# .Selecting the data series for next loop

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Prakhar Modi on 6 Aug 2019
Commented: Prakhar Modi on 9 Aug 2019
Hello Everyone,
I have 1 main series lets say it as y and 5 sub series lets say it as x1.
Now I am calculating z1 using the equation z1= y-x1.
and then I am calculating the coefficient of determination that is R^2. Now what I want is that as from 5 x1 I will get 5 z1 series which will give me 5 R^2, so now I want that code should select the x1 series which gives maximum value of R^2 and assign it as x1 series for further computation.
After this, of the remaining 4 x1 series, which will be taken as x2 series, i again want to calculate z2 using the equation z2=y-x1-x2. Here x1 and y are fixed where as x2 is changing. I have done this in excel but I have lot of series. I just want to know how to direct the code to select the series of maximum R^2.

Bob Nbob on 6 Aug 2019
Is y a single value?
I'm not entirely sure I know what you're asking for, but maybe something like this can work?
y = randi(100,1,1);
x = randi(50,5,1);
c = 1;
xc = [];
while length(x)>1
z = y-sum(xc)-x; % Calculate z values for all x
xc(c) = x(z==max(z)); % Record x which results in max z ( I know you want max R^2 but you didn't give a relationship for z and R^2)
x = x(x~=xc(c)); % Remove recorded x value from x
c = c + 1;
end
xc(c) = x; % Record last value of x

Prakhar Modi on 7 Aug 2019
ok thanks I will try this.
Prakhar Modi on 9 Aug 2019
Hello Bob,
whatever you suggested was correct but now I am stuck with something else. The thing is I got the way to remove x because it is present in equation of z, but in my code as x is 15x1 matrix and similarly y is 15x1 matrix and while calculating z I am not directly using x in the equation. let say I am computing p from x than q and than q is used to calculate z. But ultimately I have to remove the x which 15x1 matrix for further computation. So do you have any more suggestions.

R2018a

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