retistruct (version 0.6.3)

dE: The deformation energy gradient function

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