[Coin-ipopt] New: MA48 (instead of MA28) for basis selection

Andreas Waechter andreasw at watson.ibm.com
Wed Sep 11 14:06:13 EDT 2002


I have made a change in IPOPT regarding the automatic partition of
variables into dependent and independent variables.  This partition is
necessary, if you use the reduced space version or a quasi-Newton

So far, IPOPT always used the Harwell routine MA28 to obtain this
partition, even if its (assumed to be better) successor MA48 was available
and used for the factorization of the arising nonsymetric linear systems.
As of today, MA48 (in connection with MA51) is also used for obtaining the
partition if available, and MA28 is then no longer necessary.  Hopefully,
this will result in better performance.

The selection of the partition on the DYNOPT module is still performed by
MA28.  If there is a request, I will be happy to change the implementation
here as well.



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