i am getting the following error while i am runnig water cycle algorithm, for optimum location placing DG pleasae please help me how to solve this issue. i am attaching files

Array indices must be positive integers or logical values.

Error in WCA (line 45)

pop(i).cost=objective_function(pop(i).position);

Error in BackwardFarwardNew_28bus (line 126)

[Xmin,Fmin,NFEs,Elapsed_Time]=WCA(objective_function,LB,UB,nvars,Npop,Nsr,dmax,max_it)

i am really facing this issue, its an important work please answer as soon as possible

Answer 1

[Walter Roberson]

objective_function is expected to be a function handle, but you are passing in a numeric value instead.

[AR Hithesh]

Thank you so much for your replay, but I am student and beginner, can you please tell me in detail

[Walter Roberson]

In BackwardFarwardNew_28bus.m you have

objective_function = min(P_l);
[Xmin,Fmin,NFEs,Elapsed_Time]=WCA(objective_function,LB,UB,nvars,Npop,Nsr,dmax,max_it)

so you are taking min() of something and passing it in as objective_function .

What is that thing, P_l ? Well, you have

   for i=size(LD,1):-1:1
        c=[];
        P_l = [];
        e=[];
        [c e]=find(LD(:,2:3)==LD(i,3));
        if size(c,1)-1==0
            IB(LD(i,1))=I(LD(i,3));
            x = LD(:,4);
            P_l = real(((IB(LD(i,1)))^2).*x)
        else
             IB(LD(i,1))=I(LD(i,3))+sum(IB(LD(c,1)))-IB(LD(i,1));
             x =LD(:,4);
                P_l = real(((IB(LD(i,1)))^2).*x)
        end

    end

That runs a loop (backwards), and every iteration of the loop it resets all of P_l to empty, and then it sets P_l to P_l = real(((IB(LD(i,1)))^2).*x) where x = LD(:,4); looks like a column vector. So P_l appears that it will be a column vector after the for loop. With the .* operator, it is most likely numeric, but at the moment we cannot rule out symbolic or even something more strange such as transfer function.

So what is IB ?

    IB=zeros(size(LD,1),1);

That is numeric, as was most likely.

So, you loop backwards over the rows of LD, and each time you overwrite all of P_l with a numeric vector. Then afterwards you take min() of the numeric vector, giving a numeric scalar result. And you pass that numeric scalar result into WCA.

What does WCA do with it?

% Water Cycle Algorithm (WCA) (Standard Version)
% This code is prepared for single objective function (minimization), unconstrained, and continuous problems.

so WCA is expecting to minimize a function. Most likely the first parameter,

function [Xmin,Fmin,NFEs,Elapsed_Time]=WCA(objective_function,LB,UB,nvars,Npop,Nsr,dmax,max_it)

objective_function. But you passed a numeric scalar into that position.

    pop(i).cost=objective_function(pop(i).position);

objective_function is a numeric scalar. The only valid indices for it are scalar true, any number of false, and any number of numeric 1 . But

   pop(i).position=LB+(UB-LB).*rand(1,nvars);

That is not going to be true, false, or 1.

You need to review your BackwardFarwardNew_28bus.m and figure out what it is that you want to minimize. You need to be passing in a function handle, and the function handle has to expect to receive (in the context of your code) a vector of length 6, and the function handle has to return a scalar numeric value.

[AR Hithesh]

sir, i am actually looking for help to develop a function handle, the main objective of the code is to find the Xmin, Fmin its nothing optimal location to place DG (distributed generation like solar array, wind power) to compensate the losses at particular bus in a radial feeder, in distribution system, hence i have to find the bus with maximum loss and min voltage using WCA.m. to do this i am stuck in the situation.

I pleasing you to help me how to write a function handle for that particular problem, i am trying my best towards the work, but as i am beginner for algorithm development, i am seeking you help. Could you please help me in the work.?

and BackwardFarward_28bus is a algorithm which calculates the current, voltage and power at each bus of the 28 bus radial distribution system.

i hope the points are very clear, to you for further discussion please let me know, and i seeking you help sir..

thank you

[Walter Roberson]

You need to make BackwardFarward_28bus into a function, that given a particular "position", calculates the current, voltage and power at each bus, and returns them.

Then you need to make another function that, given a particular "position", calls BackwardFarward_28bus and receives back the current, voltage and power lists, and uses those to calculate a weighted loss measurement to get a scalar that estimates how good that particular position is. This will be your objective_function

Then you need to have code (either a function or a script) that initializes variables and calls WCA passing in the objective function (which will call the new BackwardFarward_28bus function to create the vectors of values and then summarize the values into a scalar "goodness")

[AR Hithesh]

sir i am so glad for your reply, thank you so much, if possible can you please develop that certain part of code ? please can you help me.

finally i should get Xmin, Fmin, ie output from the wca, it wil be so grateful ...

[Walter Roberson]

No, I do not know how you want to go from the values calculated for the busses into a single loss value, and I do not know how you want to calculate the bus values from a proposed position.

[AR Hithesh]

sure sir, thank you for your valuable information and help, for futher help i wll approach you, thank you so much