This function implements the approximation method within the Gaussian copula graphical model to estimate the conditional expectation for the data that not follow Gaussianity assumption (e.g. ordinal, discrete, continuous non-Gaussian, or mixed dataset).
R.approx(y, Z = NULL, Sigma=NULL, rho = NULL, ncores = NULL )
An (\(n \times p\)) matrix or a data.frame
corresponding to the data matrix (\(n\) is the sample size and \(p\) is the number of variables).
It also could be an object of class "simgeno"
.
A (\(n \times p\)) matrix which is a transformation of the data via the Gaussian copula. If Z = NULL
internally calculates an initial value for \(Z\).
The covariance matrix of the latent variable given the data. If Sigma = NULL
the Sigma matrix is calculated internally with a desired penalty term, rho
.
A (non-negative) regularization parameter to calculate Sigma
. rho=0 means no regularization.
If ncores = NULL
, the algorithm internally detects number of available cores and run the calculations in parallel on (available cores - 1). Typical usage is to fix ncores = 1
when \(p\) is small \(( p < 500 )\), and ncores = NULL
when \(p\) is large.
Expectation of covariance matrix( diagonal scaled to 1) of the Gaussian copula graphical model.
New transformation of the data based on given or default Sigma
.
1. Behrouzi, P., and Wit, E. C. (2017c). netgwas: An R Package for Network-Based Genome-Wide Association Studies. arXiv preprint, arXiv:1710.01236. 2. Behrouzi, P., and Wit, E. C. (2017a). Detecting Epistatic Selection with Partially Observed Genotype Data Using Copula Graphical Models. arXiv preprint, arXiv:1710.00894.
# NOT RUN {
D <- simgeno(p = 90, n = 50, k = 3)
R.approx(D$data)
# }
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