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# how to find a window of days in a time series data with values in a range

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nlm on 1 May 2020
Closed: MATLAB Answer Bot on 20 Aug 2021
I have a time series data from which I need to find a window of days where the start value is >0.4 and end value is <0.2. However, the values in that window range between 0.4 and 0.2. I have this so far. However, my code is finding all values which have a decreasing trend for 10 days.
AA = data;
s = [0;diff(AA)];
ss = sign(s);
ss(AA<0.4)=-1;
ss= ss';
c = conv2(ss,win , 'valid');
win = ones(1,10)*-1;
p = find(conv2(ss, win, 'valid') == -1);
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nlm on 2 May 2020
Thanks Ameer for taking it up. Please find the data attached.

Ameer Hamza on 2 May 2020
Edited: Ameer Hamza on 2 May 2020
This shows the window of days in which the the value is within the specified range
AA = data.AA;
mask = (0.2 < AA) & (AA < 0.4);
days = find(mask); % contain the days on which the data is in range
ylim([-0.2 1.2])
nlm on 4 May 2020
Thanks!
But this code also considers an increasing trend. What it selected are values which increased from 0.4 to 0.2 and then increased from 0.2 to 0.4. However, I'm looking for all the values where its only shows an decrease from 0.4 to 0.2, and it need not be monotonically decreasing, there can be some increases but it can to be below 0.4.

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