[Minotaur] The supported ampl function

[Ashutosh Mahajan]

Jason,

It may still be possible to 'solve' your problem with minotaur by using the option

--use_native_cgraph 0

The equivalent code in AMPL is 
option solver bnb;
option bnb_options "--use_native_cgraph 0";
solve;

This option asks minotaur to use gradients and hessian directly from AMPL, and not rely on its own inbuilt routines. If AMPL provides consistent derivatives for these opeartions, then it may work.

Ashutosh.

----- Original Message -----
From: "Ashutosh Mahajan" <mahajan at mcs.anl.gov>
To: "Jiaxin Liu" <ljx871206 at gmail.com>
Cc: minotaur at lists.mcs.anl.gov
Sent: Wednesday, December 19, 2012 5:30:59 PM
Subject: Re: [Minotaur] The supported ampl function

Hi Jason,

Currently only operations listed in the file
src/base/OpCode.h
of the source code are supported. None of the operations you mention below are
supported. You will have to reformulate your problem to make it work with
Minotaur.

Is it possible for you to share your model so that it helps us in adding
support for it in the future? We can keep you posted when it happens. Thanks. 

--
Regards
Ashutosh Mahajan

On Wed, Dec 19, 2012 at 01:37:01AM -0500, Jiaxin Liu wrote:
> Hi Minotaur Developers,
> 
> I am a new user from University of Waterloo. I was trying to model a non-linear
> piecewise smooth function, which is essentially a ceiling function of a smooth
> decreasing convex function, where the ceiling criteria is specified by a set of
> variables. I was trying to use if-then-else, the piecewise linear program and
> the maximum function to model my function, but none is supported (OPINFI,
> OPPLTERM, OPMAX respectively).  I was wondering if there is anything I can do
> in Minotaur to formulate my function, and if the users are allowed to view the
> list of unsupported ampl functions.
> 
> Thanks,
> Jason

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