# fminsearchbnd optimization function in matlab

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mohammed hussein on 2 Dec 2015
Answered: MASTER WHOS on 8 Feb 2019
i used fminsearchbnd for boundary problem but the matlab it tell me that Undefined function 'fminsearchbnd' can any one help me with is problem i used this example
fun = @(x)(x(1)-5)^2+(x(2)+6)^2+x(3); % x0 = [0 0 0]; Lb=[0 -1 2]; Ub=[1 2 3]; [x,fval,exitflag,output] = fminsearchbnd(fun,Lb,Ub); disp(fval)
thank you

Walter Roberson on 2 Dec 2015
fminsearchbnd is not part of MATLAB. You can get it one of the versions from the File Exchange
mohammed hussein on 2 Dec 2015
Thank you very much

MASTER WHOS on 7 Feb 2019
I DID THIS:
Do not put it in the MATLAB toolbox. Download the .zip file, and unzip it into a directory that has nothing else in it (and which is not under the MATLAB installation.) Then use pathtool to add the directory to the MATLAB path. After that MATLAB will be able to find the file.
but it gives error: Error in fminsearchbnd (line 264)
[xu,fval,exitflag,output] = fminsearch(intrafun,x0u,options,varargin);
what might be the problem?
Walter Roberson on 8 Feb 2019
I have my own private implementation of tricking fminsearch into being bounded (stops when it hits the boundary rather than reflecting as might be nice.)
I know from experience that 55 variables is completely intractable to use seriously with fminsearch . fminsearch gets caught in local minima , not as easily as fmincon gets caught but it happens all the time. It is not a global minimizer. To use it for more than light use you need to start it at multiple locations . In particular you need starting points near every valid combination of upper and lower bounds . With 55 variables that would be 2^55 configuration to examine. If you could process 2^30 per second (gigaflop range ) then that would take you 2^25 seconds . That would be a year . You probably cannot process more than 1/100 of that speed so probably 100 or so years . Just for figuring out crudely which end of each bound you probably near.

MASTER WHOS on 8 Feb 2019
sorry, so, is that the only problem? [missing @SQP_complex2, & @SQP_complex2_case2] (which bring the error I attached with fminsearchbnd)?
##### 2 CommentsShowHide 1 older comment
Walter Roberson on 8 Feb 2019
There is @ missing before SQP_complex_case2 unless that is a function that returns aa function handle.

MASTER WHOS on 8 Feb 2019
Ok, thank you

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