Error when using findpeaks for different limits

Question

Joel 2023-4-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1951038-error-when-using-findpeaks-for-different-limits

评论： Star Strider 2023-4-23

采纳的回答： Star Strider

EFFEKT.mat

在 MATLAB Online 中打开

Hi

I have a script identifying peaks in a curve (EFFEKT). The following part of the script smoothens out the peaks; if there are several peaks close to each other (not going below the limit (Abonnemang) in between), it displays only the biggest.

Abonnemang=24200;
for x=1:99999 %IF THERE IS SEVERAL PEAKS IN A ROW, TAKE THE BIGGEST
    [max_val,locs] = findpeaks(EFFEKT,'MinPeakHeight',Abonnemang,'MinPeakDistance',x); % find the peak and its x axis location
    [t0_pos1,s0_pos1,t0_neg1,s0_neg1]= crossing_V7(EFFEKT,t,Abonnemang,'linear'); % positive (pos) and negative (neg) slope crossing points
    peak_width = t0_neg1- t0_pos1;
    if length(max_val)==length(t0_pos1)
        break
    end
end
 dt = datetime(Q,1,1:1:length(Data{:,1}));
 et = hours(0:23)';
 t = repmat(dt,length(et),1) + repmat(et,1,length(dt));
t=t(:);
figure(3)
plot(t,EFFEKT)
hold on
plot(t,AB)
ylim([-10000 40000])
ylabel('kW')
title('Effektkurva Konsumtion 2021')

My limit was initially set to 24200. I want to check the peaks for the limit 23200, 22200, 21200 and 20200.

24200, 23200 and 22200 works fine, but when I set Abonnemang=21200 I get the following error:

Error using findpeaks

Expected MinPeakDistance to be a scalar with value < 8759.

Error in findpeaks>parse_inputs (line 330)

validateattributes(Pd,{'numeric'},{'real','scalar','nonempty','nonnegative','<',x(M)-x(1)},'findpeaks','MinPeakDistance');

Error in findpeaks (line 135)

= parse_inputs(isInMATLAB,Yin,varargin{:});

Error in FLEX (line 377)

[max_val,locs] = findpeaks(EFFEKT,'MinPeakHeight',Abonnemang,'MinPeakDistance',x); % find the peak and its x axis location

>>

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Image Analyst 2023-4-21

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You forgot to attach your data. If you have any more questions, then attach your data and code to read it in with the paperclip icon after you read this:

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If you just want peaks, or indexes, where your signal is above some threshold, like 24200 then why not just threshold

itsAPeak = signal > threshold;

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Answer 1

Star Strider 2023-4-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1951038-error-when-using-findpeaks-for-different-limits#answer_1220608

在 MATLAB Online 中打开

EFFEKT.mat

The 'MinPeakDistance' value must be less than the number of elements in the vector being used as the first argument to findpeaks. Setting the upper limit on the ‘x’ argument to not exceed that value should avoid that error. Beyond that, ‘t’ does not exist and neither does ‘crossing_v7’ (although I suspect is is a relatively straightforward intersection function using interp1) so this is as far as we can go.

load('EFFEKT.mat')
whos
  Name           Size            Bytes  Class     Attributes

  EFFEKT      8760x1             70080  double              
  ans            1x35               70  char                
  cmdout         1x33               66  char                
% Abonnemang=24200;
Abonnemang=21200;
for x=1:numel(EFFEKT)-1 %IF THERE IS SEVERAL PEAKS IN A ROW, TAKE THE BIGGEST
    [max_val,locs] = findpeaks(EFFEKT,'MinPeakHeight',Abonnemang,'MinPeakDistance',x); % find the peak and its x axis location
    [t0_pos1,s0_pos1,t0_neg1,s0_neg1]= crossing_V7(EFFEKT,t,Abonnemang,'linear'); % positive (pos) and negative (neg) slope crossing points
    peak_width = t0_neg1- t0_pos1;
    if length(max_val)==length(t0_pos1)
        break
    end
end
Unrecognized function or variable 't'.
 dt = datetime(Q,1,1:1:length(Data{:,1}));
 et = hours(0:23)';
 t = repmat(dt,length(et),1) + repmat(et,1,length(dt));
t=t(:);
figure(3)
plot(t,EFFEKT)
hold on
plot(t,AB)
ylim([-10000 40000])
ylabel('kW')
title('Effektkurva Konsumtion 2021')