Error in fmincon: undefined getIpOptions

Good evening,

I am trying to use fmincon to fit a multinomial tree model to behavioural data. I'm aware that other questions have been asked about the same error, but those questions haven't been resolved (see for example https://de.mathworks.com/matlabcentral/answers/447671-error-in-fmincon-getipoptions-not-found) and wouldn't apply in my case anyway. Five parameters, each with the lower bound [0] and the upper bound [1], are to be estimated to minimize a G-squared estimate of goodness of fit (expressed in a customized function "Goodness_of_Fit_1", which itself works fine). No other constraints apply here, resulting in the following syntax:

fmincon(@Goodness_of_Fit_1, [0,0,0,0,0], [],[],[],[],[0,0,0,0,0],[1,1,1,1,1])

However, this returns the following error:

Undefined function or variable 'getIpOptions'.

Error in fmincon (line 811)
    options = getIpOptions(options,sizes.nVar,mEq,flags.constr,defaultopt,10,0.01);

I am using Matlab R2018b and the path to fmincon is correct (uses the same version).

Thank you very much for your help!

[Matt J]

What happens when you do

>> which -all getIpOptions

[Lukas Meyerolbersleben]

Then it returns:

'getIpOptions' not found.

Answer 1

[Jim Hokanson]

I had this problem and just reinstalled the optimizaton toolbox ...

[Ali Eren Sürmeli]

It also worked for me

[Vivian Toca Díaz]

how did u do that?

[alok kumar]

There is a add-on option at top right side. you can search for optimization toolbox there.

Answer 2

[Matt J]

Well, it should be there. On my machine,

>> which -all getIpOptions
F:\Program Files\MATLAB\R2018b\toolbox\optim\optim\getIpOptions.m

I suggest you check your anti-virus software to see if it may have quarantined it. Then, I would do a complete clean re-install. By clean reinstall, I mean you first delete any existing R2018b folders.

[Lukas Meyerolbersleben]

Well, my anti-virus software didn't quarantine it. As soon as I've reinstalled Matlab, I'll post here whether that does the trick. In the meantime, thank you very much for your help!

[Marcelo Fernandes]

For anyone having this problem, it appears to happen when you install a new version of MATLAB and uninstall the older versions from the computer - in this order. It could be that those files (such as getIpOptions.m) have not been installed because of previous files on the computer.

I followed Matt J's suggestion and it's fixed.

Thank you, Matt!

[Navreet Singh Thind]

Thanks a Lot! It helped