[Coin-ipopt] Re: IPOPT 3 Memory question

[Rhoda Baker]

Hi Andreas,

I thought I'd follow up on some of the suggestions you offered. I have 
also joined the mailing list in case others are interested in my 
experiences. :)

> 1. The problem with MA27 is that it is written in Fortran 77, and 
> doesn't have dynamic memory allocation.  Therefore, Ipopt has to guess 
> beforehand, how much memory MA27 requires (based on the number of 
> nonzeros).  The options ma27_liw_init_factor and ma27_la_init_factor 
> determine this initial guess of MA27's memory requirement.  If during 
> the factorization MA27 complains that it doesn't have enough memory, the 
> guesses are increased by some factor, and that factor is the value of 
> the option ma27_meminc_factor.  Now, the default of that second option 
> is "10", which is maybe too aggressive. I would try smaller values (say, 
> 2 or 3) in your case.

The first thing I tried was to set the ma27_meminc_factor to 10. 
However, it says that it does not recognize that option. Using ipopt -= 
confirms that the options for ma27_liw_init_factor, ma27_la_init_factor 
and ma27_meminc_factor are not available. However, ma27_pivtol and 
ma27_pivtolmax are present, which would seem to indicate that I have 
included compiled ma27. I'm not quite sure what I'm doing wrong here. I 
even tried recompiling, and as far as 'make test' was concerned 
everything was a-ok.

In the meantime, I am trying out mumps and have upgraded to version 
IPOPT 3.3.2 from 3.2.4.

Cheers
Rhoda