Surf from a numerical array
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Suppose I solve a PDE and obtain a solution in 2D say . If I do surf(u) I get a picture of the whole thing. Can I change the values of the axis to correspond to the actual values of interest? Currently the axis values just represent the number of data points, so I want to change that to actual values of interest.
采纳的回答
Yes. You can use the xlim and ylim functions to set the axes limits to the actual region of interest.
Example:
% some matrix
z = peaks(100);
% the whole thing
figure();
surf(z)
xlabel('x')
ylabel('y')
zlabel('z')
% the actual region of interest
figure();
surf(z)
xlabel('x')
ylabel('y')
zlabel('z')
xlim([30 75])
ylim([50 90])
7 个评论
Mat Hunt
2024-2-26
Voss
2024-2-26
Hmm. It appears not to disappear in the code I ran above. Maybe you've chosen some xlim and/or ylim that are outside the limits of the surface.
Mat Hunt
2024-2-26
Voss
2024-2-26
"It appears that you [h]ave misunderstood my question."
Entirely likely.
"The labels that you get when you just do surf(array) is the number of entries. I want to relabel these to actual physical values."
Thank you for clarifying.
In that case, specify the x and y vectors/matrices in the call to surf. Something like
surf(t,x,u)
or
surf(x,t,u)
depending on the orientation of u with respect to t and x.
Mat Hunt
2024-2-26
Voss
2024-2-26
Not necessarily. In surf(X,Y,Z) X and Y can be vectors or matrices.
meshgrid would be useful for constructing matrix X and Y from vector X and Y, but you can use the vectors directly in surf.
"Currently the axis values just represent the number of data points, so I want to change that to actual values of interest."
Specify the values of interest in the call to surf.
Example:
% 10 t values ranging from 0.01 to 0.02
t = linspace(0.01,0.02,10)
% 15 x values ranging from 100 to 200
x = linspace(100,200,15)
% 15-by-10 matrix u
u = exp(t.*x.')
% plot the surface
surf(t,x,u)
xlabel('t')
ylabel('x')
zlabel('u')
更多回答（1 个）
Sufiyan
2024-2-26
0 个投票
I believe this is similar to changing the limits on the axis scale to different values or rescaling the axis.
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