omxAssignFirstParameters: Assign First Available Values to Model Parameters

In OpenMx: Extended Structural Equation Modelling

Assign First Available Values to Model Parameters

Description

Sometimes, in your model, you may have a free parameter with two or more different starting values, lower bounds, and/or upper bounds. OpenMx will not run a model until all instances of a free parameter have the same starting value, lower bound, and upper bound. It is often sufficient to arbitrarily select one of those starting values for optimization; bounds may also be selected arbitrarily, but users should do so with more caution.

This function accomplishes that task of assigning valid starting values and bounds to the free parameters of a model. It selects an arbitrary current value (the "first" value it finds, where "first" is not defined) for each free parameter and uses that value for all instances of that parameter in the model.

Usage

omxAssignFirstParameters(model, indep = FALSE)

Arguments

model	a MxModel object.
indep	assign parameters to independent submodels.

See Also

omxGetParameters, omxSetParameters

Examples

A     <- mxMatrix('Full', 3, 3, values = c(1:9), labels = c('a','b', NA),
                  free = TRUE, name = 'A')
model <- mxModel(model=A, name = 'model')
model <- omxAssignFirstParameters(model)

# Note: All cells with the same label now have the same start value.
# Note also that NAs are untouched.

model$matrices$A

# $labels
#      [,1] [,2] [,3]
# [1,] "a"  "a"  "a" 
# [2,] "b"  "b"  "b" 
# [3,] NA   NA   NA  
# 
# $values
#      [,1] [,2] [,3]
# [1,]    1    1    1
# [2,]    2    2    2
# [3,]    3    6    9

OpenMx documentation built on June 8, 2025, 9:33 p.m.