[Ipopt] Where or how can I obtain the libhsl.dll?

[Lewis I]

Oh...
I can solve it now.
I have deleted too many lines in libhsl.def.
There should be 4 lines if i only use ma27.
@@EXPORTS
@@    MA27ID
@@    MA27AD
@@    MA27BD
@@    MA27CD

But one more question, i do not find a obvious change when i change between mumps and hsl method. Do they only show a difference in large scale problem?

And which linear solver in ipopt is the more common solver when solving large scale problem? (mean which one usually has the best performance?)

Thx

Lewis