Calculating area under curve with cutoff
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I got a n-by-1 row vector obtained by measured data with n likely beeing about 100.000. The values can be either positive or negative and are derived as the difference from 2 other functions:
I calculated the area with cumtrapz / cumsum (red line):
The value of the cumulated area under the curve should display a state which can not be negative. Therefore, I want to lift up the curve in the upper graph in the consecutive negativ intervals, so it looks like the blue line. To get there i used this code:
if dv(a)>0 && dv(a+1)<=0
This code works for me, but it is not very economic. I would like to avoid the for loop and use a faster vectorized solution because of speed. The function is going to be called about thousand times or even more often with vectors about 100k. Could you help me to find a more convenient way for calculation?
A possible solution could seek for consecutive local minima (tn). Detect the first point following after the local minimum which is equal (pn) and then create a stepwise mixed function which looks similar to this one: