Gradient of a 2D plot
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I have a 2D plot of potential (V) (circular contour plot). I have to find the electric field (E) by taking the gradient. How is it possible to see the gradient of V. [U,W]=gradient(V) returns the gradient in X and Y direction and quiver(X,Y,U,W) helps to visualize the vector field. How is it possible to view effective gradient. Contour (X,Y,U) will only help me to see gradient in x direction. How can I see the effect of gradient which is a vector sum of both gradient in X and Y.?
2 个评论
Ameer Hamza
2020-9-30
What is wrong with quiver. It generates arrows in the gradient direction.
Prince Alex
2020-9-30
采纳的回答
Star Strider
2020-9-30
0 个投票
See the gradient documentation section on Contour Plot of Vector Field . It demonstrates exactly what you are describing.
4 个评论
Prince Alex
2020-9-30
Star Strider
2020-9-30
I am not certain what you want.
This uses the example from the gradient documentation to create the gradient vectors, and contourf to plot their sum:
x = -2:0.2:2;
y = x';
z = x .* exp(-x.^2 - y.^2);
[px,py] = gradient(z);
figure
contourf(px+py)
figure
meshc(px+py)
The meshc plot simply gives another view of the result to clarify it.
Prince Alex
2020-9-30
Star Strider
2020-9-30
My pleasure!
It should not be showing any error. It is an example from the documentation (that I linked to in my oridginal Answer), and ran for me without error in R2020b. The ‘px’ and ‘py’ matrices are both (21x21), so the addition should work. If it is not working with your code, please post it.
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