Prev: plotting question
Next: pid tuning
From: MZ AM on 5 May 2010 12:50
Hi,

Should a nonlinear constraint function of an optimization function, such as fmincon, have only one input argument. I ran into an error as I was trying to add more input arguments in the "confun" function in the first example of

http://www.mathworks.com/access/helpdesk/help/toolbox/optim/ug/brn4nh7.html

Of course I made some changes in all the functions in this example to correctly implement the other input arguments.

Any opinion is appreciated.

Thanks
From: Steven Lord on 5 May 2010 12:57

"MZ AM" <mazamin(a)yahoo.com> wrote in message
news:hrs7ke$8sv$1(a)fred.mathworks.com...
> Hi,
>
> Should a nonlinear constraint function of an optimization function, such
> as fmincon, have only one input argument.

That depends -- what does the help and/or documentation for the function
indicate the signature of the nonlinear constraint function should be? For
FMINCON:

http://www.mathworks.com/access/helpdesk/help/toolbox/optim/ug/fmincon.html

"[Nonlcon is the] function that computes the nonlinear inequality
constraints c(x)? 0 and the nonlinear equality constraints ceq(x) = 0.
nonlcon accepts a vector x and returns the two vectors c and ceq."

That indicates that yes, the nonlinear constraint function should accept one
input argument, the vector x, and return two outputs.

> I ran into an error as I was trying to add more input arguments in the
> "confun" function in the first example of
>
> http://www.mathworks.com/access/helpdesk/help/toolbox/optim/ug/brn4nh7.html
>
> Of course I made some changes in all the functions in this example to
> correctly implement the other input arguments.
>
> Any opinion is appreciated.

Use the technique described here:

http://www.mathworks.com/support/solutions/en/data/1-19HM6/index.html?solution=1-19HM6

--
Steve Lord
slord(a)mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ


From: Alan Weiss on 5 May 2010 12:57
On 5/5/2010 12:50 PM, MZ AM wrote:
> Hi,
>
> Should a nonlinear constraint function of an optimization function, such
> as fmincon, have only one input argument. I ran into an error as I was
> trying to add more input arguments in the "confun" function in the first
> example of
>
> http://www.mathworks.com/access/helpdesk/help/toolbox/optim/ug/brn4nh7.html
>
> Of course I made some changes in all the functions in this example to
> correctly implement the other input arguments.
>
> Any opinion is appreciated.
>
> Thanks

If your question was "Should the input argument x be the same for the
objective function and the nonlinear constraint functions" then the
answer is yes. Optimization functions expect your current point x to be
the same for both constraints and objective.

You can pass extra parameters if you like to either constraints or the
objective function:
http://www.mathworks.com/access/helpdesk/help/toolbox/optim/ug/brhkghv-7.html

Alan Weiss
MATLAB mathematical toolbox documentation
 | 
Pages: 1
Prev: plotting question
Next: pid tuning