Remove Dashed Grey Asymptote Lines From Plot

I have a plot of a few symbolic functions in matlab, and I'm getting some grey dashed lines. I'm going to guess that these are for asymptotes, which I expected. Is there a way to remove these lines?

Attached is my plot. The lines I'm talking about are at x = 4 and x = 0. Ignore the legend and other colors, that's another story.

[Walter Roberson]

is this fplot or fimplicit?

dashed lines for fplot are discontinuities not asymptopes

[Benjamin Blood]

I used fplot. I guess you're right, it's a discontinuity. Do you know if there's a way to remove it?

[mauricio]

is there a way to change their color?

Answer 1

[Walter Roberson]

If you let

h = fplot(expression, range)

then

h.NodeChildren(1).Visible = 'off';

will turn off the discontinuinity lines. (The gray dashed ones, at least. At the moment I do not recall the formula for any functions that generate the brown discontinuity lines. Possibly NodeChildren(2) for those.)

[Benjamin Blood]

Hi there, sorry for the delay in letting know if this worked. I wasn't able to hide the grey line. I tried turning off the visibility on all the node children, and it got rid of everything except the grey line.

[Walter Roberson]

can you attach your actual code?

[Benjamin Blood]

Sure. Here it is. I've changed it a bit since I first asked the question, the new plot is attached. As I've commented in the code, g(1) is the only symbolic function I'm currently trying to plot.

%% Standard Housekeeping
clear all;
close all;
clc;

%% Define objective functions and constraints
syms x1 x2 f1(x1, x2) f2(x1, x2)

% Defining two objective functions
f1(x1, x2) = -0.4 * x1^2 - 4 * x1 - exp(x2^2);
f2(x1, x2) = -(x2 - 5.1/(4*pi^2) * x1^2 + 5/pi * x1 - 6)^2 - 10 * (1 - 1/(8*pi)) * cos(x1) - 10;

% Defining design constraints
g(1) = 2.5 * x1^2 + 0.5 * x1 * x2 - 3; % Only one I'm currently plotting
g(2) = -4 * x1 + 8 * x2^2 - 16;
g(3) = 6 * x1^2 + 2 * x2^2 + 8 * x1 * x2 - 2.5 *x1 - 4 * x2 - 12;

% Defining side cosntraints
x1L = -1.5;
x1U = 2;

x2L = -2;
x2U = 1;

%% Plotting constraints
hold on;
    % Plotting g(1)
    consPlot = fplot(solve(g(1), x2), [-10 10]);
    consPlot.NodeChildren(1).Visible = 'off';
hold off;

And here is the resulting plot:

[Walter Roberson]

Put a drawnow() before setting the Visible to off. If you set the visible to off before the drawnow then it will be reset to on when the plot renders.

... No, I do not know why this happens. I could make some guesses.

Oh, look at that, the line comes back again if you resize the plot. I think we can deduce that the rendering callbacks are turning the visibility on. You might want to add in a ResizeFcn callback to drawnow() and turn it invisible again after the axes changes. Or perhaps a PostSet listener on the axes Position property.

[Benjamin Blood]

Running drawnow works. Right now I'm just running those commands in the command window every time I resize the plot, but that works for now. Thank you for your help!