How to plot all contour lines in one plot?

5 次查看（过去 30 天）
Jorge Arturo Clares Pastrana
评论： Star Strider 2022-3-15
Giiven a function f(x) I need to Plot the level sets contour lines where 𝑓(x) = −4.34, −4.3, −4.2, −4.1, −4, −3, −2, −1, 0.
Plot all of them in one graph

请先登录，再回答此问题。

采纳的回答

Star Strider
Star Strider 2022-3-15
Ran in:
Specify them as a single levels vector —
[X, Y, Z] = peaks(50);
figure
contour(X, Y, Z, [-4.34, -4.3, -4.2, -4.1, -4, -3, -2, -1, 0], 'ShowText',1)
colormap(turbo)
.
  2 个评论
Jorge Arturo Clares Pastrana
Jorge Arturo Clares Pastrana 2022-3-15
Thnakyou.
z = -4*x - 2*y - x^2 + 2*x^4 - 2*x*y + 3*y^2;
when i input the following equation for z it outputs a blank post do you know why?
Star Strider
Star Strider 2022-3-15
Ran in:
First, the function needs to be vectorised so that it can do element-wise calculations. Otherwise, it could be because for the values of ‘x’ and ‘y’ you are using, ‘z’ has no values in the range of the desired contours. Also, ‘x’ and ‘y’ must be matrices, not vectors, although I suspect that would throw a specific error.
Use your values for ‘x’ and ‘y’ in something like this example code —
z = @(x,y) -4*x - 2*y - x.^2 + 2*x.^4 - 2*x.*y + 3*y.^2; % Vectorised Anonymous Function For 'z'
x = linspace(-5, 5, 150);
y = linspace(-5, 5, 150);
[X,Y] = ndgrid(x, y);
Z = z(X,Y);
figure
contour(X, Y, Z, [-4.34, -4.3, -4.2, -4.1, -4, -3, -2, -1, 0], 'ShowText',1)
colormap(turbo)
axis([-1 2 -1 2])
.

请先登录，再进行评论。

更多回答（1 个）

Jorge Arturo Clares Pastrana
Thnakyou.
z = -4*x - 2*y - x^2 + 2*x^4 - 2*x*y + 3*y^2;
when i input the following equation for z it outputs a blank post do you know why?

类别

在 Help Center 和 File Exchange 中查找有关 Contour Plots 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by