Published on *OpenMx* (http://openmx.psyc.virginia.edu)

By *mspiegel*

Created *08/26/2009 - 10:28*

Wed, 08/26/2009 - 10:28 — mspiegel [1]

If 'compute' is FALSE (the default), then MxAlgebra expressions returns their current value as they have been computed by the optimization call (using mxRun). If the 'compute' argument is TRUE, then MxAlgebra expressions will be calculated in R. Any references to an objective function that has not yet been calculated will return a 1 x 1 matrix with a value of NA. Users will like this feature because it allows them to compare the result of algebraic expressions as computed by the back-end against those values computed by R. Developers will like this feature because we can compute all our algebra expressions before invoking the optimizer in order to check for any non-conformable matrices in our matrix operations (without having to explicitly check, R does the heavy lifting for us).

**Links:**

[1] http://openmx.psyc.virginia.edu/users/mspiegel

[2] http://openmx.psyc.virginia.edu/thread/196

[3] http://openmx.psyc.virginia.edu/thread/168

[4] http://openmx.psyc.virginia.edu/forums/openmx-developer-forums/r-functions-and-user-interface