how do i write a constraint and the sum of the z value?

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sharifah shuthairah syed abdullah
评论： Walter Roberson 2018-6-10
i have the code and i try to make x as constraint but when i run i always get an error said that Undefined function or variable 'x'. below is the code and how can i get the sum of the z value?
clc;
clear;
%sum sum sum sum(fik*djq*xij*xkq)
%i,k= facilities
%j,q= location
%f(i,k)= flow between facilities i and k
%d(j,q)= distance between locations j and q
%xij = 1 if facility i is assigned to location j and if otherwise, xij = 0
% Flow matrix: flow assigning facility i (column) to facility k (row)
f = [0 5 7 9;
5 0 4 6;
7 4 0 3;
9 6 3 0];
%Distance matrix: distance assigning location j (column) to location q (row)
d = [0 6 8 9;
6 0 5 1;
8 5 0 2;
9 1 2 0];
z= 0;
nf= 4;%no of facilities
nd= 4;%no of locations
for i=1:nf
for j=1:nf
for k=1:nd
for q=1:nd
z = min('z','sum(sum(f(i,k)*d(j,q)*x(i,j)*x(k,q)))');
%if x(i,j)==1;
%else x(k,q)==0;
end
end
end
end
%Constraints %x as binary 0 1, %x(i,j) = 1 if facility i is assigned to location j 0r otherwise, x(i,j) = 0
Constraints.constr1 = (x(i,j))==1;
%The first set of constraints requires that each facility gets exactly one %location, that is for each facility, the sum of the location values %corresponding to that facility is exactly one
Constraints.constr2 = sum(x,2) == 1;
%The second set of constraints are inequalities. These constraints specify %that each office has no more than one facility in it.
Constraints.constr3 = sum(x,1) == 1;
disp (z);
are the constraint i code is wrong? and how can i get the sum of z value?
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sharifah shuthairah syed abdullah
sharifah shuthairah syed abdullah 2018-6-10
if i put it like this
x = [0 1 0 0;
1 0 1 0;
0 1 0 1;
0 0 1 0];
Constraints.constr1 = (x(i,j))==1;
then error came out and said Index in position 1 is invalid. Array indices must be positive integers or logical values.
Walter Roberson
Walter Roberson 2018-6-10
If you tried to do that before your for i loop, then i would not have been defined, and would have the default value of sqrt(-1)

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