initial_params

Dependent on the specific type of warping functions, this function creates
a vector of initial parameters. For <code>"nonparametric"</code> warpings that
are based on a given spline basis matrix, the initial parameters are defined
s.t. the resulting (inverse) warping function equals a diagonal line.
For <code>"piecewise_linear2"</code> warpings a fixed parameter vector is returned.

A method for performing joint registration and functional principal
component analysis for curves (functional data) that are generated from exponential family distributions. This
mainly implements the algorithms described in 'Wrobel et al. (2019)' <doi:10.1111/biom.12963> and further adapts them to potentially
incomplete curves where (some) curves are not observed from the beginning and/or until the end of the common domain. Curve registration
can be used to better understand patterns in functional data by separating curves into phase and amplitude variability.
This software handles both binary and continuous functional data, and is
especially applicable in accelerometry and wearable technology.

Julia Wrobel

registr

Curve Registration for Exponential Family Functional Data

Alexander Bauer

Erin McDonnell

Fabian Scheipl

Jeff Goldsmith

initial_params function

<dl><dt>warping</dt>
<dd>If <code>nonparametric</code> (default), inverse warping functions are estimated nonparametrically. 
If <code>piecewise_linear2</code> they follow a piecewise linear function with 2 knots.</dd>
<dt>K</dt>
<dd>Spline basis matrix defined over the interval <code>c(t_min, t_max)</code>.</dd>
<dt>t_vec</dt>
<dd>Vector of the observed and potentially irregular time grid.</dd></dl>

Arguments

Create initial parameters for (inverse) warping functions — initial_params

<dl>

<dt>warping</dt>
<dd>If <code>nonparametric</code> (default), inverse warping functions are estimated nonparametrically. 
If <code>piecewise_linear2</code> they follow a piecewise linear function with 2 knots.</dd>


<dt>K</dt>
<dd>Spline basis matrix defined over the interval <code>c(t_min, t_max)</code>.</dd>


<dt>t_vec</dt>
<dd>Vector of the observed and potentially irregular time grid.</dd>

</dl>

initial_params: Create initial parameters for (inverse) warping functions

Description

Usage

Arguments