An MxMatrix is an object which contains five separate R matrices and five metainformation slots: a type, the number of rows and columns; the labels for each row and column (in R this is called dimnames); and the name by which the matrix is known in its MxModel namespace. The five matrices in the MxMatrix are all of the same order, but of different R storage types. The values matrix holds the starting (or estimated) values and is of type double. The labels matrix is of type character and holds the name of each element of the matrix. Matrix elements that have the same name are constrained to be equal to one another. The free matrix is of type logical and if an element is TRUE, then that element is considered to be a free parameter during estimation. The lbound and ubound matrices are of type double and contain lower and upper bounds for the free parameters.
