How to use cumsum function?

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Arif Hoq 2022-9-30

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1814890-how-to-use-cumsum-function

评论： Jan 2022-10-6

采纳的回答： Jan

B.mat

在 MATLAB Online 中打开

not able to get the expected output.

if col5<200 then, col5+25

and the result will be replaced in next row of col5 untill col5 <200.

for example:

B(30,5)=194.87 so, it will be 194.87+25 = 219.87

B(31,5)=219.87 +25 = 244.87

B(32,5)=244.87+25 = 269.87

B(33,5)=269.87+0= 269.87

A=load("B.mat");
B=A.B;
B(:,5)=B(1,4)-cumsum(B(:,3));
CG=25;
for i=1:size(B,1)
    if B(i,5)<200
        B(i,6)=CG;
    else
        B(i,6)=0;
    end
    B(i,7)=B(i,6)+cumsum(B(i,5));
%     B(i,5)=B(i,7);
end

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Jan 2022-9-30

Please avoid pseudo-syntax like "if col5<200 then, col5+25". Use Matlab syntax, because the readers can understand it.

cumsum of a single element replies the value of the element. A cumulative sum is meaningful for a vector only.

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采纳的回答

Jan 2022-10-6

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1814890-how-to-use-cumsum-function#answer_1068000

在 MATLAB Online 中打开

loadValue = [0;50;20;10;5;30;12;8;20;30;5];
capacity  = 300;
mat       = capacity(1,:) - cumsum(loadValue);
for i = 1:numel(loadValue)-1
    if mat(i) < 200
        mat(i) = mat(i) + 25;
    end
    mat(i+1) = mat(i) - loadValue(i+1);
end
mat

更多回答（1 个）

Jan 2022-9-30

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1814890-how-to-use-cumsum-function#answer_1063830

在 MATLAB Online 中打开

CG = 25;
C  = 0;
for i = 1:size(B, 1)
    if B(i, 5) < 200
        if C == 0
           C = CG;
        else
           C = 0;
        end
    end
    B(i, 5) = B(i, 5) + C;
end

or shorter:

CG = 25;
C  = 0;
for i = 1:size(B, 1)
    if B(i, 5) < 200
        C = CG * (C == 0);
    end
    B(i, 5) = B(i, 5) + C;
end

Thank you very much @Jan. you are right, i can omit the cumsum inside the loop. will try to follow your tips on "Load" & "numel / size". that's my expected answer. could you please make it as an answer ?