Help me figure out what the error is. This is the first time I use matlab. Optimization problem with thirteen variables.

My task is to solve the target function, which is the sum of the total costs of purchasing and using reactive power compensation devices in medium voltage electrical networks. I need to minimize it.

For now, conditionally, there should be a reactive power compensation device(PCD) on each load.

I have formed a target function from three variables (capital costs, costs of energy loss in the network and costs depending on the reliability of the system).

Since the third variable does not depend on the PCD, it can be ignored. I have divided the target function into two to find their minima. I'll shorten the calculations, the final function in the matlab looks like this:

function f=fun1_optim(x)

f(1) = 266.214+0.256*(x(1)+x(2)+x(3)+x(4)+x(5)+x(6)+x(7)+x(8)+x(9)+x(10)+x(11)+x(12)+x(13));
f(2) = 23.37*0.05*((sqrt(100^2+(90-x(1))^2))/(sqrt(3)*10^2)...
    +(sqrt(150^2+(130-x(2))^2))/(sqrt(3)*10^2)...
    +(sqrt(210^2+(180-x(3))^2))/(sqrt(3)*10^2)...
    +(sqrt(300^2+(250-x(4))^2))/(sqrt(3)*10^2)...
    +(sqrt(100^2+(90-x(5))^2))/(sqrt(3)*10^2)...
    +(sqrt(600^2+(450-x(6))^2))/(sqrt(3)*10^2)...
    +(sqrt(400^2+(390-x(7))^2))/(sqrt(3)*10^2)...
    +(sqrt(100^2+(90-x(8))^2))/(sqrt(3)*10^2)...
    +(sqrt(150^2+(130-x(9))^2))/(sqrt(3)*10^2)...
    +(sqrt(180^2+(162-x(10))^2))/(sqrt(3)*10^2)...
    +(sqrt(600^2+(450-x(11))^2))/(sqrt(3)*10^2)...
    +(sqrt(500^2+(470-x(12))^2))/(sqrt(3)*10^2)...
    +(sqrt(100^2+(90-x(13))^2))/(sqrt(3)*10^2));

and here is the error:

I sincerely don't understand what they want from me. Please help me.

[Torsten]

f must be one single value, not an array of two values (f(1) and f(2)).

Answer 1

[Torsten]

x0 = zeros(13,1);
lb = zeros(13,1);
ub = inf(13,1);
sol = fmincon(@fun1_optim,x0,[],[],[],[],lb,ub)

Local minimum found that satisfies the constraints.

Optimization completed because the objective function is non-decreasing in 
feasible directions, to within the value of the optimality tolerance,
and constraints are satisfied to within the value of the constraint tolerance.

sol = 13×1

1.0e-07 * 0.8139 0.7857 0.8161 0.8162 0.8139 0.7704 0.7988 0.8060 0.8081 0.8285

fun1_optim(sol)

ans = 30.9608

function F=fun1_optim(x)
f(1) = 0.256*(x(1)+x(2)+x(3)+x(4)+x(5)+x(6)+x(7)+x(8)+x(9)+x(10)+x(11)+x(12)+x(13));
f(2) = 23.37*0.05*((sqrt(100^2+(90-x(1))^2))/(sqrt(3)*10^2)...
    +(sqrt(150^2+(130-x(2))^2))/(sqrt(3)*10^2)...
    +(sqrt(210^2+(180-x(3))^2))/(sqrt(3)*10^2)...
    +(sqrt(300^2+(250-x(4))^2))/(sqrt(3)*10^2)...
    +(sqrt(100^2+(90-x(5))^2))/(sqrt(3)*10^2)...
    +(sqrt(600^2+(450-x(6))^2))/(sqrt(3)*10^2)...
    +(sqrt(400^2+(390-x(7))^2))/(sqrt(3)*10^2)...
    +(sqrt(100^2+(90-x(8))^2))/(sqrt(3)*10^2)...
    +(sqrt(150^2+(130-x(9))^2))/(sqrt(3)*10^2)...
    +(sqrt(180^2+(162-x(10))^2))/(sqrt(3)*10^2)...
    +(sqrt(600^2+(450-x(11))^2))/(sqrt(3)*10^2)...
    +(sqrt(500^2+(470-x(12))^2))/(sqrt(3)*10^2)...
    +(sqrt(100^2+(90-x(13))^2))/(sqrt(3)*10^2));
F = f(1) + f(2);
end

[Ivan]

Error: File: fun1_optim.m Line: 18 Column: 1

This statement is not inside any function.

(It follows the END that terminates the definition of the function "fun1_optim".)

Error in fmincon (line 563)

initVals.f = feval(funfcn{3},X,varargin{:});

Caused by:

Failure in initial objective function evaluation. FMINCON cannot continue.

am I entering something wrong or not in the right place?

[Matt J]

Show the result of,

fun1_optim(x0)

[Dyuman Joshi]

Remove the 18th line in the function fun1_optim file and run the code again.

[Ivan]

Matt J

Show the result of,

fun1_optim(x0)

Where should I insert this line at what point?

Dyuman Joshi

Deleting the 18th line in the fun1_optim function file did not help. The same mistake.

[Matt J]

Where should I insert this line at what point?

Run this as standalone code. Run it anywhere where fun1_optim is visible to Matlab, and paste the result for us,

x0 = zeros(13,1);
lb = zeros(13,1);
ub = inf(13,1);

fun1_optim(x0)

[Walter Roberson]

The error is occurring in fun1_optim.m but you are showing us fun1_optim.mlx

[Dyuman Joshi]

I wonder if there is a precendence when calling, where there is a function and a live function with the same name.

[Walter Roberson]

https://www.mathworks.com/help/matlab/matlab_prog/function-precedence-order.html

mlx has precedence 6

p has precedence 7

m has precedence 8

[Dyuman Joshi]

Thank you for sharing that information, Walter.

However, in that case, when OP uses "fun1_optim" to call, shouldn't the function with .mlx extension be called?

[Ivan]

Where should I go to see fun1_optim.m?

[Walter Roberson]

edit fun1_optim.m

[Ivan]

I entered edit fun1_optim.m There's nothing here

[Dyuman Joshi]

Run this command and see where the file is located.

which fun1_optim.m -all

[Ivan]

[Dyuman Joshi]

There's a missing word, "which", from the command.