# How to find the latest peak value of a curve.

1 view (last 30 days)
Jean-Baptiste DUCAT on 13 Dec 2016
Hello,
I have a problem, i want to find the latest peak value of the following power curve. It is not the maximum power point, i've already found it earlier. But i should compare the latest value P(end) with P(end-1) and if P(end)<P(end-1) we should continue like this... to reach the point where P(i)>P(i-1) to come one value before, it will give me the latest peak power value.
Thank's for your help ;) Jb
##### 2 CommentsShow NoneHide None
Jean-Baptiste DUCAT on 13 Dec 2016
I've tried with findpeak function but it return me an error message:
>> PV=plot(U,P)
PV =
Line with properties:
Color: [0 0.4470 0.7410]
LineStyle: '-'
LineWidth: 0.5000
Marker: 'none'
MarkerSize: 6
MarkerFaceColor: 'none'
XData: [1x262 double]
YData: [1x262 double]
ZData: [1x0 double]
Show all properties
>> findpeaks(PV)
Error using findpeaks
Expected Y to be one of these types:
numeric
Instead its type was matlab.graphics.chart.primitive.Line.
Error in findpeaks>parse_inputs (line 191)
validateattributes(Yin,{'numeric'},{'nonempty','real','vector'},...
Error in findpeaks (line 134)
= parse_inputs(Yin,varargin{:});
Jiro Doke on 13 Dec 2016
findpeaks takes a numeric vector as the input. That's what the error "Expected Y to be numeric" means.

Sign in to comment.

### Accepted Answer

Jiro Doke on 13 Dec 2016
[pk,loc] = findpeaks(P(end:-1:1),'NPeaks',1);
[U(end-loc+1) pk]
##### 1 CommentShow -1 older commentsHide -1 older comments
Jean-Baptiste DUCAT on 13 Dec 2016
It's exactely that thank's !! ;)

Sign in to comment.

### More Answers (1)

Adam on 13 Dec 2016
If you have the Signal Processing Toolbox just use findpeaks, if not since you only want the last peak even a simple loop running from the end of the trace forward and stopping when you reach a point where you stop increasing would do the job.
##### 1 CommentShow -1 older commentsHide -1 older comments
Jean-Baptiste DUCAT on 13 Dec 2016
I've already done that but it's ok i've the right answer now thank's for all ;)

Sign in to comment.

### Categories

Find more on Descriptive Statistics in Help Center and File Exchange

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!