depot Location allocation problem

Hello,

I am trying to solve a depot location allocation problem . I am unable to formulate and solve it in MATLAB. Can anyone help me solve this problem?

Answer 1

[Alan Weiss]

Maybe you could put your problem in an MILP framework, along the lines as this Travelling Salesman Problem example. Notice that, despite the nonlinear distances, the problem itself is linear.

This example might also be relevant: Factory, Warehouse, Sales Allocation Model.

Alan Weiss

MATLAB mathematical toolbox documentation

[blitz]

Thanks Alan, I have figured out to code this but still my solution doesn't converge to optimum rather it stays at my initial guess of depot locations. Here is my code. This is for 4 customers and 3 depots. Code doesn't give any error but location of my depot doesn't change from what i give in initial guess. Can you find out what I am missing here? Thanks

fun2=@(z)cost_function2(zvectorized,Cvec,M,N); options = optimoptions(@fmincon,'Algorithm','sqp'); options.Display='iter'; [zfinal,fval,exitflag,output]=fmincon(fun2,z0,[],[],Aeq,beq,lb,[],[],options);

Cost function:

function cost = cost_function2(Z,Cvec,M,N) %UNTITLED4 Summary of this function goes here xcoeff=Z(1:2*M,1); Xvec=reshape(xcoeff,2,M); tcoeff=Z((2*M)+1:(M*N)+2*M,1); t=reshape(tcoeff,M,N); cost=0;

for i=1:M for j=1:N cost=cost+t(i,j)*sqrt((Xvec(:,i)-Cvec(:,j))'*(Xvec(:,i)-Cvec(:,j))); end end end

OUTPUT:

zfinal =

         0
         0
         0
         0
         0
         0
    1.6667
    1.6667
    1.6667
    2.0000
    2.0000
    2.0000
    2.3333
    2.3333
    2.3333
    1.3333
    1.3333
    1.3333

So locations are all zeros which mean the solution wasn't obtained. Please help.

[Alan Weiss]

It would be much easier for us to read your question if you would format the MATLAB code using the {} Code button.

I do not understand your code, but then I have trouble reading it because of the formatting. Nevertheless, I think I found an error:

 fun2=@(z)cost_function2(zvectorized,Cvec,M,N);

It seems to me that fun2 returns a constant no matter what value you put in for z. Perhaps you meant

 fun2=@(zvectorized)cost_function2(zvectorized,Cvec,M,N);

Alan Weiss

MATLAB mathematical toolbox documentation

[blitz]

Thank you so much! You're awesome, that worked. I just couldn't believe I was missing such a detail. I up-voted the answer. Sorry about the bad arrangement of code. I am new to this and didn't know about it. I thank you once again.

[Image Analyst]

Please read this: http://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup

In the meantime, Mathworkers and others with enough reputation points can "Edit" the post to see the code in a form better for viewing and copying and pasting.