Underscore doesn't work for step legend
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I'm trying to plot two step responses alongside with experimental results. Plot looks okay, but for some reason Matlab inserts a backslash before underscore for the step legend. How do I fix the legend?
\omega_{experimental} and \theta_{experimental} work
\omega_{modelo} and \theta_{modelo} don't
f2 = figure('DefaultAxesFontSize', 14);
plot(t_exp,omega_exp,'red');
hold on
plot(t_exp,theta_exp,'blue');
hold on
step(12*Go);
hold on
step(12*Gt);
title('Comparação do modelo obtido com a resposta experimental')
xlabel('Tempo (segundos)')
ylabel(' ')
legend({'$\omega_{experimental} (rad/s)$','$\theta_{experimental} (rad)$',...
'$\omega_{modelo} (rad/s)$','$\theta_{modelo} (rad)$'},...
'Interpreter','latex','Location','southeast','FontSize',16);
set(gca,'XLim',[0 1])
This is what I'm getting:
This is the backslash that Matlab inserts for some reason (seen by double-clicking the plot legend):
Full code is attached. Thanks in advance!
2 个评论
Adam Danz
2019-5-3
Works fine for me (copied your call to legend)
figure
plot(rand(5,4))
legend({'$\omega_{experimental} (rad/s)$','$\theta_{experimental} (rad)$',...
'$\omega_{modelo} (rad/s)$','$\theta_{modelo} (rad)$'},...
'Interpreter','latex','Location','southeast','FontSize',16);
Vitor Sternlicht
2019-5-3
采纳的回答
The escape character (\) is mistakenly added in legend() > setDisplayNames() even though the latex interpreter is correctly assigned. This evokes updateGroupInfo() which adds the escape character. Even if you assign the string to the DisplayName property prior to calling legend(), it immediately addes the escape character. However, the string is correctly assign in latex (or tex) format if the assignment is done after the legend is created. This is because you are only altering the legend string and therefore bypassing the updateGroupInfo() function.
Links to other threads in this forum that have revealed this problem with other plotting functions:
Workaround 1
Call the legend twice.
% reproducible example
figure();
s = tf('s');
G = exp(-s) * (0.8*s^2+s+2)/(s^2+s);
T = feedback(ss(G),1);
step(T)
legend({'$\omega_{modelo} (rad/s)$'},...
'Interpreter','latex','Location','southeast','FontSize',16);
legend({'$\omega_{modelo} (rad/s)$'})
Workaround 2
Assign the DisplayName property after creating the legend.
figure
s = tf('s');
G = exp(-s) * (0.8*s^2+s+2)/(s^2+s);
T = feedback(ss(G),1);
step(T);
legend('Interpreter', 'latex')
axisObjs = get(gca, 'Children');
set(axisObjs(1), 'DisplayName', '$\omega_{modelo} (rad/s)$')
更多回答（1 个）
per isakson
2019-5-3
编辑：per isakson
2019-5-4
With R2018b. Deep inside and after too many if-statements to keep track of a backslash is added.
C:\Program Files\MATLAB\R2018b\toolbox\shared\controllib\graphics\@wavepack\@waveform\updateGroupInfo.m
line 19-21
if ~this.LegendSubsriptsEnabled
dispname = strrep(dispname,'_','\_');
end
C:\Program Files\MATLAB\R2018b\toolbox\matlab\scribe\legend.m
Why Line and Group, respectively?
The order of the text-arguments in the call of legend() matters
lh = legend({
'$\omega_{experimental} (rad/s)$' ...
, '$\theta_{experimental} (rad)$' ...
, '$\omega_{modelo} (rad/s)$' ...
, '$\theta_{modelo} (rad)$' } ...
, 'Interpreter','latex','Location','southeast','FontSize',16);
lh.String{3} = '$\omega_{modelo} (rad/s)$';
lh.String{4} = '$\theta_{modelo} (rad/s)$';
lh.String{4} = '$\theta_{modelo} (rad/s)$';
String(4) twice is not a copy&paste error!
2 个评论
Adam Danz
2019-5-3
+1
same in r2019a
Walter Roberson
2019-5-3
Good tracking! I had just traced it down to that same assignment in legend.m, but had not at all noticed the listener that triggers the behaviour you noticed!
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