Standardize a RAM Model

You're right. I did that as a work-around to mxSummary, which returned the row names as numeric 1:4 and column names as characters 1:4. I now realize that won't work if someone actually specifies dimnames for their A and S matrices. I added a patch that gives the invSDs default names of the numbers 1:length(invSDs) as characters, so that invSDs[1] and invSDs["1"] both work. However, if there are dimnames on the columns of the A matrix, those are populated instead. I'm choosing not to check whether the dimnames of A and the dimnames of S are identical, because they're usually either NULL or autopopulated to be equal through type="RAM". One would have to manually set A and S to have different dimnames.

I might as well describe the function a little better. The primary argument is an existing model to be standardized. If it is type="RAM" or uses the mxRAMObjective, you don't have to do anything else. If you don't use the RAM objective (say, you use an algebra to to the RAM matrices), you have to supply the names (as character strings) of the A and S matrices. The output (varied by the argument 'return') is either an mxSummary-style list of standardized parameters and standard errors (return="parameters"), the standardized matrices (return="matrices") or a model with the standardized A and S matrices populated (return="model").

The last option also returns a standardized M matrix, which is all zeros by definition, whereas the parameters and matrices options don't return the M matrices or their free parameters. It should be noted that return="model" only changes the model matrices; no changes are made to the 'output' slot of a returned model, summary(standardizeRAM(model)) will look exactly like summary(model). If you want a standardized parameter list a la summary, use standardizeRAM(model).

The correct syntax is:

standardizeRAM(Fit4238, Amat="A", Smat="S", Mmat="M")