Calculate linear combinations of orthonormal cosine basis functions on two- or three-dimensional domains
Given scores (coefficients), these functions calculate a linear combination of two- or three-dimensional cosine tensor basis functions on two- or three-dimensional domains using the C-library fftw3
(see http://www.fftw.org/).
dctFunction2D(scores, argvals, parallel = FALSE) dctFunction3D(scores, argvals, parallel = FALSE)
scores: A sparse matrix of dimension N x L, representing the L scores (coefficients), where N is the number of observations.argvals: A list containing two or three numeric vectors, corresponding to the domain grid (x and y values for two-dimensional domains; x,y and z values fro three-dimensional domains.)parallel: Logical. If TRUE, the coefficients for the basis functions are calculated in parallel. The implementation is based on the foreach function and requires a parallel backend that must be registered before; see foreach for details. Defaults to FALSE.An object of class funData with N observations on the two- or threedimensional domain specified by argvals, corresponding to the linear combination of orthonormal cosine basis functions.
If the C-library fftw3 is not available when the package MFPCA is installed, the functions are disabled an will throw an error. For full functionality install the C-library fftw3 from http://www.fftw.org/ and reinstall MFPCA. This function has not been tested with ATLAS/MKL/OpenBLAS.
univExpansion, idct2D, idct3D, dctBasis2D, dctBasis3D