Package: mGSFPCA
Title: Estimate Functional Principal Components from Sparse Data
Version: 0.2.2
Authors@R: 
    c(person("Uche", "Mbaka", , "uche.mbaka@ucd.ie", role = c("aut", "cre"),
           comment = c(ORCID = "0000-0002-1427-6388")), 
      person("Michelle", "Carey", , "michelle.carey@ucd.ie", role = "ctb",
            comment = c(ORCID = "0000-0002-5603-4264"))
      )
Description: Implements functional principal component analysis (FPCA) for
    univariate and multivariate sparse functional data. The package estimates
    eigenfunctions, eigenvalues, and error variance simultaneously via maximum
    likelihood estimation (MLE), using a spline basis representation of the
    eigenfunctions. Orthonormality of the estimated eigenfunctions is enforced
    through a modified Gram-Schmidt (MGS) orthogonalization procedure applied
    iteratively during estimation, avoiding direct optimization over the Stiefel
    manifold and improving numerical stability. The optimal number of basis
    functions and principal components is selected via an Akaike Information
    Criterion (AIC)-type criterion, supporting both a full grid-search strategy
    and a computationally efficient sequential selection approach. Principal
    component scores are estimated by conditional expectation, enabling
    reconstruction of individual trajectories over the entire domain from sparse
    observations. Pointwise confidence intervals for reconstructed trajectories 
    are also provided. Methods are described in Mbaka, Cao and Carey
    (2026) <doi:10.48550/arXiv.2603.18833> and Mbaka and Carey (2026)
    <doi:10.48550/arXiv.2603.19799>.
License: GPL (>= 3)
Encoding: UTF-8
RoxygenNote: 7.3.2
Depends: R (>= 2.10)
LazyData: true
Imports: fda, pracma, Rcpp, Metrics
LinkingTo: Rcpp, RcppEigen
NeedsCompilation: yes
Packaged: 2026-05-05 11:16:36 UTC; fdagroup
Author: Uche Mbaka [aut, cre] (ORCID: <https://orcid.org/0000-0002-1427-6388>),
  Michelle Carey [ctb] (ORCID: <https://orcid.org/0000-0002-5603-4264>)
Maintainer: Uche Mbaka <uche.mbaka@ucd.ie>
Repository: CRAN
Date/Publication: 2026-05-08 14:30:02 UTC
Built: R 4.6.0; x86_64-w64-mingw32; 2026-06-02 04:32:00 UTC; windows
Archs: x64
