umx (version 4.0.0)

umxValues: umxValues: Set values in RAM model, matrix, or path

Description

For models to be estimated, it is essential that path values start at credible values. umxValues takes on that task for you. umxValues can set start values for the free parameters in both RAM and Matrix mxModel()s. It can also take an mxMatrix as input. It tries to be smart in guessing starts from the values in your data and the model type.

Usage

umxValues(obj = NA, sd = NA, n = 1, onlyTouchZeros = FALSE)

Arguments

obj

The RAM or matrix mxModel(), or mxMatrix() that you want to set start values for.

sd

Optional Standard Deviation for start values

n

Optional Mean for start values

onlyTouchZeros

Don't alter parameters that appear to have already been started (useful for speeding umxModify())

Value

• mxModel() with updated start values

Details

note: If you give umxValues a numeric input, it will use obj as the mean, and return a list of length n, with sd = sd.

References

• https://www.github.com/tbates/umx, https://tbates.github.io

See Also

• Core functions:

Other Advanced Model Building Functions: umxJiggle(), umxLabel(), umxThresholdMatrix(), umx

Examples

# NOT RUN {
require(umx)
data(demoOneFactor)
latents = c("G")
manifests = names(demoOneFactor)

# ====================================================================
# = Make an OpenMx model (which will lack start values and labels..) =
# ====================================================================
m1 = mxModel("One Factor", type = "RAM", 
	manifestVars = manifests, latentVars = latents, 
	mxPath(from = latents  , to = manifests),
	mxPath(from = manifests, arrows = 2),
	mxPath(from = latents  , arrows = 2, free = FALSE, values = 1.0),
	mxData(cov(demoOneFactor), type = "cov", numObs=500)
)
mxEval(S, m1) # default variances are jiggled away from near-zero
# Add start values to the model
m1 = umxValues(m1)
mxEval(S, m1) # plausible variances
umx_print(mxEval(S,m1), 3, zero.print = ".") # plausible variances
umxValues(14, sd = 1, n = 10) # Return vector of length 10, with mean 14 and sd 1
# }