Indexing array of symbolic variables dependent on time
16 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
I need to create variable number of symbolic variables and access each of them individually. It is necessary that they are time varying for purposes of calling diff.
So far I can see that a variable number can be created by
N = 5 % number of variables for example
syms x(t) [1,N]
But if one then tries to access the first element, x1(t), this results in
>> x(1)
ans =
[ x1(1), x2(1)]
0 commentaires
Réponses (1)
Walter Roberson
le 16 Juil 2020
you cannot do that with the symbolic toolbox. The () indexing is incompatible between symfun and arrays.
If you need an array of symfun then it must be cell array.
2 commentaires
Walter Roberson
le 16 Juil 2020
x = str2sym(compose("x" + (1:4) + "(t)"))
This will be an array of symbols that live at the MuPAD level, and can be operated like
dsolve(diff(x(1),t) == t^2)
but they will not act like symbolic functions. For example if you had done
syms y(t)
then you could use y(0) to represent y evaluated at 0, but you cannot use x(1)(0) and would instead need to use subs(x(1),t,0)
Voir également
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!