Index in position 1 is invalid. Array indices must be positive integers or logical values.
1 vue (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Johannes Pommerening
le 2 Juil 2018
Réponse apportée : Abhinav chhabra
le 25 Oct 2021
I got the problem that W is full of NaN's. Error is:
"Index in position 1 is invalid. Array indices must be positive integers or logical values.
Error in Seperationsansatz_2_lin_z (line 16) w(r,t) = W.*T;"
approach A*diff(w,r) + A*r*diff(w,r,r) -B*diff(w,t,t)
rspan = linspace(0,1);
W0 = [0; 1];
[r,W] = ode45(@odefct1,rspan, W0);
tspan = linspace(0,1);
T0 = [0;1];
[t,T] = ode45(@odefct2,tspan,T0);
w(r,t) = W.*T;
% plot(r,W(:,1),'-o',r,W(:,2),'-o')
% title('Solution');
% xlabel('Radius r');
% ylabel('Solution W');
% legend('W_1','W_2')
function dWdr = odefct1(r,W)
E = 70e7;
rho = 2.6989e-4;
ny = 0.34;
K = 1;
A = (0.5-ny);
B = rho*(1-2*ny)*(1+ny)/E;
dWdr = [ W(2); W(1)*(B*K)/A - W(2)/r];
end
function dTdt = odefct2(t,T)
K = 1;
dTdt = [T(2); K*T(1)];
end
0 commentaires
Réponse acceptée
KSSV
le 2 Juil 2018
This line:
w(r,t) = W.*T;
Replace with:
w = W.*T;
2 commentaires
Dinglie Pang
le 18 Déc 2020
Thanks! It works for my error like this! Btw, what's the theory behind it? I just unitentionally type it like "w(r,t)" and didn't see the difference was made, compared with "w"
KSSV
le 18 Déc 2020
When you use w(r,t).. it means w is an array an you are trying to extract indices r,t. To do this your r, t should be positive integers or logical indices. But this is not the case in present. r, t are not indices, so error. You are not supposed to use w(r,t) here.
Plus de réponses (1)
Abhinav chhabra
le 25 Oct 2021
Close matlab and start again. Its weird but worked for me!
all the best
0 commentaires
Voir également
Catégories
En savoir plus sur Ordinary Differential Equations 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!