Convert lavaan syntax to RAM specification

Converts SEM models to RAM models for OpenMx.

Usage

as_ram(x, ...)

# S3 method for class 'data.frame'
as_ram(x, groups = NULL, data = NULL, threshold_method = "mxThreshold", ...)

Arguments

x

An object for which a method exists, such as a tidy_sem object, or character vector describing the user-specified model using the lavaan model syntax.

...

Parameters passed on to other functions.

groups

Character, either corresponding to the name of a column in data, or else a vector of group names.

data

Optional, a data.frame which is added to the model.

threshold_method

Character, one of c("mxThreshold", "mx_deviances"). Method used to specify thresholds for ordinal indicators. See the mxThreshold function in the OpenMx package, and mx_deviances, respectively.

Value

Returns an mxModel.

Details

For models specified using lavaan syntax, the procedure is as follows:

1. Apply lavaanify to the model. The default arguments to lavaanify correspond to those of the sem function.

2. Apply the method for data.frame to the resulting lavaan parameter table. This uses mxPath for means, regression coefficients, and (co)variances, and the specified threshold_method for thresholds.

3. Apply mxModel to the resulting list of mxPath and mxMatrix elements to create an mxModel using RAM specification.

Examples

as_ram("y ~ x")
#> MxModel 'model' 
#> type : RAM 
#> $matrices : 'A', 'S', 'F', and 'M' 
#> $algebras : NULL 
#> $penalties : NULL 
#> $constraints : NULL 
#> $intervals : NULL 
#> $latentVars : none
#> $manifestVars : 'y' and 'x' 
#> $data : NULL
#> $submodels : NULL 
#> $expectation : MxExpectationRAM 
#> $fitfunction : MxFitFunctionML 
#> $compute : NULL 
#> $independent : FALSE 
#> $options :  
#> $output : FALSE