What's wrong with my objective function?

Hello

When I run this line of code,

[d,fval] = fseminf(@objfun,x0,numOfInequations,@semInfConstraints);

I get the following error:

Input arguments to function include colon operator. To input the colon character, use ':' instead.
Error in fseminf (line 424)
initVals.f = initVals.f(:);
Error in optimize (line 29)
[d,fval] = fseminf(@objfun,x0,numOfIneqs,@semInfConstraints); 

Here is my objective function:

function f = objfun(D,s)
global numOfVars
% Objective function, -1*D(1)*D(2)*...*D(n) /n dimension/
str = 'f=@(D) -1*';
dimension = numOfVars;
for i=1:dimension
    if i<dimension 
        str = join([str 'D(' string(i) ')*'],'');
    else
        str = join([str 'D(' string(i) ');'],'');
    end
    
end
eval(str);

[Richárd Tóth]

Or maybe something is wrong with semInfConstraints...

[Richárd Tóth]

Okay, I think the problem is

str = 'f=@(D) -1*';

By removing the @(D), I no longer get the error message about the colon.

[Star Strider]

If you want to create a functon from a string, use the str2func function. It likely does everything you’re doing, however it’s more straightforward. Also,using sprintf to create your function strings is likely more efficient than concatenating strings.