dE: The deformation energy gradient function

In retistruct: Retinal Reconstruction Program

Description

The function that computes the gradient of the energy (or error) of the deformation of the mesh from the flat outline to the sphere. This depends on the locations of the points given in spherical coordinates. The function is designed to take these as a vector that is received from the optim function.

Usage

dE(
  p,
  Cu,
  C,
  L,
  B,
  T,
  A,
  R,
  Rset,
  i0,
  phi0,
  lambda0,
  Nphi,
  N,
  alpha = 1,
  x0,
  nu = 1,
  verbose = FALSE
)

Arguments

p	Parameter vector of phi and lambda
Cu	The upper part of the connectivity matrix
C	The connectivity matrix
L	Length of each edge in the flattened outline
B	Connectivity matrix
T	Triangulation in the flattened outline
A	Area of each triangle in the flattened outline
R	Radius of the sphere
Rset	Indices of points on the rim
i0	Index of fixed point on rim
phi0	Latitude at which sphere curtailed
lambda0	Longitude of fixed points
Nphi	Number of free values of phi
N	Number of points in sphere
alpha	Area penalty scaling coefficient
x0	Area penalty cut-off coefficient
nu	Power to which to raise area
verbose	How much information to report

Value

A vector representing the derivative of the energy of this particular configuration with respect to the parameter vector

Author(s)

David Sterratt

retistruct documentation built on April 4, 2020, 5:08 p.m.