To calculate the area under a series of curves

Question

Vahid Esmaeili 2020-7-28

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/571774-to-calculate-the-area-under-a-series-of-curves

评论： Star Strider 2020-7-29

Hello,

Would you please assist me to calculate the area under different sections of the curves of FR2_.mat? The sections are IC, LR, MS, TS, PS, P50, TOR.

The following lines calculate different sections of the curve like the photo attached to the question.

cycl=13;
for i=1:length(cycl)
    if length(i+5)>length(FR2_)
        break
    end
    LR(i)=find(FR2_(i,:)==max(FR2_(i,1:40)));
   
    for j= LR:70
        if FR2_(i,j+1)> FR2_(i,j)
          MS(i)= find(FR2_(i,:)==( FR2_(i,j)));
        end
        
    end
end 
for i=1:length(cycl)
   
IC(i)=find(FR2_(i,:)==min(FR2_(i,1:3)));
LR(i)=find(FR2_(i,:)==max(FR2_(i,1:40)));
TS(i)=find(FR2_(i,:)==max(FR2_(i,MS(i):85)));
PS(i)=find(FR2_(i,:)==max(FR2_(i,TS(i):99)));
P50(i)=find(FR2_(i,:)==min(FR2_(i,49:51)));
TOR(i)=find(FR2_(i,:)==min(FR2_(i,97:99)));
end

Also, there is a FL2_.mat. I have to find the points of FL2_.mat the correspond to the "IC, LR, MS, TS, PS, P50, TOR" points of FR2_. Then, I have to calculate area under these sections as well.

I appreciate your attention to this question.

Vahid,

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Answer 1

Star Strider 2020-7-28

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/571774-to-calculate-the-area-under-a-series-of-curves#answer_472015

在 MATLAB Online 中打开

First, the for loops should both be:

for i = 1:cycl

The areas calculation appears to be straightforward:

for i=1:cycl
AUC = cumtrapz(FR2_(i,:));
IC(i)=find(FR2_(i,:)==min(FR2_(i,1:3)));
LR(i)=find(FR2_(i,:)==max(FR2_(i,1:40)));
TS(i)=find(FR2_(i,:)==max(FR2_(i,MS(i):85)));
PS(i)=find(FR2_(i,:)==max(FR2_(i,TS(i):99)));
P50(i)=find(FR2_(i,:)==min(FR2_(i,49:51)));
TOR(i)=find(FR2_(i,:)==min(FR2_(i,97:99)));
Areas(i,:) = diff(AUC([IC(i) LR(i) TS(i) PS(i) P50(i) TOR(i)]));
end