Standard Deviation of 3D matrix with NaN elements

4 vues (au cours des 30 derniers jours)
António Rouxinol Fragoso
António Rouxinol Fragoso le 17 Sep 2019
Commenté : Rik le 17 Sep 2019
I have a 3D matrix of size (170 x 170 x 27). Some of the entries are NaN, zero and the rest have real values.
I would like to obtain the standard deviation of this matrix, excluding the NaNs. I have tryed several commands, but I haven't been able to get this to work.
Could you help me?
Thank you in advance,
Antonio :)

Réponses (2)

Johannes Fischer
Johannes Fischer le 17 Sep 2019
As described in the doumentation for std, there is a flag on how to deal with 'NaN' values. If you want the standard deviation of all values, excluding the NaNs, then write
% dummy matrix
m=rand(170, 170, 27);
m(m>0.9) = NaN;
sdev = std(m, 0, 'all', 'omitnan')
  4 commentaires
António Rouxinol Fragoso
António Rouxinol Fragoso le 17 Sep 2019
I'm using R2018a.
Rik
Rik le 17 Sep 2019
The 'all' syntax was introduced in R2018b, so you'll have to linearize your array like I describe in my answer. doc for R2018a, doc for R2018b

Connectez-vous pour commenter.


Rik
Rik le 17 Sep 2019
This syntax should work for most releases:
sdev=std(m(:),'omitnan');

Catégories

En savoir plus sur Logical dans Help Center et File Exchange

Community Treasure Hunt

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

Start Hunting!

Translated by