Selecting non-zero elements from a symbolic vector
4 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Farid Salazar Wong
le 23 Juin 2015
Commenté : Star Strider
le 23 Juin 2015
Given a symbolic vector, say [a*b, 0 , a^2*b*c, 1, 0]. How could I obtain a vector from the non-zero entries, I would like for the given example to have [a*b, a^2*b*c, 1] as a result. I tried nonzeros but this does not work for type sym.
1 commentaire
Walter Roberson
le 23 Juin 2015
Do you want to remove the entries that are identical to 0, or the entries that can be proven to be 0? For example if one of the entries was 1 - cos(theta)^2 - sin(theta)^2 then we could show that this must be 0 (at least for finite non-nan values), so should it be removed?
Réponse acceptée
Star Strider
le 23 Juin 2015
This works for me (in R2015a):
syms a b c
V = [a*b, 0 , a^2*b*c, 1, 0];
Vnz = V(V~=0)
Vnz =
[ a*b, a^2*b*c, 1]
2 commentaires
Plus de réponses (2)
Mischa Kim
le 23 Juin 2015
Farid, you could use
syms a b c d = [a*b, 0 , a^2*b*c, 1, 0]; d(d==0) = [] d = [ a*b, a^2*b*c, 1]
2 commentaires
Mischa Kim
le 23 Juin 2015
Then you need to post the entire code. Use the paper clip symbol to attach.
Azzi Abdelmalek
le 23 Juin 2015
Modifié(e) : Azzi Abdelmalek
le 23 Juin 2015
syms a b c
d = [a*b, 0 , a^2*b*c, 1, 0]
c=nonzeros(d).'
2 commentaires
Voir également
Catégories
En savoir plus sur Conversion Between Symbolic and Numeric 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!