umxSetParameters: Change or fix parameters (e.g. their values, labels, bounds,...

In tbates/umx: Structural Equation Modeling and Twin Modeling in R

Change or fix parameters (e.g. their values, labels, bounds, ..) in a model.

Description

umxSetParameters is used to alter values, and other parameter properties in an OpenMx::mxModel(). A common use is setting new values and changing parameters from free to false. Note: If you just want to modify and re-run a model, you probably want umxModify().

Usage

umxSetParameters(
  model,
  labels,
  free = NULL,
  values = NULL,
  newlabels = NULL,
  lbound = NULL,
  ubound = NULL,
  indep = FALSE,
  strict = TRUE,
  name = NULL,
  regex = FALSE,
  test = FALSE
)

Arguments

model	an OpenMx::mxModel() to set parameters in.
labels	= labels to find
free	= new value for free
values	= new values
newlabels	= newlabels
lbound	= value for lbound
ubound	= value for ubound
indep	= whether to look in indep models
strict	whether to complain if labels not found
name	= new name for the returned model
regex	patterns to match for labels (or if TRUE, use labels as regular expressions)
test	Just show what you would do? (defaults to FALSE)

Details

Using umxSetParameters, you use ⁠labels=⁠ to select the parameters you want to update. You can set their free/fixed state with ⁠free=⁠, and set new values with ⁠values = ⁠. Likewise for bounds.

umxSetParameters supports pattern matching (regular expressions) to select labels. Set ⁠regex=⁠ to a regular expression matching the labels you want to select. e.g. "G_to_.*" would match "G_to_anything".

Details Internally, umxSetParameters is equivalent to a call to omxSetParameters where you have the ability to generate a pattern-based label list, and, because this can create duplicate labels, we also call OpenMx::omxAssignFirstParameters() to equate the start values for parameters which now have identical labels.

Value

• OpenMx::mxModel()

References

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

See Also

• umxModify(), xmuLabel()

Other Model Summary and Comparison: umx, umxCompare(), umxEquate(), umxMI(), umxReduce(), umxSummary()

Examples

## Not run: 
require(umx)
data(demoOneFactor)
latents  = c("G")
manifests = names(demoOneFactor)
m1 = umxRAM("One Factor", data = mxData(demoOneFactor[1:80,], type = "raw"),
	umxPath(from = latents, to = manifests),
	umxPath(v.m. = manifests),
	umxPath(v1m0 = latents)
)
parameters(m1)
# Match all labels
umxSetParameters(m1, regex = "^", newlabels= "m1_", test = TRUE)

# Change path to x1 to x2, equating these two paths
m2 = umxSetParameters(m1, "G_to_x1", newlabels= "G_to_x2", test = FALSE)
m2 = umxRun(m2) # umxSetParameters does not re-run he model, so make sure you do!
parameters(m2)


## End(Not run)

tbates/umx documentation built on Dec. 14, 2024, 11:28 a.m.