OpenMx Developer Forums

For discussion about mxAlgebra()

http://openmx.psyc.virginia.edu/docs/OpenMx/latest/Introduction.html#simple-openmx-script

Says "PS a lower triangular matrix doesn’t exist yet so we specify it explicitly"

scripts using the newer types amongst ‘Diag’, ‘Full’, ‘Iden’, ‘Lower’, ‘Sdiag’, ‘Stand’, ‘Symm’, ‘Unit’, or ‘Zero’ should change

Also "True" is not a defined variable in R. TRUE is.

so the snippet fails to execute

> mxMatrix(
+ type="Full",
+ nrow=1,
+ ncol=2,
+ free=True,
+ values=c(0,0),
+ dimnames=list(NULL, selVars),
+ name="expMean"
+ )

In the interest of moving forward, I have put together a proposal for representing ordinal data in OpenMx. The scope of this proposal shall be limited to ordinal data; further discussion on how to represent other data types in OpenMx shall be released in another forthcoming proposal. Corrections or comments to this proposal are encouraged. Alternative proposals are also encouraged, and should start a new forum topic [Ordinal Data Proposal (#n)].

i am following up here on the discussion previously started on the email list. i'm still unsure, after perusing the code and the npsol manual as to weather the raw likelihood or the -2 log likelihood is being returned from the optimizer. i'm wondering if anyone might know where i could find this info? or how i might reasonably search for it in the code (?)

Hi
There are two paths called β_yz in the un-titled figure currently on page 26

Seems that one should be β_x and the other β_z (the one that is currently β_y should be β₀)?

Similar issue in the simple regression figure (unlabeled, but currently on page 22)

Somewhere around here in the documentation some explanation of the triangle should be given too: I think users will be wondering:

If it's a mean, how can it be connected to all three variables?

Hi, I was wanting to get the diagonal of an openmx output matrix and tried "diag()" as shown below with the matrix.

Question: should (can?) we overload "standard" R functions, or is there to be an mxDiag() equivalent?

If the latter, it would be nice if where possible it worked (to parameters) as the {base} library functions do.

I guess that it would be VERY helpful if code like

   a = mxRun(factorModel)
  round(diag(a$S), 2) # worked, i.e, output a matrix rounded to 2 decimal places

> diag(a$S)
Error in y[1L + 0L:(m - 1L) * (n + 1L)] <- x : 

The regression example (2.1.1 Simple Regression)

states y = β₀ + β ₁ ∗ x + ϵ

Then in the text below the parameters are called " β0 , β1 , σ2, ϵ , and the mean and variance of x".

And then in the diagram we see σ²_x ,σ²_y, β_y, β_yz and μ_x.

I am beginning to think about how to work up discussion of the GUI. But to discuss the GUI without images seems unnecessarily difficult.

Of course, we can include images by linking externally. Place the image on some publicly accessible spot (picasa, photobucket, smugmug, etc.) and link to it.

But should there be some easy way to include images in a forum post?

I am wondering if we should come to a consensus about how to format code blocks and output blocks as we post them to the forums.

It seems to me that it would be nice to choose a format that would automatically preserve text spacing and tabs so that things don't become left justified when we want them indented. It would also be nice if a fixed pitch font were chosen. I don't think we need to go as far as syntax coloring. But if the block were highlighted in some way, that would be useful.