ecm_fa: Estimates the parameters of study-specific FA models

Description Usage Arguments Value References

View source: R/MSFA_R.R

Description

Maximum likelihood estimation of study-specific FA models parameters via the ECM algorithm, adopting the upper-triangular zero constraint to achieve identification for each loading matrix. Note: the function can also estimate a FA model for a single study, by specifiyng X_s = list(data), where data is the data matrix.

Usage

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ecm_fa(
  X_s,
  tot_s,
  nIt = 50000,
  tol = 10^-7,
  block_lower = TRUE,
  robust = FALSE,
  corr = TRUE,
  mcd = FALSE,
  trace = TRUE,
  traceIT = 1000
)

Arguments

X_s

List of lenght S, corresponding to number of different studies considered. Each element of the list contains a data matrix, with the same number of columns P for all the studies.

tot_s

Number of latent factors for each study. A vector of positive integers of length S.

nIt

Maximum number of iterations for the ECM algorithm. Default is 50000.

tol

Tolerance for declaring convergence of the ECM algorithm. Default is 10^-7.

block_lower

Should the upper-triangular zero constraint be enforced? Default is TRUE (strongly suggested).

robust

If TRUE, robust covariance matrix is used in place of the sample covariance. Default is FALSE.

corr

If TRUE, the analysis will employ the correlation matrix instead of the covariance matrix.

mcd

If TRUE, the robust estimator used for the covariance is the same proposed in Pison et al. (2003), otherwise the default value of the function CovRob of the robust library is employed. Default is FALSE.

trace

If TRUE then trace information is being printed every traceIT iterations of the ECM algorithm.

traceIT

Frequency of tracing information.

Value

A list containing the following components:

Omega_s, Psi_s

the estimated model matrices.

loglik

the value of the log likelihood function at the final estimates.

AIC, BIC

model selection criteria at the estimate.

npar

number of model parameters.

iter

the number of ECM iterations performed.

References

De Vito, R., Bellio, R., Trippa, L. and Parmigiani, G. (2019). Multi-study Factor Analysis. Biometrics, 75, 337-346.

Pison, G., Rousseeuw, P.J., Filzmoser, P. and Croux, C. (2003). Robust factor analysis. Journal Multivariate Analysis, 84, 145-172.


rdevito/MSFA documentation built on March 18, 2020, 2:57 p.m.