Index in position 1 is invalid. Array indices must be positive integers or logical values.
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Johannes Pommerening
am 2 Jul. 2018
Beantwortet: Abhinav chhabra
am 25 Okt. 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
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Akzeptierte Antwort
KSSV
am 2 Jul. 2018
This line:
w(r,t) = W.*T;
Replace with:
w = W.*T;
2 Kommentare
Dinglie Pang
am 18 Dez. 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
am 18 Dez. 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.
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Abhinav chhabra
am 25 Okt. 2021
Close matlab and start again. Its weird but worked for me!
all the best
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