Error: Children may only be set to a permutation of itself

When I use the following commands in a subplot environment

getChildren = get(gca,'Children');
set(gca,'Children',[getChildren(4:5); getChildren(1:3)]) % I use this command to reshuffle the several objects in my plot (similarly to uistak)   

Things work in the first subplot, i.e. suplot(1,2,1). But, when Matlab goes to the second subplot, i.e. subplot(1,2,2), it is not able to produce my graphics and gives me the following error:

Error using matlab.graphics.axis.Axes/set
Children may only be set to a permutation of itself.

Error in MyFile (line 215)
set(gca,'Children',[getChildren(4:5); getChildren(1:3)])

Do you have any suggestion to avoid/solve this error?

Here following a simplified code:

% Graph
s = [1 1 1 3 3 6 7 8 9  10  4 12 13  5 15 16 17 18 19 19 20 20 17 24 25  4 27 28 29];
t = [2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30];
G = graph(s,t);
% Node ID:   1 2 3 4 5 6 7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
G.Nodes.X = [2 1 3 2 4 4 5  4  5  4  5  1  3  3  5  6  7  6  8  7  9  8  9  8  9 10  1  1  0  1]'; 
G.Nodes.Y = [2 1 3 9 3 5 8 12 13 18 21 15 18 21  0  2  8 12 15 20 10 22 18  5  4  4  5  8 12 23]';

% Subgraphs
Gpath{1} = subgraph(G,shortestpath(G,4,14));
Gpath{2} = subgraph(G,shortestpath(G,4,26));
Gpath{3} = subgraph(G,shortestpath(G,4,30));
Gpath{4} = subgraph(G,shortestpath(G,3,10));
Gpath{5} = subgraph(G,shortestpath(G,3,28));
Gpath{6} = subgraph(G,shortestpath(G,3,21));
Gpath{7} = subgraph(G,shortestpath(G,17,12));
Gpath{8} = subgraph(G,shortestpath(G,17,23));
Gpath{9} = subgraph(G,shortestpath(G,17,26));

% Figure
for k = 1 : 2
    subplot(3,2,k);
    hold on
    p(1) = plot(G,'XData',G.Nodes.X,'YData',G.Nodes.Y,'LineWidth',1,'EdgeColor','k','NodeColor','k');
    for i = [1 2 3]
        p(2) = plot(Gpath{i},'XData',Gpath{i}.Nodes.X,'YData',Gpath{i}.Nodes.Y,'EdgeColor','y','NodeColor','y');
        p(2).NodeLabel = {};
        p(2).EdgeAlpha = 1;
        p(2).LineWidth = 5;
        % p(2).DisplayName = 'Banana';
    end
    for i = [7 8 9]
        p(3) = plot(Gpath{i},'XData',Gpath{i}.Nodes.X,'YData',Gpath{i}.Nodes.Y,'EdgeColor','g','NodeColor','g');
        p(3).NodeLabel = {};
        p(3).EdgeAlpha = 1;
        p(3).LineWidth = 9;
        p(3).DisplayName = 'Apple';
    end
    for i = [4 5 6]
        p(4) = plot(Gpath{i},'XData',Gpath{i}.Nodes.X,'YData',Gpath{i}.Nodes.Y,'EdgeColor','r','NodeColor','r');
        p(4).NodeLabel = {};
        p(4).EdgeAlpha = 1;
        p(4).LineWidth = 15;
        p(4).DisplayName = 'Strawberry';
    end
    text(8,.2,'hello')
    plot([0.5 0.6],[0 6],'color',[0.6 0.6 0.6],'LineWidth',5);
    rectangle('Position',[7,1,2,0.5],'FaceColor',[0.4 0.4 0.4]);


    a = get(gca,'Children');
    b = findobj('Type','GraphPlot');
    idx1 = find(~cellfun(@isempty,{b.DisplayName})); % GraphPlots with name
    idx2 = find(cellfun(@isempty,{b.DisplayName}));  % GraphPlots without name
    c = vertcat(flipud(b(idx2)),flipud(b(idx1)));
    set(gca,'Children',[c; setdiff(a,b)])
    legend(c)

end

Error using matlab.graphics.axis.Axes/set
Children may only be set to a permutation of itself.

% The error that I get in my machine with the above mentioned code:
Error using matlab.graphics.axis.Axes/set
Children may only be set to a permutation of itself.

Error in uistack_graph_subgraph_2 (line 61)
    set(gca,'Children',[c; setdiff(a,b)])

[Ganesh]

Could you please share the entire code you are using?

[Sim]

Thanks for the comment @Ganesh, code added :-)

The code I added here is similar to that one I posted in another question and answer.

Answer 1

[Steven Lord]

In programmatic code, ideally you should use a specific axes handle rather than trusting that gca returns the axes you think it does. [If your user were to click on a different axes to select it, for example, that would make it the current axes even if you last plotted in a different one.] In your example, either call subplot with an output argument (so it returns the handle of the axes) or use the ancestor function on one of the graphics objects in the axes to get the axes that contains it.

f = figure;
ax = axes; % output argument approach
h = plot(ax, 1:10, 1:10);

ax2 = ancestor(h, 'axes'); % ancestor approach
isequal(ax, ax2) % Both refer to the same axes

ans = logical
   1

f2 = ancestor(h, 'figure');
isequal(f, f2) % same figure too

ans = logical
   1

[Sim]

Thanks a lot!

In case I use subplot, and if I understood correctly, I then need to call subplot with an output argument, and add that output argument (i.e. the handle of the axes) everywhere I plot something, where I get/set "Children", and where I call findobj and legend, right?

In my secific case, I would need to use the output argument (i.e. the handle of the axes) in the following parts of code:

(1) ax = subplot(3,2,k); % <-- call subplot with an output argument (so it returns the handle of the axes) 
(2) p(1) = plot(ax,G,...
    p(2) = plot(ax,Gpath{i},...
    p(3) = plot(ax,Gpath{i},...
    p(4) = plot(ax,Gpath{i},...
    text(ax,...
    plot(ax,...
    rectangle(ax,...
(4) a = get(ax,'Children');
(5) b = findobj(ax,'Type','GraphPlot');
(6) set(ax,'Children',[c; setdiff(a,b)])
(7) legend(ax,c)

The entire code would then read and run as follows:

clear all; clc; close all;

% Graph
s = [1 1 1 3 3 6 7 8 9  10  4 12 13  5 15 16 17 18 19 19 20 20 17 24 25  4 27 28 29];
t = [2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30];
G = graph(s,t);
% Node ID:   1 2 3 4 5 6 7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
G.Nodes.X = [2 1 3 2 4 4 5  4  5  4  5  1  3  3  5  6  7  6  8  7  9  8  9  8  9 10  1  1  0  1]'; 
G.Nodes.Y = [2 1 3 9 3 5 8 12 13 18 21 15 18 21  0  2  8 12 15 20 10 22 18  5  4  4  5  8 12 23]';

% Subgraphs
Gpath{1} = subgraph(G,shortestpath(G,4,14));
Gpath{2} = subgraph(G,shortestpath(G,4,26));
Gpath{3} = subgraph(G,shortestpath(G,4,30));
Gpath{4} = subgraph(G,shortestpath(G,3,10));
Gpath{5} = subgraph(G,shortestpath(G,3,28));
Gpath{6} = subgraph(G,shortestpath(G,3,21));
Gpath{7} = subgraph(G,shortestpath(G,17,12));
Gpath{8} = subgraph(G,shortestpath(G,17,23));
Gpath{9} = subgraph(G,shortestpath(G,17,26));

% Figure
for k = 1 : 2
    ax = subplot(3,2,k);
    hold on
    p(1) = plot(ax,G,'XData',G.Nodes.X,'YData',G.Nodes.Y,'LineWidth',1,'EdgeColor','k','NodeColor','k');
    for i = [1 2 3]
        p(2) = plot(ax,Gpath{i},'XData',Gpath{i}.Nodes.X,'YData',Gpath{i}.Nodes.Y,'EdgeColor','y','NodeColor','y');
        p(2).NodeLabel = {};
        p(2).EdgeAlpha = 1;
        p(2).LineWidth = 5;
        % p(2).DisplayName = 'Banana';
    end
    for i = [7 8 9]
        p(3) = plot(ax,Gpath{i},'XData',Gpath{i}.Nodes.X,'YData',Gpath{i}.Nodes.Y,'EdgeColor','g','NodeColor','g');
        p(3).NodeLabel = {};
        p(3).EdgeAlpha = 1;
        p(3).LineWidth = 9;
        p(3).DisplayName = 'Apple';
    end
    for i = [4 5 6]
        p(4) = plot(ax,Gpath{i},'XData',Gpath{i}.Nodes.X,'YData',Gpath{i}.Nodes.Y,'EdgeColor','r','NodeColor','r');
        p(4).NodeLabel = {};
        p(4).EdgeAlpha = 1;
        p(4).LineWidth = 15;
        p(4).DisplayName = 'Strawberry';
    end
    text(ax,8,.2,'hello')
    plot(ax,[0.5 0.6],[0 6],'color',[0.6 0.6 0.6],'LineWidth',5);
    rectangle(ax,'Position',[7,1,2,0.5],'FaceColor',[0.4 0.4 0.4]);


    a = get(ax,'Children');
    b = findobj(ax,'Type','GraphPlot');
    idx1 = find(~cellfun(@isempty,{b.DisplayName})); % GraphPlots with name
    idx2 = find(cellfun(@isempty,{b.DisplayName}));  % GraphPlots without name
    c = vertcat(flipud(b(idx2)),flipud(b(idx1)));
    set(ax,'Children',[c; setdiff(a,b)])
    legend(ax,c)

end

Answer 2

[Sim]

Solved just by adding "gca", as first argument of findobj, i.e. by using:

b = findobj(gca,'Type','GraphPlot');