problem with plotting a 1D graph

4 次查看（过去 30 天）
Yamina chbak
Yamina chbak 2020-12-1
评论： Yamina chbak 2020-12-3
Hi,
I have solved a 2D time problem U(x,y,t), 0<=x,y<=L and 0<=t<=T, by FEM and i get
trisurf(TRI,x,y,U(:,N)) % N number of time steps
% TRI triangle for create mesh
My question is how to write Matab code to see plot 1D for U solution of this problem if I choose for example : U(5,6,t) for all 0<=t<=T and U(x,5,0.15) for 0<=x<=L.
(To simulate 1D problem through a 2D problem ) this what i try write plot but it is not correct
% plot of time : U(5,6,t)
t=linspace(0,2,0.15);
for i=1:np % np number of nodes
find(x(m)==5 & y(m)==6)
end
plot(t,U(:,t))
%%%%%%%%%%%%%
% plot of x : U(x,5,0.15)
t=0.15;
for i=1:np % np numbers of nodes
find(y(m)==5
end
plot(x,U(:,t)
Please i need help
Thanks

请先登录，再回答此问题。

回答（1 个）

Stephan
Stephan 2020-12-2
编辑：Stephan 2020-12-2
You dont save the results of find anywhere - try:
% plot of time : U(5,6,t)
t=linspace(0,2,0.15);
for i=1:np % np number of nodes
U(i,:) = find(x(m)==5 & y(m)==6)
end
plot(t,U)
  1 个评论
Yamina chbak
Yamina chbak 2020-12-3
Thanks @Stephan for answer my question, but i think i give you my mistaken information.
Look my code what i did it for solving 2d problem and see plot2D :
% i have a list of Nodes
x=Nodes(:,2); y=Nodes(:,3);
np=size(x,1); %number of nodes
T=1;N=21; dt=T/N-1;
for k=1:N
t(k)=(k-1)*dt;
L(:,k+1)=g(x,y,t(k+1)) % a simple function dependant time
b(:)=M+L(:,k+1); % M is a matrix
% solver problem
U(:,k+1)=A\b(:);
end
% Resultat
figure()
trisurf(TRI,x,y,U(:,N))
What I want is to see plot 1D of U(x,pi/2,0.15) solution of this problem with choosing value y=pi/2 and t=0.15 :
plot(x,????)
I apologize for any difficultes that and please help me if you have time
Thanks

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Surface and Mesh Plots 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by