Taking data from matrix and using it in a function
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Let's denote . I would like to find the maximum value of the function z, if I substitute with -1 or 1. I created a matrix of only -1 and 1 using de2bi function (I got 0's and 1's but substituted 0's with -1's). How can I "connect" the matrix with my function, so that I'll check all possible combinations and get the maximum value?
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Birdman
on 1 Apr 2020
Edited: Birdman
on 1 Apr 2020
As far as I understand, you want to change E1, E2, E3 and E4 respectively with combinations of -1 and 1. So the following code does that:
syms z(x,y) E1 E2 E3 E4
z(x,y)=(((sin(x).*(1+E1))./(3))+(1+E2))./(log10(y+E3)-E4);
A=perms([-1 1 -1 1]);
for i=1:size(A,1)
Z(x,y)=subs(z,{E1,E2,E3,E4},{A(i,1),A(i,2),A(i,3),A(i,4)})
end
After this point, you can proceed. If you have further question, we can discuss from here. Hope this gives the idea.
3 Comments
Birdman
on 1 Apr 2020
Try the following code. Note that I had to set x as
x = linspace(1,10,100);
to reduce the calculation time. The max values are stored in
Z_max
syms z(x,y) E1 E2 E3 E4
z(x,y)=(((sin(x).*(1+E1))./(3))+(1+E2))./(log10(y+E3)-E4);
A=perms([-1 1 -1 1]);
c = linspace(1,10,100);
d=c;
[C,D] = meshgrid(c,d);
for i=1:length(A)
Z(x,y)=subs(z,{E1,E2,E3,E4},{A(i,1),A(i,2),A(i,3),A(i,4)});
Z_max(i) = max(max(double(vpa(Z(C,D),2))));
figure(i);
fsurf(Z,[1,10,1,10])
end
The code takes some time to be calculated.
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