Area between two curves
1 view (last 30 days)
Show older comments
Christian Reece
on 23 Apr 2015
Answered: Star Strider
on 23 Apr 2015
I was wondering if there was a simpler/faster way of calculating the area between the two curves at each point (both of which are normailsed so the total area is 1). I am currently using a simple for loop to get the area between each set of points for the two curves, then subtracting it to get the difference i.e.
for i = 1:length(normpeak)-1
resN(i) = trapz(time(i:i+1),peak1(i:i+1));
resF(i) = trapz(time(i:i+1),peak2(i:i+1));
end
res = resN-resF;
This works, but unfortunately it is very slow. I was reading up on the trapz function and from what I understood it calculates the total integral by performing something very similar to what i'm doing now (see image) but sums the data at the end.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/149358/image.png)
Is there a way to stop trapz from performing this summing of the data, so I can speed up my code?
0 Comments
Accepted Answer
Star Strider
on 23 Apr 2015
I don’t have your data so I can’t test it, but this approach could work:
res = cumtrapz(time, peak1) - cumtrapz(time, peak2);
0 Comments
More Answers (1)
Binbin Qi
on 23 Apr 2015
if you can get the points of every curve, you can use polyarea function to get the area, and then diff
See Also
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!