Problems with line plots
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Hi there,
can someone please tell me why my program outputs such a line?
it should look like this:
This is my code:
[u,v] = meshgrid(linspace(-2.5,2.5,40),linspace(-2.5,2.5,40));
x = u-(u.^3/3)+u.*v.^2;
y = -v+(v.^3/3)-v.*u.^2;
z = u.^2-v.^2;
mesh(x,y,z)
hold on
axis equal;
[t,X] = ode45(@Enneper,[0,4*pi],[0,.1,0,.1]);
u = X(:,1);
v = X(:,3);
x = u-(u.^3/3)+u.*v.^2;
y = -v+(v.^3/3)-v.*u.^2;
z = u.^2-v.^2;
plot3(x,y,z,'color','r','LineWidth',1);
function xprime = Enneper(t,x)
xprime = zeros(4,1);
xprime(1) = x(2);
xprime(2) = (2.*x(1).*x(4).^2)/(x(1).^2+x(3).^2+1)-(2.*x(1).*x(2).^2)/(x(1).^2+x(3).^2+1)-(4.*x(3).*x(2).*x(4))/(x(1).^2+x(3).^2+1);
xprime(3) = x(4);
xprime(4) = (2.*x(3).*x(2).^2)/(x(1).^2+x(3).^2+1)-(2.*x(3).*x(4).^2)/(x(1).^2+x(3).^2+1)-(4.*x(1).*x(2).*x(4))/(x(1).^2+x(3).^2+1);
end
Thanks!
回答（1 个）
Cris LaPierre
2020-11-12
0 个投票
You create that line with your plot3 command. If it should be doing what is shown in your other images, you may need to check your equations for x, y, and z.
9 个评论
cheb
2020-11-12
Some quick googling suggests that the lines you desire are created by setting u and v equal to zero.
cheb
2020-11-12
Cris LaPierre
2020-11-12
Worked for me. The image I created is in my post above.
cheb
2020-11-12
Cris LaPierre
2020-11-12
I'll get you started.
- Find your equations for x,y and z at the bottom of your code.
- Change all the u's to 0.
- Run your code.
cheb
2020-11-12
I'm trying that out now. Are the equation for x,y and z at the bottom:
, 
, 
?
cheb
2020-11-12
Cris LaPierre
2020-11-12
I suggest you reread items 1-3. I answer your questions there.
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2020-11-12
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