同时等高线和 3d 图

Question

我试图在 Julia 中同时绘制函数的等高线和曲面，但我似乎找不到方法。

有没有简单的方法可以做到这一点？

Answer 1

这是我为 Plots 设计的一个例子。 PyPlot 包有更好的东西，可以用 Makie 做一些事情：

import Contour: contours, levels, level, lines, coordinates

function surface_contour(xs, ys, f; offset=0)
  p = surface(xs, ys, f, legend=false, fillalpha=0.5)

  ## we add to the graphic p, then plot
  zs = [f(x,y) for x in xs, y in ys]  # reverse order for use with Contour package
  for cl in levels(contours(xs, ys, zs))
    lvl = level(cl) # the z-value of this contour level
    for line in lines(cl)
        _xs, _ys = coordinates(line) # coordinates of this line segment
        _zs = offset .+ 0 .* _xs
        plot!(p, _xs, _ys, _zs, alpha=0.5)        # add curve on x-y plane
    end
  end
  p
end

xs = ys = range(-pi, stop=pi, length=100)
f(x,y) = 2 + sin(x) - cos(y)

surface_contour(xs, ys, f)

同时等高线和 3d 图

Simultaneous Contour and 3d Plot

plot

contour

julia