S2FunHarmonic.interpolate edit page

Interpolate an S2FunHarmonic by given function values at given points on the sphere.

Let \(M\) spherical points \(v_i\) and corresponding function values \(y_i\) be given. We compute the S2FunHarmonic \(f\) of an specific bandwidth which minimizes the least squares problem

\[\sum_{i=1}^M|f(v_i)-y_i|^2.\]

Syntax

sF = S2FunHarmonic.interpolate(nodes, val)
sF = S2FunHarmonic.interpolate(nodes, val, 'bandwidth', bandwidth, 'tol', TOL, 'maxit', MAXIT, 'weights', W)
sF = S2FunHarmonic.interpolate(nodes,val,'regularization',0) % no regularization
sF = S2FunHarmonic.interpolate(nodes,val,'regularization',1e-4,'SobolevIndex',2)
[sF,lsqrParameters] = S2FunHarmonic.interpolate(___)

Input

nodes vector3d (grid on sphere)
val function values on the grid (may be multidimensional)

Options

bandwidth maximum degree of the spherical harmonics used to approximate the function
tol tolerance for lsqr
maxit maximum number of iterations for lsqr
weights weight w_n for the node nodes (default: Voronoi weights)

See also

vector3d.interp S2VectorFieldHarmonic.interpolate

Citing this page. This page is part of the documentation of MTEX, a free and open source MATLAB toolbox for analyzing and modeling crystallographic textures. It was written by The MTEX Developers and is published at https://mtex-toolbox.github.io/S2FunHarmonic.interpolate.html. If you use MTEX, or reuse text or figures from this page, in your research, please cite

F. Bachmann, R. Hielscher, H. Schaeben: Texture Analysis with MTEX - Free and Open Source Software Toolbox, Solid State Phenomena 160 (2010), 63-68. 10.4028/www.scientific.net/SSP.160.63

BibTeX
@article{bachmann2010mtex,
  author  = {F. Bachmann and R. Hielscher and H. Schaeben},
  title   = {Texture Analysis with MTEX - Free and Open Source Software Toolbox},
  journal = {Solid State Phenomena},
  volume  = {160},
  pages   = {63-68},
  year    = {2010},
  doi     = {10.4028/www.scientific.net/SSP.160.63},
  url     = {https://doi.org/10.4028/www.scientific.net/SSP.160.63}
}

Other papers describing specific MTEX methods are listed under Publications — please cite the one that best fits your application. The MTEX source code is licensed under the GNU General Public License v2.0; the text and figures of this documentation are licensed under CC BY 4.0, which permits reuse — including by automated systems — provided The MTEX Developers and this page are credited.