Returning peak values from a column

1 vue (au cours des 30 derniers jours)
Christopher
Christopher le 8 Sep 2013
Hello,
I am trying to do the following. I have two column vectors:
Cp=[0;0.4;0.8;0.99;0.8;0.4;0];
Cf=[1;2;3;4;5;6;7];
I am trying to obtain a Cf column vector for the corresponding Cp column vector peak and below. So Cp peaks at 0.99 and I am trying to obtain the values for Cf from the beginning of Cp until the peak of Cp. All of the values of Cp are less than the peak value.
So
Cf_new=[1;2;3;4]
I am also trying to obtain the last half of Cf for Cp after the peak until the end. So the last half would be:
Cf_new2=[5;6;7]
Thank you

Réponse acceptée

Matt J
Matt J le 8 Sep 2013
[~,idx]=max(Cp);
Cf_new=Cf(1:idx);
Cf_new2=Cf(idx+1:end);

Plus de réponses (2)

Image Analyst
Image Analyst le 8 Sep 2013
Modifié(e) : Image Analyst le 8 Sep 2013
peakIndex = find(diff(Cp) < 0, 1, 'first')
Cf_new = Cf(1 : peakIndex)
Cf_new2 = Cf(peakIndex+1:end)
In the command window:
peakIndex =
4
Cf_new =
1
2
3
4
Cf_new2 =
5
6
7
Or you might mean "max value" instead of peak. In that case you need to use max() instead of diff(), and you need to know what you want to do if you have a run of several max values in a row.
  1 commentaire
Christopher
Christopher le 8 Sep 2013
Thanks Image Analyst

Connectez-vous pour commenter.


Andrei Bobrov
Andrei Bobrov le 8 Sep 2013
Modifié(e) : Andrei Bobrov le 8 Sep 2013
t = [true;diff(Cp(:))>=0]
Cf_new = Cf(t);
Cf_new2 = Cf(~t);

Community Treasure Hunt

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

Start Hunting!

Translated by