Modify matrix for partial plot
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How can I modify the for loops to create a bracket-shaped domain? In otherwords, I would like to plot everything and omit the first quadrant. Thank you!
clear; close all; clc
n = 40;
x = linspace(0,8,n); dx = x(2)-x(1); y = x; dy = dx;
U = zeros(n);
U(n,1:n/2) =10;
U(n/2,n/2:n-1) =0;
U(1,1:n-1) = 10;
U(2:n,n/2) = 0;
U(1:n/2,n) = 7;
U(n/2:n,n/2) = 0;
alpha=1;
ddt = 1/(4*(1/dx^2+1/dy^2));
for w=1:1000
V = U;
for i = 2:n/2-1
for j = 2:n-1
U(i,j) =ddt*((V(i+1,j)-2*V(i,j)+V(i-1,j))/dx^2+ (V(i,j+1)-V(i,j)+V(i,j-1))/dy^2)+ V(i,j);
end
end
end
figure(1)
contour(y,x,U)
figure(2)
surf(y,x,U)
5 个评论
darova
2020-5-9
Calculate two regions separately
Walter Roberson
2020-5-9
Uc = U;
Uc(1:end/2, 1:end/2) = nan;
figure(1);
contour(y, x, Uc);
figure(2)
surf(y, x, Uc, 'edgecolor', 'none')
Walter Roberson
2020-5-9
surf(y, x, Uc)
The 'edgecolor', 'none' just controls drawing the edges of each face. When you have many faces, the edges start to take over the visual impression, because the edges are constant width even when the faces get small.
Walter Roberson
2020-5-9
x and y are both increasing, and you are using x for rows and y for columns. Which is the "first quadrant" ?
(x=0,y=0) (x=0,y=4) (x=0,y=8)
A B
(x=4,y=0) (x=4,y=4) (x=4,y=8)
C D
(x=8,y=0) (x=8,y=4) (x=8,y=8)
采纳的回答
Here are your bourndary conditions
n = 40;
x = linspace(0,8,n); dx = x(2)-x(1); y = x; dy = dx;
U = zeros(n);
U(n,1:n/2) =10;
U(n/2,n/2:n-1) =0+10;
U(1,1:n-1) = 10;
U(2:n,n/2) = 0+10;
U(1:n/2,n) = 7+3;
U(n/2:n,n/2) = 0+10;
alpha=1;
ddt = 1/(4*(1/dx^2+1/dy^2));
h = imagesc(U);
view(2)
Something is missing
I made some changes to your script. It still doesn't work
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