Set the Optimizer using umx_set_optimizer

umx can use 3 optimizers: NPSOL, SLSQP, and CSOLNP(the default).

NPSOL doesn’t ship on the CRAN version of OpenMx. It is, however, highly optimized and works well with the vast majority of models. If you’re having hassles with mxRun, or CIs, NPSOL might help.

CSOLNP often works well for ordinal models. SLSQP is often as good or better than NPSOL and has the benefit of working out of the box from CRAN.

You can see what optimizer is being used by calling umx_set_optimizer with no parameters.


Current Optimizer is: ‘CSOLNP’. Options are: ‘CSOLNP’, ‘SLSQP’, and ‘NPSOL’

Set the optimizer by name:


top tip: If you don’t see NPSOL as an option, grab the NPSOL version of OpenMx:


On MacOS, you can also get cutting-edge builds of OpenMx from our travis server:


That’s it :-)