[Ipopt] Memory limitations in Matlab-interface IPOPT when using MA27

Andreas Waechter awaechter.iems at gmail.com
Thu Aug 16 09:27:49 EDT 2012

MC19 is used to computed scaling factors for the matrix.  By default, it 
only kicks in if the linear system solutions are not accurate.  But by 
setting 'linear_scaling_on_demand" to "no", you will make sure the 
scaling happens from the beginning.  See 

Andreas Waechter

Associate Professor
Department of Industrial Engineering and Management Sciences
McCormick School of Engineering
Northwestern University
Evanston, IL 60208

On 08/16/2012 05:40 AM, Jonathan Hogg wrote:
> At a guess its because MA57 will be using scaling by default and MA27 
> will not.
> For most problems scaling makes little real difference (except that 
> MA57 runs more slowly), but for others it
> significantly reduces (or eliminates completely) need for pivoting and 
> the related growth in memory requirements.
> You can probably test this by disabling scaling in MA57 and seeing if 
> you get similar errors.
> Jonathan.
> On 16/08/12 08:39, Lemoine, Roberto wrote:
>> Dear IPOPT developers/users:
>> I have a question. I am using the Matlab-interfaced version of IPOPT 
>> v.3.10.0 (run with Matlab R2011b in a computer with Windows 7), 
>> successfully compiled as described in the Interface website:
>> bandersnatch.dyndns.info/~djr/ipopt_compile_steps.pdf
>> My optimization problem is relatively small (1000 degrees of freedom 
>> or less). However, IPOPT solves the problem successfully only if I 
>> use the linear solver MA57 (I have METIS also installed). However, 
>> when I use MA27, IPOPT fails to start iterating, and shows the 
>> failure message:
>> EXIT: Not enough memory
>> This does not happen with MA57 (even MUMPS makes it to start 
>> iterating, but fails after some iterations due to problems in the 
>> restoration phase). I have played around by increasing the parameters 
>> ma27_liw_init_factor, ma27_la_init_factor and ma27_meminc_factor, and 
>> the problem remains.
>> Does anybody have an idea why MA27 could be having this problems, 
>> while MA57 not? Is there a difference in the memory management of the 
>> solvers? Thanks a lot in advance.
>> Best regards,
>> Roberto Lemoine-Nava
>> Lehrstuhl für Systemdynamik und Prozessführung
>> Fakultät Bio- und Chemieingenieurwesen
>> Technische Universität Dortmund
>> Emil-Figge-Str. 70
>> 44221 Dortmund
>> Tel.: +49 (0) 231/755-5171
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