Error using sum function

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Nour Aburaed 2018-12-26

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/437235-error-using-sum-function

编辑： Bruno Luong 2023-11-25

采纳的回答： madhan ravi

I have a 26x26 matrix 'A' of type double. I want to sum all of its elements using S = sum(A, 'all').

I keep getting the following error:

Error using sum

Invalid option. Option must be 'double', 'native', 'default', 'omitnan' or 'includenan'.

Can someone help me with this? My matrix is of the correct type, so I am not sure what's wrong.

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DGM 2023-11-25

编辑：DGM 2023-11-25

在 MATLAB Online 中打开

To extend this to what Walter said about class:

% i'm avoiding rand() hopefully avoid any version/platform
% sensitivity in generating the test array, mostly because i wanted 
% to run the test in versions prior to the introduction of rng()
X = magic(1000)/3; % X is double
SA = sum(X,'all');
abs(SA - sum(sum(X))) % error scales with data
ans = 3.0518e-05
abs(SA - sum(X(:))) % equal
ans = 0
X = single(X); % X is single
SA = sum(X,'all');
abs(SA - sum(sum(X))) % error is not insignificant
ans = single
    278528
abs(SA - sum(X(:))) % still equal
ans = single
    0

So for a 2D input, sum(sum(X)) does not give the same result, and the difference between the methods does depend on the array class, and it also depends on the version (and maybe platform) as well. I get different results on every version I've tested. But in all cases, sum(X,'all') and sum(X(:)) yield identical results.

We can question whether it's prudent to blindly try taking the sum of large single-precision arrays, but that's not really the point.

DGM 2023-11-25

Ah.

Paul 2023-11-25

编辑：Bruno Luong 2023-11-25

I assume sum(X,'all') is implemented as sum(X(:)) at the intermediate interface level before the sum hoerachy and low-level CPU instruction occurs, so I think yes, they should return the same result.

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采纳的回答

madhan ravi 2018-12-26

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https://ww2.mathworks.cn/matlabcentral/answers/437235-error-using-sum-function#answer_353927

编辑：madhan ravi 2018-12-26

在 MATLAB Online 中打开

sum(A(:)) % if it doesn't work either upload your matrix as .mat file

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madhan ravi 2018-12-26

But sir Image Analyst I’m using student version too , it works in my case though.

Steven Lord 2018-12-26

Image Analyst: clicking on the "Buy MATLAB and Simulink Student Suite" button on this page brings up the store page for the Student Version of release R2018b.

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