Where have I made mistakes in this code
1 visualizzazione (ultimi 30 giorni)
Mostra commenti meno recenti
Lukgaf
il 22 Mar 2018
Commentato: Walter Roberson
il 22 Mar 2018
%prob2.m
% u’’- 4u’ + 4u = exp(x)+ C;
% Subject to u(1) = 0; u(-1) = 0; C=(-4*exp)/(1+(exp)^2);
N = 40;
[D, x]=cheb(N); %%we call this function to get the Derivative matrix D
I = eye(N+1); % I is the identity matrix of size (N+1)
C=(-4*exp(x))/(1+(exp(x).^2)); %the value of the constant
A = D^2 - 4*D + 4*I; f = exp(x)+ C;
B = A(2:N,2:N); %to impose the boundary conditions
ff = f(2:N);
v = B\ff; %solve the BVP.
u = [0;v;0]; xx = -1:0.1:1;
u_exact = exp(xx)-(sinh(1)/sinh(2))*exp(2*xx)+ C/4;
plot(x,u); %plot the numerical solution
xlabel('x')
ylabel('u')
hold on
plot(xx,u_exact,'o'); % plot the exact solution
hold off
I have used the similar code to solve many questions, why is not working for this? Thanks. It shows this eror: Error
in prob2 (line 11)
v = B\ff; %solve the BVP.
7 Commenti
Risposta accettata
Walter Roberson
il 22 Mar 2018
v = B\ff.'; %solve the BVP.
2 Commenti
Walter Roberson
il 22 Mar 2018
You would get that error if xx is a vector or array and C is a vector or array of different size than xx (though starting in R2016b some size combinations can be meaningfully computed as if you had used bsxfun)
Più risposte (0)
Vedere anche
Categorie
Scopri di più su Linear Algebra in Help Center e File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!