MxMatrix-class {OpenMx}R Documentation

MxMatrix Class

Description

MxMatrix is an S4 class. An MxMatrix object is a named entity. New instances of this class can be created using the function mxMatrix. MxMatrix objects may be used as arguments in other functions from the OpenMx library, including mxAlgebra, mxConstraint, and mxModel.

Details

The MxMatrix class has the following slots:

name - the name of the object
free - the free matrix
values - the values matrix
labels - the labels matrix

The 'name' slot is the name of the MxMatrix object. Use of MxMatrix objects in an mxAlgebra or mxConstraint function requires reference by name.

The 'free' slot takes a matrix which describes the location of free and fixed parameters. A variable is a free parameter if-and-only-if the corresponding value in the 'free' matrix is 'TRUE'. Free parameters are elements of an MxMatrix object whose values may be changed by an objective function when that MxMatrix object is included in an MxModel object and evaluated using the mxRun function.

The 'values' slot takes a matrix of numeric values. If an element is specified as a fixed parameter in the 'free' matrix, then the element in the 'values' matrix is treated as a constant value and cannot be altered or updated by an objective function when included in an mxRun function. If an element is specified as a free parameter in the 'free' matrix, the element in the 'value' matrix is considered a starting value and can be changed by an objective function when included in an mxRun function.

The 'labels' slot takes a matrix which describes the labels of free and fixed parameters. Fixed parameters with identical labels must have identical values. Free parameters with identical labels impose an equality constraint. The same label cannot be applied to a free parameter and a fixed parameter. A free parameter with the label 'NA' implies a unique free parameter, that cannot be constrained to equal any other free parameter.

References

The OpenMx User's guide can be found at http://openmx.psyc.virginia.edu/documentation.

See Also

mxMatrix for creating MxMatrix objects. More information about the OpenMx package may be found here.


[Package OpenMx version 2.0.0-3948 Index]