Opt rSQP was a reduced-space sequential quadratic programming solver for ASCEND that used proprietary third-party code as its calculation engine.
The ASCEND-side code for Opt rSQP is still available, in ascend/solver/slv2.c, ascend/solver/slv2.h, ascend/solver/rsqp.h, however the proprietary dependencies are no longer available to us, so the solver is most definitely dead. These files are being removed from the subversion repository at r3107, so you will need to browse our file history to locate these files.
Ben Allan has proposed that we could get this solver running again by making use of the newer free code from Opt++/Trilinos. This would not be a simple job, however, and would be a significant re-write.
Note: in the code, "This routine assumes that a struct var_variable *is an Instance. In the future this is going to change, and this routine will break.". Will certainly need some rewriting before it can be operation again.