. The information forms are not inputs, since their mean fails where the precision is singular: convert one with toSqrt() or toGaussian(), which report that failure.