清空筛选条件
清空筛选条件

how "fplot" works?

8 次查看（过去 30 天）
Luigi Stragapede
Luigi Stragapede 2020-5-18
评论： dpb 2020-5-18
I have a function which depends on a particular variable, that is T(theta) where the variable is theta. Then, I plotted the function T(theta) with "fplot".
I want to know: which is the frequency of theta with which the fuction T is plotted? I suppose that Matlab consider a lot of theta and compute T for each of these theta.
  1 个评论
dpb
dpb 2020-5-18
Just read the documentation...
fplot(f) plots the curve defined by the function y = f(x) over the default interval [-5 5] for x.
It sets the number of points internally; not sure the heuristics it uses but the difference in x-values over a default range isn't identical so it's not just linspace(x1,x2,N). But,it's not trivially obvious just where the algorithm is buried in a very quick look at the m-file.
A trivial plot returned 57 for the number of points in X|YData arrays....interesting choice...

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Ameer Hamza
Ameer Hamza 2020-5-18
编辑：Ameer Hamza 2020-5-18
fplot does not use fixed mesh spacing. It adaptively calculates the distance between mesh points (probably using derivates) of the function. See the parameter MeshDensity: https://www.mathworks.com/help/releases/R2020a/matlab/ref/fplot.html#bu6xntj-1_sep_shared-MeshDensity. By default, it is 23, but MATLAB usually uses a higher number of points for a smoother curve. The algorithm to adaptively calculate the mesh point is not provided, but you can find out the x-values and y-values of points using the following statements
syms x
y = x.^2*sin(x);
f = fplot(y)
f.XData
f.YData
  1 个评论
Walter Roberson
Walter Roberson 2020-5-18
Furthermore, fplot has code to attempt to find discontinuities even if they are at a finer spacing than the adaptive mesh would suggest.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Surface and Mesh 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