MATLAB: Find the increasing and decreasing point in array

array

I have an array. Which is increasing. At one point it starts decreases.

This trend starts repeating many times in array. How to find that point in array where the trend starts?

Best Answer

A=[1 2 3 2 1 4 5 6 7 5 2 0 4 5 6 10]
[peaks,idx]=findpeaks(A)

If you haven't a signal processing toolbox

A=[5 2 3 2 1 4 5 6 7 5 2 0 4 5 6 10]
d=sign([0 diff(A)]);
idx=strfind(d,[1,-1])

Related Solutions

MATLAB: The difference in an array

sum(abs(diff([5 3 6 1 5 1 6 7 3])))

MATLAB: How can find a point from an array where the points it follows start to decrease

Assumption : there is on only one decreasing region in your data points.

x = -2:0.1:6;
y = x.^3-5*x.^2+5*x-2;
D = diff(y);
decreaseStart = find(D<0,1,'first');
decreaseEnd = find(D<0,1,'last');
plot(x,y)
hold on 
plot(x(decreaseStart:decreaseEnd),y(decreaseStart:decreaseEnd),'r');

Best Answer

Related Solutions

MATLAB: The difference in an array

MATLAB: How can find a point from an array where the points it follows start to decrease

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