RMKirkpatrick

Just for the record: as I explained [here](https://github.com/OpenMx/OpenMx/issues/108#issuecomment-473469531), I believe this issue is related to issue #108 . Also, this issue seems to be specific to redundant _equality_ constraints. Concerning...

#(3) from my OP (specific to Nelder-Mead) is as resolved as it'g going to get as of 12ca163 .

As of cd50601 , CSOLNP no longer hangs when running [180926--CSOLNP_hangs.R.txt](https://github.com/OpenMx/OpenMx/files/2424588/180926--CSOLNP_hangs.R.txt) (which uses redundant equality constraints). I can tell its not getting stuck in a closed loop because the non-persistent...

The ideal fix for issue (2) in my OP would be to teach SLSQP and CSOLNP to detect and work around redundant equality constraints. Our API to SLSQP already has...

Interestingly, Mplus also chokes on redundant equality constraints: http://www.statmodel.com/discussion/messages/13/24676.html?1509391097 http://www.statmodel.com/discussion/messages/13/20479.html?1551835675

> I think at the very least we should detect them and notify the user. That's currently the plan, at least in the case where the model _df_ needs to...

See 3a30d62 and 9f29afa . The MxComputeNumericDeriv step now checks to see if the equality-constraint Jacobian is full rank, and if not, stores the count of extraneous equality constraints and...

I have a reasonably clear idea how I might change our interface to SLSQP to make it robust to linearly dependent equalities generally. But, after trying today to improve CSOLNP...

> Please test a few constrained MxModels to see if the new code gives false alarms. I already verified that it gives true positives to the two redundant-equality models in...

Look at 570eb68 . It's a failed attempt to get CSOLNP to filter out redundant rows of the constraint Jacobian, and set the redundant constraint functions to zero. However, a...