Sum of Least Squares

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Robert Demyanovich
Robert Demyanovich 2021-10-4
回答： John 2023-7-31
I have a table, Check, where I would like to subtract column 6 from column 5 (to obtain a residual) and then square the residual. Then for all of the rows I would like to sum the squares of the residuals. Since MATLAB is supposed to be able to handle working with matrices and arrays much better than say visual basic, it seems I should be able to do this with one or two lines of codes. Maybe something like:
Check(:,7) = (Check(:,5) - Check(:,6))^2
SumofSquares = sum(Check(:,7)
  1 个评论
Mathieu NOE
Mathieu NOE 2021-10-4
hi
you can do in one line .
SumofSquares = sum((Check(:,5) - Check(:,6)).^2);

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采纳的回答

Siddharth Bhutiya
Siddharth Bhutiya 2021-10-4
You would have to use curly braces {} indexing in order to do this. Using () will give you a table and operations like subtraction, addition, etc are not defined for tables. Using {} would give you the contents of the table, which could then be used to do what you want.
>> Check = array2table(magic(6));
>> Check{:,7} = (Check{:,5} - Check{:,6}).^2;
>> SumOfSquares = sum(Check{:,7})
SumOfSquares =
156
  2 个评论
Robert Demyanovich
Robert Demyanovich 2021-10-4
Mathieu NOE's answer works. So it wasn't a table but a matrix (I guess)
Matt J
Matt J 2021-10-4
@Robert Demyanovich But the answer given by @Siddharth Bhutiya is correct with respect to your stated question, so you should Accept-click it.

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更多回答（1 个）

John
John 2023-7-31
xi = [1491214 17];
yi = [-3.97, 5.18, 20.43, 29.58, 35.68, 44.83];
n = length(xi);
A = [n sum(xi); sum(xi) sum(xi.^2)];
C = [sum(yi); sum(xi.*yi)];
Z = A\C;
a =Z(1);
b = Z(2);
fprintf ('y = %.5f + %.5f x \n',a,b)

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