[Ipopt] Posting Ipopt Problems for help

Tony Kelman kelman at berkeley.edu
Thu Nov 8 12:49:17 EST 2012

Which folder did you add to the Matlab path? If you do "make install" then 
you should add the "lib" directory to the Matlab path - it will contain both 
the ipopt.mexw32 file and an ipopt.m file which contains commented help 
text. If you don't do "make install", the ipopt.m file is located one folder 
above the "src" directory. You can also access the ipopt.m help file at 

The print level of ipopt can be modified in the Matlab interface by setting 
options.ipopt.print_level to some value between 0 and 12 (default is 5). See 
http://www.coin-or.org/Ipopt/documentation/node59.html for a list of other 
Ipopt options you can modify in a similar way - a small number of them might 
not be implemented with the Matlab interface, but most should be.

Someone contacted me offline recently with a similar issue in the Matlab 
interface, where he encountered the "Invalid number" message and observed 
non-repeatable results. I believe this may happen if your gradient of 
objective function outputs a Matlab sparse vector, the mex file might try to 
access data beyond the valid memory addresses in the gradient array. I'll 
look at the Matlab interface source code in a bit more detail to figure out 
if/how it handles this case and I'll see if I can fix any confusing 
behavior. In the meantime, make sure your gradient function outputs a full() 


-----Original Message----- 
From: ??? <chambertinofn at gmail.com>
Date: Wed, 7 Nov 2012 22:13:42 +0800
To: Stefan Vigerske <stefan at math.hu-berlin.de>
Cc: ipopt at list.coin-or.org
Subject: Re: [Ipopt] Posting Ipopt Problems for help

Thank you.
I'll try printing the function evaluations on the screen to trace the
program. But as for increasing the print level of ipopt, I don't know how
to do it.
In the tutorial on the official website, it's said that after the compile
of the ipopt matlab interface, I can get the usage instruction of it by
typing 'help ipopt' in the matlab prompt like the other matlab original
functions if I set the ipopt.mexw32 directory in the 'set path' window. But
after those procedure including compile and setting path, I actually get
'ipopt not found' instead of any usage instruction when I typed 'help
ipopt'. So the only way to learn how to use ipopt matlab interface is the
four examples in the ipopt source code.
So if there's any detail usage document of the ipopt matlab interface,
please send me a copy.
Thank you very much.
Neo Ma ??? | Graduate

T:+86-10-6278 2545 | E:chambertinofn at gmail.com
Dept. of Electrical Engineering, Tsinghua Univ.
BLDG. 28# RM.312 Tsinghua Univ. Beijing 100084 P.R.CHINA
Remember what should be remembered, and forget what should be forgotten.
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