# ---------------------------------------------------------------------
# Program: OneFactorCov-OpenMx100221.R
#  Author: Steven M. Boker
#    Date: Sun Feb 21 13:39:29 EST 2010
#
# This program fits a covariance single factor model to the 
#     factorExample1.csv simulated data.
#
#
# ---------------------------------------------------------------------
# Revision History
#    -- Sun Feb 21 13:39:32 EST 2010
#      Created OneFactorCov-OpenMx100221.R.
#
# ---------------------------------------------------------------------

# ----------------------------------
# Read libraries and set options.

options(width=80)

require(psych)
require(OpenMx)

# ----------------------------------
# Read the data and print descriptive statistics.

factorExample1 <- read.csv("factorExample1.csv")

describe(factorExample1)

# ----------------------------------
# Build an OpenMx single factor covariance model with fixed variance

indicators <- names(factorExample1)
latents <- c("F1")
loadingLabels <- paste("b_", indicators, sep="")
uniqueLabels <- paste("U_", indicators, sep="")
meanLabels <- paste("M_", indicators, sep="")
factorVarLabels <- paste("Var_", latents, sep="")

oneFactorCov1 <- mxModel("Single Factor Covariance Model with Fixed Variance",
    type="RAM",
    manifestVars=indicators,
    latentVars=latents,
    mxPath(from=latents, to=indicators, 
           arrows=1, all=TRUE, 
           free=TRUE, values=.2, 
           labels=loadingLabels),
    mxPath(from=indicators, 
           arrows=2, 
           free=TRUE, values=.8, 
           labels=uniqueLabels),
    mxPath(from=latents,
           arrows=2, 
           free=FALSE, values=1, 
           labels=factorVarLabels),
    mxData(observed=cov(factorExample1), type="cov", numObs=500)
    )

oneFactorCov1Out <- mxRun(oneFactorCov1)

summary(oneFactorCov1Out)


# ----------------------------------
# Build an OpenMx single factor covariance model with fixed loading


oneFactorCov2 <- mxModel("Single Factor Covariance Model with Fixed Loading",
    type="RAM",
    manifestVars=indicators,
    latentVars=latents,
    mxPath(from=latents, to=indicators, 
           arrows=1, all=TRUE,
           free=TRUE, values=.2, 
           labels=loadingLabels),
    mxPath(from=indicators, 
           arrows=2, 
           free=TRUE, values=.8, 
           labels=uniqueLabels),
    mxPath(from=latents,
           arrows=2,
           free=TRUE, values=1, 
           labels=factorVarLabels),
    mxPath(from=latents, to=c("x1"),
           arrows=1, 
           free=FALSE, values=1),
    mxData(observed=cov(factorExample1), type="cov", numObs=500)
    )

oneFactorCov2Out <- mxRun(oneFactorCov2)

summary(oneFactorCov2Out)