Can someone please check my code?

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Joseph Alcena
Joseph Alcena 2023-5-8
评论： Cris LaPierre 2023-5-8
Ran in:
I'm trying to plot the wave equation in 3D but I'm getting an error with the array size for e.
This is the error it's giving me:
"Arrays have incompatible sizes for this operation. Error in PHYS225_Project (line 36) e = sin(w.*t.*z);"
If anyone can help me make my code work I'f greatly appreicate it.
Here's my code:
clear all
clc
close all
% Define the parameters
xo = 1;
yo = 1;
v = 5;
Lx = 50;
Ly = 50;
n = 0:1:10;
m = 0:1:10;
% Compute the wave vector and frequency
[kx, ky] = meshgrid(n*pi/Lx, m*pi/Ly);
w = v * sqrt(kx.^2 + ky.^2);
% Define the time and space grids
t = 0:0.5:10;
z = 0:0.5:10;
[x, y] = meshgrid(0:Lx/50:Lx, 0:Ly/50:Ly);
% Compute the wave equation solution
a = sin(n*pi*xo/Lx);
b = sin(m*pi*yo/Ly);
a_mat = repmat(a.', [1, length(m)]);
b_mat = repmat(b, [length(n), 1]);
% c = sin(kx.*x);
c = sin(reshape(x,1,[]).'*kx(:).');
% d = sin(ky.*y);
d = sin(reshape(y,1,[]).'*ky(:).');
w
w = 11×11
0 0.3142 0.6283 0.9425 1.2566 1.5708 1.8850 2.1991 2.5133 2.8274 3.1416 0.3142 0.4443 0.7025 0.9935 1.2953 1.6019 1.9110 2.2214 2.5328 2.8448 3.1573 0.6283 0.7025 0.8886 1.1327 1.4050 1.6918 1.9869 2.2871 2.5906 2.8964 3.2038 0.9425 0.9935 1.1327 1.3329 1.5708 1.8318 2.1074 2.3926 2.6842 2.9804 3.2799 1.2566 1.2953 1.4050 1.5708 1.7772 2.0116 2.2654 2.5328 2.8099 3.0941 3.3836 1.5708 1.6019 1.6918 1.8318 2.0116 2.2214 2.4537 2.7025 2.9638 3.2345 3.5124 1.8850 1.9110 1.9869 2.1074 2.2654 2.4537 2.6657 2.8964 3.1416 3.3982 3.6637 2.1991 2.2214 2.2871 2.3926 2.5328 2.7025 2.8964 3.1100 3.3396 3.5820 3.8348 2.5133 2.5328 2.5906 2.6842 2.8099 2.9638 3.1416 3.3396 3.5543 3.7830 4.0232 2.8274 2.8448 2.8964 2.9804 3.0941 3.2345 3.3982 3.5820 3.7830 3.9986 4.2266
t
t = 1×21
0 0.5000 1.0000 1.5000 2.0000 2.5000 3.0000 3.5000 4.0000 4.5000 5.0000 5.5000 6.0000 6.5000 7.0000 7.5000 8.0000 8.5000 9.0000 9.5000 10.0000
z
z = 1×21
0 0.5000 1.0000 1.5000 2.0000 2.5000 3.0000 3.5000 4.0000 4.5000 5.0000 5.5000 6.0000 6.5000 7.0000 7.5000 8.0000 8.5000 9.0000 9.5000 10.0000
e = sin(w.*t.*z);
Arrays have incompatible sizes for this operation.
u = a_mat.*b_mat.*c.*d.*e;
% Plot the solution
figure(1);
subplot(211);
surf(x, y, u(:, :, 1));
xlabel('x');
ylabel('y');
zlabel('u');
title('Wave equation solution at t = 0');
axis([0 Lx 0 Ly -1 1]);
colormap(jet);
subplot(212);
surf(x, y, u(:, :, end));
xlabel('x');
ylabel('y');
zlabel('u');
title(['Wave equation solution at t = ' num2str(t(end))]);
axis([0 Lx 0 Ly -1 1]);
colormap(jet);

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回答（1 个）

Cris LaPierre
Cris LaPierre 2023-5-8
I've edited your code to make the error more visible.
Can you now see why w.*t.*z is giving your an error that the arrays contain incompatible size for this operation?
  2 个评论
Joseph Alcena
Joseph Alcena 2023-5-8
I see why now. Any suggestions on how I can make the w matrix the same as t and z?
Cris LaPierre
Cris LaPierre 2023-5-8
Since you ultimately want to use surf to visualize your data, I would think the best approach is to make them all 11x11, but you would know better than me if that is correct.

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